Inactivating pathogens and producing highly immunogenic inactivated vaccines using a dual oxidation process
11633470 · 2023-04-25
Assignee
Inventors
Cpc classification
C12N7/00
CHEMISTRY; METALLURGY
C12N2770/24134
CHEMISTRY; METALLURGY
C12N2760/16134
CHEMISTRY; METALLURGY
A61K39/105
HUMAN NECESSITIES
C12N2760/16131
CHEMISTRY; METALLURGY
Y02A50/30
GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
C12N2770/36134
CHEMISTRY; METALLURGY
International classification
A61K39/00
HUMAN NECESSITIES
Abstract
Provided are surprisingly effective methods for inactivating pathogens, and for producing highly immunogenic vaccine compositions containing an inactivated pathogen rendered noninfectious by exposure to a Fenton reagent, or by exposure to a Fenton reagent or a component thereof in combination with a methisazone reagent selected from the group consisting of methisazone, methisazone analogs, functional group(s)/substructure(s) of methisazone, and combinations thereof. The methods efficiently inactivate pathogens, while substantially retaining pathogen antigenicity and/or immunogenicity, and are suitable for inactivating pathogens, or for the preparation of vaccines for a wide variety of pathogens with genomes comprising RNA or DNA, including viruses and bacteria. Also provided are highly immunogenic inactivated vaccine compositions prepared by using any of the disclosed methods, and methods for eliciting an immune response in a subject by administering such vaccine compositions.
Claims
1. A method for inactivating a pathogen, the method comprising contacting a pathogen having an RNA or DNA genome with hydrogen peroxide, or with a Fenton reagent containing hydrogen peroxide in combination with at least one transition metal selected from the group consisting of Cu and Fe, and in either case with a methisazone reagent, in an amount and for a time-period sufficient to render the pathogen noninfectious, wherein inactivation of the pathogen proceeds at an increased rate relative to that produced by contacting the pathogen with either the hydrogen peroxide or the Fenton reagent alone.
2. The method of claim 1, wherein a mixture of different transition metal ions are used in combination with hydrogen peroxide.
3. The method of claim 1, wherein the pathogen is a virus or a bacterium.
4. The method of claim 3, wherein the pathogen is a virus.
5. The method of claim 4, wherein the virus is from Family Togaviridae, Flaviviridae, Poxviridae, or Orthomyxoviridae.
6. The method of claim 4, wherein the virus is from Family: Togaviridae, Genus: Alphavirus, Family: Flaviviridae, Genus: Flavivirus, Family: Poxviridae, Genus Orthopoxvirus, or Family: Orthomyxoviridae, Genus: Influenzavirus.
7. The method of claim 6, wherein the virus is chikungunya virus (CHIKV, Family: Togaviridae, Genus: Alphavirus), dengue virus serotypes 1-4 and yellow fever virus (DENV 1-4, YFV, Family: Flaviviridae, Genus: Flavivirus), vaccinia virus (VV, Family: Poxviridae, Genus: Orthopoxvirus), or influenza virus (Family: Orthomyxoviridae, Genus: Influenzavirus).
8. The method of claim 3, wherein the pathogen is a bacterium.
9. The method of claim 8, wherein the bacterium is Campylobacter.
10. The method of claim 9, wherein the Campylobacter is C. coli or C. jejuni.
11. The method of claim 8, wherein the bacterium is Shigella spp.
12. The method of claim 8, wherein the bacterium is Listeria spp.
13. The method of claim 1, wherein the pathogen is isolated or purified prior to contacting with the Fenton reagent.
14. The method of claim 1, wherein the methisazone reagent comprises a compound having formula I: ##STR00015## wherein R.sub.1 is independently H or C1-C4 alkyl optionally substituted with —OH; wherein R.sub.2 is independently H, C1-C2 alkyl optionally substituted with —OH or with aryl; and wherein X is independently H or halogen; and pharmaceutically acceptable salts thereof.
15. The method of claim 14, wherein X and R.sub.2 are H; and wherein R.sub.1 is H (isatin β-thiosemicarbazone), —CH.sub.3 (N-methyl-isatin β-thiosemicarbazone (methisazone)), or propyl (N-propyl-isatin β-thiosemicarbazone).
16. The method of claim 15, wherein R.sub.1 is —CH.sub.3 (N-methyl-isatin β-thiosemicarbazone (methisazone)).
17. The method of claim 1, wherein the methisazone reagent comprises one or more compounds each having one of formulas II-V: ##STR00016## wherein R.sub.1 is H or C1-C4 alkyl optionally substituted with —OH; and wherein X is independently H or halogen; and salts, including pharmaceutically acceptable salts thereof; ##STR00017## wherein R.sub.1 is H or C1-C4 alkyl optionally substituted with —OH; wherein X is independently H or halogen; and wherein R.sub.2 is independently H, C1-C2 alkyl optionally substituted with —OH, or with aryl; and salts, including pharmaceutically acceptable salts thereof; and ##STR00018## wherein R.sub.2 and R.sub.3 are independently H, C1-C2 alkyl optionally substituted with —OH, or with aryl; and salts, including pharmaceutically acceptable salts thereof; and combinations thereof.
18. The method of claim 17, wherein X of formula (II) is H, and R.sub.1 of formula (II) is H (isatin), —CH.sub.3 (N-methyl-isatin), or propyl (N-propyl-isatin); wherein X, R.sub.1, and R.sub.2 of formula (III) are H (indole, 2,3-dione, 3-hydrazone); wherein R.sub.2 and R.sub.3 of formula (IV) are H (thiosemicarbazide); and wherein R.sub.2 and R.sub.3 of formula (V) are H (semicarbazide).
19. The method of claim 17, wherein the methisazone reagent comprises thiosemicarbazide and a compound having formula VI: ##STR00019## wherein R.sub.1 is H or C1-C4 alkyl.
20. The method of claim 19, wherein R.sub.1 is H (isatin), —CH.sub.3 (N-methyl-isatin), or propyl (N-propyl-isatin).
21. The method of claim 19, wherein R.sub.1 is H (isatin).
Description
BRIEF DESCRIPTION OF THE DRAWINGS
(1)
(2)
(3)
(4)
(5)
(6)
(7)
(8)
(9)
(10)
(11)
(12)
(13)
(14)
(15)
(16)
(17)
(18)
(19)
(20)
(21)
DETAILED DESCRIPTION OF TRE INVENTION
(22) While inactivated vaccines represent a critical component of the health care system for both human and veterinary fields of medicine, the prior art processes of inactivation damage key antigenic epitopes of target pathogens (e.g., viral and bacterial), leading to suboptimal responses in vaccines and reductions in vaccine efficacy.
(23) Particular aspects of the present invention circumvent this problem by providing a new dual-oxidation approach involving Fenton-type chemistry. Fenton-type oxidative reactions require the use of redox-active transition metals (e.g., Cu, Fe, Cs, etc.) in combination with hydrogen peroxide (H.sub.2O.sub.2) to form oxidative byproducts, leading to microbial inactivation.
(24) The disclosed advanced Fenton-type dual-oxidation process was successfully applied to pathogens having either RNA or DNA genomes, including three exemplary bacteria (both Gram-positive and Gram negative examples, all with DNA genomes) including Campylobacter (e.g., C. coli or C. jejuni), Shigella spp, and Listeria (e.g., Listeria monocytogenes), and eight viruses (7 RNA genome viruses and 1 DNA genome virus) in four unrelated virus families as vaccine targets (e.g., chikungunya virus (CHIKV, Family: Togaviridae, Genus: Alphavirus), dengue virus serotypes 1-4 (DENV1, DENV2, DENV3, DENV4) and yellow fever virus (YFV), Family: Flaviviridae, Genus: Flavivirus), vaccinia virus (VV), Family: Poxviridae, Genus: Orthopoxvirus) and influenza virus (Family: Orthomyxoviridae, Genus: Influenzavirus A)) in which simple oxidation (e.g., hydrogen peroxide (H.sub.2O.sub.2) alone) was found to be suboptimal. For CHIKV, DENV and YFV, in vitro antigenicity was assessed through virus-specific ELISA tests based on monoclonal antibodies directed at sensitive neutralizing epitopes. Antigenicity for influenza was assessed through hemagglutination activity (HA), a direct measurement of viral protein function. In vivo enhancement of vaccine antigens was assessed through functional humoral immune assays, such as neutralizing antibody titers (CHIKV, DENV and YFV) or hemagglutination inhibition (HAI, influenza) responses following vaccination.
(25) The disclosed dual oxidation-based inactivation conditions were successfully demonstrated to enhance maintenance of in vitro antigenicity when compared, for example, to H.sub.2O.sub.2 alone, and for CHIKV, DENV, YFV and influenza, the dual-oxidation based inactivation approach demonstrated high antigenicity as well as complete virus inactivation. When these vaccines were tested in vivo, they provided antiviral immune responses equivalent or superior to that achieved through standard H.sub.2O.sub.2-based inactivation conditions, and in some cases equivalent to that seen with live virus. The disclosed dual-oxidation performed using Fenton-type chemistry thus provides robust pathogen inactivation with maintained antigenic properties, and enhances immunologic responses following vaccination.
(26) Fenton-Type Reactions
(27) Fenton-type chemical reactions are generally described (e.g., by Barbusiński, K., Fenton Reaction—Controversy concerning the chemistry. Ecological Chemistry and Engineering, 2009. 16(3): p. 347-358 incorporated herein in its entirety for its teachings related to Fenton-type reactants and reactions) using the following chemical equation:
M.sup.n++H.sub.2O.sub.2.fwdarw.M.sup.(n+1)++HO.sup.−+HO. (eq. 1)
(28) In equation 1, M is a transition metal that can interact with H.sub.2O.sub.2. This reaction leads to the decomposition of H.sub.2O.sub.2, resulting in the production of a hydroxyl ion (HO.sup.−) and the highly reactive hydroxyl radical (HO.). Note that certain transition metals, such as Fe and Cu, are considered particularly redox active, and most efficient in promoting this reaction. In the complete reaction, the metal ion is returned to its original oxidation state through an additional reaction with H.sub.2O.sub.2, making the metal ion a true catalyst (Id). As an example, the overall reaction with Cu.sup.2+ can be written as follows:
Cu.sup.2++H.sub.2O.sub.2.fwdarw.Cu.sup.++HO.sub.2.Math.+H.sup.+ (eq. 2)
Cu.sup.++H.sub.2O.sub.2.fwdarw.Cu.sup.2++HO.sup.−+HO. (eq. 3)
(29) In equation 2, H.sub.2O.sub.2 acts as a reducing agent, reducing Cu.sup.2+ to Cu.sup.+. In equation 3, the Cu.sup.+ in turn reduces H.sub.2O.sub.2 leading to the production of the reactive hydroxyl radical and return to the Cu.sup.2+ oxidation state, allowing subsequent rounds of catalysis. As described, there may be additional side reactions that occur during Fenton-type reactions (Id).
(30) Prior Art Use of Fenton-Type Oxidation was Only as a Broad-Based Sterilization and Pathogen Decontamination System
(31) As mentioned above, similar to case for the standalone disinfectant uses of H.sub.2O.sub.2 prior to Applicants' U.S. Pat. Nos. 8,124,397 and 8,716,000, prior to the present disclosure, Fenton-type reactions were known in the art only for inactivation/sterilization of microbial pathogens (e.g., see Sagripanti, J. L., L. B. Routson, and C. D. Lytle, Virus inactivation by copper or iron ions alone and in the presence of peroxide. Appl Environ Microbiol, 1993. 59(12): p. 4374-6; Nieto-Juarez, J. I., et al., Inactivation of MS2 coliphage in Fenton and Fenton-like systems: role of transition metals, hydrogen peroxide and sunlight. Environ Sci Technol, 2010. 44(9): p. 3351-6).
(32) For example, Fenton-type oxidation has been recognized by multiple groups as a potent antimicrobial platform. FDA researchers first detailed the systematic study of Fenton-type reactions as an antimicrobial approach, specifically aimed towards use in the sterilization of medical devices (Sagripanti, J. L., Metal-based formulations with high microbicidal activity. Appl Environ Microbiol, 1992. 58(9): p. 3157-62). Using the Junin virus (ssRNA, Genus: Arenavirus) as a model pathogen, rapid inactivation was observed with both Fe.sup.3+ and Cu.sup.2+ as catalysts in the redox reaction (eq. 1), working as well as standard sterilization approaches (2% glutaraldehyde) following optimization. As noted by the author at the time, the use of either of these metals was particularly attractive for medical purposes, given that normal human serum contains relatively high amounts of both Fe and Cu. For instance, total serum Cu levels in normal subjects ranges from 700-1500 μg/L (11-24 μM) (McClatchey, K. D., Clinical laboratory medicine. 2nd ed. 2002, Philadelphia: Lippincott Wiliams & Wilkins. xiv, p. 452), while Fe levels range from 500-1700 μg/L (9-30 μM) (Lippincott Williams & Wilkins., Nursing. Deciphering diagnostic tests. Nursing. 2008, Philadelphia, Pa.: Wolters Kluwer/Lippincott Williams & Wilkins. vii, p. 13). This same research group continued to expand on the Cu-based Fenton reaction, demonstrating antimicrobial activity against multiple viral targets such as ϕX174 bacteriophage (ssDNA), 17 bacteriophage (dsDNA), herpes simplex virus (HSV, dsDNA) and ϕ6 bacteriophage (dsRNA) (Sagripanti, J. L., L. B. Routson, and C. D. Lytle, Virus inactivation by copper or iron ions alone and in the presence of peroxide. Appl Environ Microbiol, 1993. 59(12): p. 4374-6). Additional studies with HSV using the H.sub.2O.sub.2/Cu.sup.2+ system (0.01% H.sub.2O.sub.2, 16 μM Cu.sup.2+) confirmed rapid inactivation and suggested that direct oxidation of nucleic acid underpins the viral inactivation (Sagripanti, J. L., et al., Mechanism of copper-mediated inactivation of herpes simplex virus. Antimicrob Agents Chemother, 1997. 41(4): p. 812-7), with supporting studies demonstrating the high affinity of Cu.sup.2+ for nucleic acids (Sagripanti, J. L., P. L. Goering, and A. Lamanna, Interaction of copper with DNA and antagonism by other metals. Toxicol Appl Pharmacol, 1991. 110(3): p. 477-85) and the ability of H.sub.2O.sub.2/Cu.sup.2+ systems to induce strand breaks in nucleic acids (Toyokuni, S. and J. L. Sagripanti, Association between 8-hydroxy-2′-deoxyguanosine formation and DNA strand breaks mediated by copper and iron, in Free Radic Biol Med. 1996: United States. p. 859-64). Several other groups have also demonstrated the pathogen inactivation potential of H.sub.2O.sub.2/Cu.sup.2+ systems. Nieto-Juarez, et. al., demonstrated rapid inactivation of MS2 bacteriophage (ssRNA) using 50 μM H.sub.2O.sub.2 (0.00017%) and 1 μM Cu.sup.2+, with the authors suggesting its potential for wastewater decontamination (Nieto-Juarez, J. L., et al., Inactivation of MS2 coliphage in Fenton and Fenton-like systems: role of transition metals, hydrogen peroxide and sunlight. Environ Sci Technol, 2010. 44(9): p. 3351-6) (see also Nguyen, T. T., et al., Microbial inactivation by cupric ion in combination with H.sub.2O.sub.2: role of reactive oxidants. Environ Sci Technol, 2013. 47(23): p. 13661-7).
(33) In total, these prior art studies were strictly in the context of decontamination, and merely demonstrate that the H.sub.2O.sub.2/Cu.sup.2+ system was known to be able to efficiently kill/sterilize model pathogens.
(34) Simple Oxidation with H.sub.2O.sub.2 Limited Vaccine Immunogenicity with Certain Pathogen Targets
(35) Applicants have previously shown (e.g., U.S. Pat. Nos. 8,124,397 and 8,716,000) that sole use of H.sub.2O.sub.2 as a simple oxidation agent provides suitable inactivation agent for various vaccine candidates.
(36) However, during continued development of oxidizing with H.sub.2O.sub.2 alone, instances with certain pathogens in which antigenicity and immunogenicity were reduced during the inactivation process were encountered. For example, during recent early-stage development of a chikungunya virus (CHIKV) vaccine candidate, we found as presented herein under working Example 1, that treatment with 3% H.sub.2O.sub.2 under standard conditions destroyed neutralizing epitopes and led to a nearly complete loss of antigenicity, as judged through in vitro potency testing using envelope-specific MAbs (
(37) Dual Oxidation-Based Microbial Inactivation was Found by Applicants to Have a Fundamentally Different Mechanism Compared with Simple Oxidation with H.sub.2O.sub.2 Alone, Thereby Initially Discouraging the Potential Use of Dual Oxidation-Based Microbial Inactivation for the Development of Advanced Efficacious Vaccine Antigens.
(38) While Fenton-type reactions have only been used in the prior art for killing pathogens, and have not been used or suggested for use in the development of vaccines, Applicants nonetheless tested, as shown herein under working Example 2, such reactions for the potential to inactivate microbial pathogens for purpose of vaccine production. The initial inactivation data was surprising and unexpected, because in contrast to H.sub.2O.sub.2, it was found that the total protein concentration of the solution during the inactivation procedure impacts H.sub.2O.sub.2/CuCl.sub.2 dual-oxidation inactivation kinetics. Protein concentration had been previously shown to have no impact on viral inactivation using Applicants' standard H.sub.2O.sub.2 approach. As shown in
(39) The unexpected dependence on total protein concentration of the solution during the dual inactivation indicated that a fundamentally different mechanism was involved compared to H.sub.2O.sub.2 alone as in Applicants' prior simple oxidation based methods (e.g., with H.sub.2O.sub.2 alone) (e.g., U.S. Pat. Nos. 8,124,397 and 8,716,000), and thus the efficacy/use of a dual oxidation-based inactivation procedure for effective vaccine production was entirely questionable and unpredictable.
(40) Applicants, despite the discovery of a different, protein concentration-dependent mechanism, nonetheless performed additional experiments discussed herein and included in the working examples below, to show that Fenton-type dual oxidation reactions can surprisingly be used to effectively inactivate microbial pathogens, and provide for highly immunogenic and effective vaccines.
(41) Dual Oxidation-Based Inactivation in the Development of Advanced Vaccine Antigens.
(42) The Fenton-type oxidation (e.g., the H.sub.2O.sub.2Cu.sup.2+ system) has not been used or suggested for use in the art for the development of vaccines. Despite Applicants' discovery that a fundamentally different mechanism was involved (i.e., protein concentration dependence), Applicants nonetheless explored this system's utility in the development of a vaccine candidate against CHIKV, as this target had demonstrated poor immunogenicity with no induction of neutralizing antibodies using a standard H.sub.2O.sub.2 inactivation approach (
(43) Each component of the system alone (H.sub.2O.sub.2 or CuCl.sub.2, a source of Cu.sup.2+ ions) was first assessed in terms of their respective ability to fully inactivate virus while maintaining appropriate antigenicity. Antigenicity is defined by the ability to measure intact protein epitopes on the virus surface using monoclonal antibodies that bind specific virus neutralizing epitopes. Alternatively, structural antigenicity can also be defined by physiologic protein function/binding assays, such as those used to measure hemagglutination activity of influenza virus. The antigenicity results based on monoclonal antibody binding to CHIKV are shown herein under working Example 3.
(44) Increasing concentrations of either decontamination reagent (
(45) Surprisingly, by contrast, using the combined H.sub.2O.sub.2/CuCl.sub.2 system, an optimal inactivation condition was identified that fully maintained antigenicity while leading to complete viral inactivation (
(46) CuCl.sub.2/H.sub.2O.sub.2—CHIKV Vaccination Generated Rapid and Robust Neutralizing Antibody Titers, and Demonstrated Full Protection Against Arthritic Disease
(47) To assess the immunogenicity of the H.sub.2O.sub.2/CuCl.sub.2-treated CHIKV candidate, vaccine antigen was formulated with alum adjuvant and used to immunize mice at several dose levels (10 or 40 μg per animal). As shown herein under working Example 4, CuCl.sub.2/H.sub.2O.sub.2—CHIKV vaccination generated rapid and robust neutralizing antibody titers (
(48) H.sub.2O.sub.2/CuCl.sub.2-Based Oxidation was Successfully Used in the Development of an Inactivated YFV Vaccine
(49) Based on the encouraging results demonstrated with CHIKV, a model alphavirus, the utility of the system for flaviviruses such as YFV was explored.
(50) As shown herein under working Example 5, preliminary analysis suggested that a concentration of 0.002% H.sub.2O.sub.2 and 1 μM CuCl.sub.2 represented a functional balance between antigenicity and rapid virus inactivation (
(51) H.sub.2O.sub.2/CuCl.sub.2-Based Oxidation was Successfully Used in the Development of an Inactivated DENV Vaccine
(52) Based on the encouraging results demonstrated with YFV, another model flavivirus, dengue 3 (DENV3) was tested in the H.sub.2O.sub.2/CuCl.sub.2 system.
(53) As shown herein under working Example 6, as with YFV, initial tests indicated that a concentration of 0.002% H.sub.2O.sub.2 and 1 μM CuCl.sub.2 represented an optimal approach for maintaining high antigenicity while also providing complete virus inactivation (
(54) In these experiments, the dual oxidation approach of H.sub.2O.sub.2/CuCl.sub.2 inactivation was more immunogenic than 3% H.sub.2O.sub.2 for all 4 dengue virus serotypes and resulted in an 8-fold to >800-fold increase in neutralizing antibody titers.
(55) CuCl.sub.2/H.sub.2O.sub.2-Based Oxidation Demonstrated Improved Antigenicity with Influenza Virus
(56) Given the positive results observed across two virus families (Togaviridae and Flaviviridae), an additional virus family was chosen to test using this new inactivation platform.
(57) As shown herein under working Example 7, inactivation of Influenza A virus (family Orthomyxoviridae) was tested using a standard 3% H.sub.2O.sub.2 approach, ultraviolet inactivation, or the optimized CuCl.sub.2/H.sub.2O.sub.2 system (0.002% H.sub.2O.sub.2 and 1 μM CuCl.sub.2). To assess antigenicity, a hemagglutination activity (HA) titration assay was used. Influenza viruses naturally agglutinate red blood cells, and maintenance of this activity throughout inactivation is considered key to the immunogenicity of the final vaccine product. As shown in
(58) Multiple Transition Metals Can Be Used in the Dual-Oxidation Approach to Vaccine Antigen Development
(59) Cu.sup.2+ (in the form of CuCl.sub.2) was the initial metal tested in the dual-oxidation vaccine antigen development studies described for CHIKV, DENV, YFV and influenza virus. However, as described above, other metals also have the potential to function in a similar manner.
(60) As shown herein under working Example 8, using DENV3 as a model virus, inactivation studies consisting of CuCl.sub.2 (Cu.sup.2+), FeCl.sub.3 (Fe.sup.3+) or CsCl (Cs.sup.+) and dilutions of H.sub.2O.sub.2 were tested for their potential in the development of vaccine antigen.
(61) As shown in
(62) Combinations of Transition Metals Demonstrate Synergy in the Dual-Oxidation Vaccine System
(63) As shown above in
(64) As shown herein under working example 9, to investigate potential synergistic effects, DENV3 model virus was inactivated with combinations of CuCl.sub.2 (Cu.sup.2+) and FeCl.sub.3 (Fe.sup.3+) at a set amount of H.sub.2O.sub.2 (0.01%). A number of CuCl.sub.2/FeCl.sub.3 conditions provided full inactivation while maintaining good antigenicity, demonstrating that using multiple metals in the same inactivation condition is feasible (
(65) Dual Oxidation Was Used to Provide Optimized Inactivation of Campylobacter for Improved Maintenance of Bacterial Morphology
(66) As shown herein under working Example 10, Campylobacter are small corkscrew-shaped bacteria that are typically ˜0.2 μm in diameter and ˜2-8 μm in length (
(67) Following inactivation with a standard 3% H.sub.2O.sub.2, solution for 5 hours at room temperature, the bacteria were substantially damaged with clear changes in morphology, including loss of gross cellular structure and substantial clumping (
(68) However, upon optimization of a dual-oxidation approach using 0.01% H.sub.2O.sub.2 and 2 μM CuCl.sub.2. Applicants surprisingly found that dual oxidation could completely inactivate Campylobacter coli (C. coli) while maintaining excellent bacterial morphology throughout the treatment period with microbes that remained indistinguishable from the untreated controls (
(69) In addition to retained structure, a critical parameter for preparing an inactivated whole-cell vaccine is to ensure complete microbe inactivation. Using the optimal conditions described above, inactivation kinetic studies were performed. As shown in
(70) CuCl.sub.2/H.sub.2O.sub.2-C. coli Vaccination Provided Protective Immunity in Rhesus Macaques
(71) As shown herein under working Example 11, Applicants determined vaccine efficacy in 60 CuCl.sub.2/H.sub.2O.sub.2-C. coli-immunized rhesus macaques from two outdoor sheltered housing groups, and then monitored the animals for Campylobacter culture-confirmed enteric disease.
(72) For this study, animals were vaccinated intramuscularly with the CuCl.sub.2/H.sub.2O.sub.2-C. coli vaccine candidate (inactivated using 0.01% H.sub.2O.sub.2 and 2 μM CuCl.sub.2), with a booster dose administered 6-months later. Vaccinated groups were selected based on prior disease history, with preference given to groups that had historically high incidence rates of Campylobacter infection. This approach provided increased robustness in evaluating protective efficacy. All adults/juveniles (n=59) received a 40-μg alum-adjuvanted dose, with 2 small infants (<2 Kg body weight) receiving a half-dose (20-μg). According to protocol, any animal diagnosed with Campylobacter-associated diarrhea during the first 14 days after vaccination would be excluded since vaccine-mediated protection would be unlikely to occur during this early period. One adult animal was excluded from the study due to Campylobacter-associated diarrhea on the day after vaccination. Serum samples were collected from all remaining vaccinated animals (n=59) at day 0 and at 6 months after primary vaccination at which time the animals received a booster dose of vaccine.
(73) Following primary vaccination, the Applicants observed a significant increase in Campylobacter-specific serum antibody titers (
(74) Interim analysis at 6 months after primary vaccination demonstrated no cases of C. coli or C. jejuni-associated diarrhea in the vaccinated group versus 76 cases of Campylobacter-diarrhea among the unvaccinated animals, representing a statistically significant protective effect against Campylobacter culture-positive diarrheal disease (P=0.035) after a single vaccination.
(75) Since nearly all human vaccines require at least two doses for optimal protective efficacy and the durability of immunological memory is often improved following booster vaccination, the Applicants followed the conservative approach of administering a booster vaccination at the 6 month time point and then continued to monitor the incidence of diarrheal disease among the NHP. At 250 days after primary vaccination, more cases of Campylobacter-associated enteric disease had continued to accrue among the unvaccinated population (reaching 8.7% or a total of 92 animals) whereas none of the animals (0/59) in the vaccinated cohort showed signs of disease and the statistical significance between the two groups increased to P=0.020.
(76) Methisazone Reagents
(77) As disclosed and discussed in detail above, oxidizing transition metals (e.g., Cu.sup.2+, Fe.sup.3+, etc.) can be used in conjunction with our peroxide-based vaccine development platform to enhance virus inactivation while limiting antigenic damage. However, for some pathogens it was noted that antigenic degradation can occur even when using this advanced dual-oxidation approach. To further improve vaccine development, additional compounds were searched/screened for the ability to interact synergistically with our disclosed dual-oxidation-based inactivation approach to increase the rate of inactivation while further reducing damage to immunogenic protein antigens. Through this search, methisazone (N-methylisatin β-thiosemicarbazone, CAS 1910-68-5; C.sub.10H.sub.10N.sub.4OS; MWt 234.3 Da; Synonyms: metisazone; Marboran; Marborane; 33T57; M-IBT; 1-methylisatin 3-thiosemicarbazide; N-methylisatin β-thiosemicarbazone) was identified by Applicants. Methisazone is one of a series of antiviral drugs developed by the Wellcome Foundation in the 1950s (Thompson R L., et al., J Immunol. 1953; 70:229-34; Bauer D J., Br J Exp Pathol. 1955; 36:105-14). Based on small animal efficacy studies with orthopoxviruses, methisazone was developed into the commercial product, Marboran®, and tested in several clinical trials including both the treatment of vaccinia complications, as well as prophylaxis and treatment for smallpox (Bauer D J., Ann N Y Acad Sci. 1965; 130:110-7).
(78) According to Bauer (Id), early case reports for the use of methisazone in the treatment of vaccinia complications (eczema vaccinatum and vaccinia gangrenosa) indicate it may have been effective, but the lack of controls and concomitant use of antivaccinial gamma globulin (in some cases) makes it challenging to confirm efficacy. Nevertheless, the lack of serious adverse events is encouraging. Mean initial doses were 152 mg/kg, with a total average dose of 809 mg/kg given over 3.75 days. For an estimated human subject weight of 70 kg, this would translate into ˜10 gr per dose, and ˜60 gr per treatment course. Bauer mentions that methisazone was used prophylactically prior to vaccinia vaccination, and was reported to reduce complications (Id).
(79) Thus, historical in vivo data demonstrates that methisazone is safe and even trace amounts of this compound will not be an issue in new vaccine and drug products.
(80) Some of the most impressive data for methisazone relates to smallpox prophylaxis as reported during an outbreak in Madras, India (Bauer D J et al., Lancet, 1963; 2:494-6). Of the close contacts receiving methisazone, only 3/1101 (0.27%) developed mild smallpox (no deaths), while 78/1126 (6.9%) developed smallpox, with 12 deaths. When focusing on only non-vaccinated subjects, 2/102 methisazone-treated subjects contracted smallpox (2%) while 28/100 (28%) of untreated controls contracted smallpox, with 11 deaths. Dosages were altered somewhat throughout the trial and consisted of either (1) 1.5 gr by mouth twice daily after meals for 4 days (12 gr total); (2) 3 gr by mouth twice daily after meals for 4 days (24 gr total); (3) two doses of 3 gr by mouth within a 12 hr period (6 gr total). Methisazone, in combination with CuSO.sub.4, has been described for the decontamination of viruses (Fox M P, et al., Ann N Y Acad Sci. 1977; 284:533-43; Logan J C, et al., J Gen Virol. 1975; 28:271-83), but not for vaccine production, and has never been used in conjunction with H.sub.2O.sub.2.
(81) Fenton-Type Chemistry Plus Methisazone Reagents
(82) Surprisingly, Applicants discovered that methisazone reagents, as described herein, interact synergistically with the presently disclosed dual-oxidation-based inactivation approach to substantially increase the rate of inactivation while further reducing damage to immunogenic protein antigens.
(83) In additional aspects, therefore, the disclosed dual-oxidation methods involving Fenton-type chemistry further comprise, as described in more detail below in the working Examples, the use of methisazone, methisazone analogs, or methisazone functional group(s)/substructure(s), providing even more efficient microbial inactivation relative to dual-oxidation alone, and with even more effective retention of immunogenicity relative to dual-oxidation alone.
(84) The exact mode of action for methisazone in the disclosed methods is unclear, though studies have shown that methisazone can complex with copper, and this complex has the capacity to bind both nucleic acid (Mikelens P E, et al., Biochem Pharmacol. 1976; 25:821-7) and protein (Rohde W, et al., J Inorg Biochem. 1979; 10:183-94). To explain Applicants' results, without being bound by mechanism, Applicants hypothesized that the methisazone-copper complex might preferentially bind nucleic acid of the whole pathogen, and once bound, H.sub.2O.sub.2 may then interact with the Cu.sup.2+ of the methisazone-copper complex in a classic Fenton-type reaction to release highly active hydroxyl radicals in the proximity of the bound nucleic acid (e.g., a nucleic acid-focused oxidation). This release of oxidative radicals may then lead to substantial, but localized, damage of the nucleic acid and inactivation of the pathogen. Applicants speculated, therefore, that lower amounts of H.sub.2O.sub.2 than would typically be needed to inactivate pathogens could be used, thus limiting off-site/collateral damage to protein epitopes. Additionally, or alternatively, isatin β-thiosemicarbazone compounds have also been shown to directly bind nucleic acid (Pakravan & Masoudian, Iran J Pharm Res. 2015; 14:111-23), suggesting that this class of compounds alone may be able to open up nucleic acid macromolecules (e.g., by intercalation, and/or minor groove binding). Applicant speculated that if this was true, it may allow for greater access of oxidizing agents to the nucleic acid target to enhance oxidation-based virus inactivation.
(85) Methisazone Enhanced the Rate of Both Single and Dual Oxidation-Based Virus Inactivation
(86) As shown herein under working Example 12, Applicants determined that methisazone enhanced the rate of both single and dual oxidation-based virus inactivation. As shown in
(87) Further, while methisazone alone had a minimal impact on virus inactivation (
(88) Methisazone Enhanced the Rate of Dual Oxidation-Based Bacterial Inactivation
(89) As shown herein under working Example 13, Applicants determined that methisazone enhanced the rate of dual oxidation-based bacterial inactivation.
(90) The results of working Example 12 were extended to DNA-encoded bacteria (
(91) Methisazone Enhanced Inactivation Rates While Maintaining Antigenicity During Dual Oxidation-Based Virus Inactivation
(92) As shown herein under working Example 14, Applicants determined that methisazone enhanced inactivation rates while maintaining antigenicity during dual oxidation-based virus inactivation. To assess the impact of methisazone on antigenicity during inactivation, the exemplary model viruses CHIKV and DENV4 were treated with multiple inactivation approaches: high concentration H.sub.2O.sub.2 (single oxidation system), dual-oxidation (as described herein), or dual-oxidation with methisazone. As shown by the ELISA data in
(93) Chemical Analogs of Methisazone, or Methisazone Functional Groups/Substructures or Combinations Thereof, Enhanced Inactivation and Maintenance of Antigenicity During Dual Oxidation-Based Viral Inactivation
(94) As shown herein under working Example 15, Applicants determined that chemical analogs of methisazone, or methisazone functional groups/substructures or combinations thereof, enhanced inactivation and maintenance of antigenicity during dual oxidation-based viral inactivation.
(95) We tested several related compounds to determine if they provided similar enhancements to pathogen inactivation for vaccine development (
(96) Increasing Levels of Methisazone Relative to the Transition Metal Component of the Dual Oxidation System Improved the Antigenicity and Inactivation Profile of the Dual Oxidation System
(97) As shown herein under working Example 16, Applicants determined that increasing levels of methisazone relative to the transition metal component of the dual oxidation system improved the antigenicity and inactivation profile of the dual oxidation system.
(98) The impact of relative concentrations of methisazone and the transition metal in the dual-oxidation system (
(99) The Dual Oxidation-Based Inactivation Methods, and Including Those Further Comprising Use of a Methisazone Reagent, Have Broad Utility in the Development of Advanced Vaccines Against Pathogens Having Either RNA or DNA Genomes, Including but Not Limited to Viral and Bacterial Pathogens
(100) As discussed above, and shown in the working examples herein, the dual oxidation-based inactivation methods, and including those further comprising use of a methisazone reagent, were shown to have utility across not only eight viruses in four different viral Families, but also for three exemplary bacterial species (e.g., Campylobacter, a Gram-negative bacteria, at least a dozen species of which have been implicated in human disease, with C. jejuni and C. coli being the most common), Listeria monocytogenes (an exemplary gram-positive bacteria) and Shigella dysenteriae (an exemplary gram-negative bacteria).
(101) According to further aspects, the dual oxidation-based inactivation methods, and including those further comprising use of a methisazone reagent, have utility for producing highly immunogenic vaccines using, but not limited to the following exemplary microbes:
(102) Viruses. Non-limiting examples of viruses that can be inactivated using dual oxidation include the following families: Adenoviridae, Alloherpesviridae, Alphaflexiviridae, Alphaherpesvirinae, Alphatetraviridae, Alvernaviridae, Amalgaviridae, Ampullaviridae, Anelloviridae, Arenaviridae, Arteriviridae, Ascoviridae, Asfarviridae, Astroviridae, Autographivirinae, Avsunviroidae, Baculoviridae, Barnaviridae, Benyviridae, Betaflexiviridae, Betaherpesvirinae, Bicaudaviridae, Bidnaviridae, Birnaviridae, Bornaviridae, Bromoviridae, Bunyaviridae, Caliciviridae, Carmotetraviridae, Caulimoviridae, Chordopoxvirinae, Chrysoviridae, Circoviridae, Clavaviridae, Closteroviridae, Comovirinae, Coronaviridae, Coronavirinae, Corticoviridae, Cystoviridae, Densovirinae, Dicistroviridae, Endornaviridae, Entomopoxvirinae, Eucampyvirinae, Filoviridae, Flaviviridae, Fuselloviridae, Gammaflexiviridae, Gammaherpesvirinae, Geminiviridae, Globuloviridae, Gokushovirinae, Guttaviridae, Hepadnaviridae, Hepeviridae, Herpesviridae, Hypoviridae, Hytrosaviridae, Iflaviridae, Inoviridae, Iridoviridae, Leviviridae, Lipothrixviridae, Luteoviridae, Malacoherpesviridae, Marnaviridae, Marseilleviridae, Megabirnaviridae, Mesoniviridae, Metaviridae, Microviridae, Mimiviridae, Myoviridae, Nanoviridae, Narnaviridae, Nimaviridae, Nodaviridae, Nudiviridae, Nyamiviridae, Ophioviridae, Orthomyxoviridae, Orthoretrovirinae, Papillomaviridae, Paramyxoviridae, Paramyxovirinae, Partitiviridae, Parvoviridae, Parvovirinae, Peduovirinae, Permutotetraviridae, Phycodnaviridae, Picobirnaviridae, Picornaviridae, Picovirinae, Plasmaviridae, Pneumovirinae, Podoviridae, Polydnaviridae, Polyomaviridae, Pospiviroidae, Potyviridae, Poxviridae, Pseudoviridae, Quadriviridae, Reoviridae, Retroviridae, Rhabdoviridae, Roniviridae, Rudiviridae, Secoviridae, Sedoreovirinae, Siphoviridae, Sphaerolipoviridae, Spinareovirinae, Spiraviridae, Spounavirinae, Spumaretrovirinae, Tectiviridae, Tevenvirinae, Togaviridae, Tombusviridae, Torovirinae, Totiviridae, Turriviridae, Tymoviridae, and Virgaviridae.
(103) Exemplary viral species include poliovirus, measles virus, mumps virus, parainfluenza virus, Newcastle disease virus, rubella virus, Eastern, Western and Venezuelan Equine Encephalitis Viruses, Lassa virus, lymphocytic choriomeningitis virus, West Nile virus, Dengue virus, Yellow fever virus, Tick-borne encephalitis virus, St. Louis encephalitis virus, Japanese Encephalitis virus, Zika virus, varicella zoster virus, cytomegalovirus, herpes simplex viruses, retroviruses including HIV (human immunodeficiency virus), hepatitis A virus, hepatitis B virus, hepatitis C virus, influenza viruses, rabies virus, molluscum contagiosum, smallpox virus, vaccinia virus, Sindbis virus, swine influenza virus, porcine parvovirus, porcine circovirus, chikungunya virus, porcine reproductive and respiratory syndrome virus, canine distemper virus, canine parvovirus, canine adenovirus Type-2, canine parainfluenzavirus, and canine coronavirus.
(104) Bacteria. Bacterial pathogens can also be inactivated using dual oxidation, and including dual oxidation further comprising use of a methisazone reagent, for use in producing highly immunogenic vaccine compositions. Non-limiting examples of bacteria that can be inactivated using dual oxidation include the following families: Acanthopleuribacteraceae, Acetobacteraceae, Acholeplasmataceae, Acholeplasmataceae, Acidaminococcaceae, Acidilobaceae, Acidimicrobiaceae, Acidimicrobiaceae, Acidithiobacillaceae, Acidobacteriaceae, Acidothermaceae, Actinomycetaceae, Actinopolysporaceae, Actinospicaceae, Actinosynnemataceae, Aerococcaceae, Aeromonadaceae, Akkermansiaceae, Alcaligenaceae, Alcaligenaceae, Alcanivoracaceae, Algiphilaceae, Alicyclobacillaceae, Alteromonadacae, Anaerolineaceae, Anaeroplasmataceae, Anaeroplasmataceae, Anaplasmataceae, Aquificaceae, Aquificaceae, Archaeoglobaceae, Armatimonadaceae, Aurantinmonadaceae, Bacillaceae, Bacteriovoracaceae, Bacteroidaceae, Bacteroidaceae, Bartonellaceae, Bartonellaceae, Bdellovibrionaceae, Beijerinckiaceae, Beijerinckiaceae, Beutenbergiaceae, Bifidobacteriaceae, Blattabacteriaceae, Bogoriellaceae, Brachyspiraceae, Bradyrhizobiaceae, Bradyrhizobiaceae, Brevibacteriaceae, Brevinemataceae, Brucellaceae, Brucellaceae, Burkholderiaceae, Burkholderiaceae, Caldicoprobacteraceae, Caldilineaceae, Caldisericaceae, Caldisphaeraceae, Campylobacteraceae, Cardiobacteriaceae, Carnobacteriaceae, Caryophanaceae, Catalimonadaceae, Catenulisporaceae, Caulobacteraceae, Caulabacteracecae, Celerinatantimonadaceae, Cellulomonadaceae, Chitinophagaceae, Chlamydiaceae, Chlamydiaceae, Chlorobiaceae, Chlorobiaceae, Chloroflexaceae, Christensenellaceae, Chromatiaceae, Chrysiogenaceae, Chrysiogenaceae, Chthonomonadaceae, Clostridiaceae, Cohaesibacteraceae, Colwelliaceae, Comamonadaceae, Comamonadaceae, Conexibacteraceae, Coriobacteriaceae, Coriobacteriaceae, Cornyebacteriaceae, Coxiellaceae, Crenotrichaceae, Cryomorphaceae, Cryptosporangiaceae, Cyclobacteriaceae, Cystobacteraceae, Cytophagaceae, Deferribacteraceae, Deferribacteraceae, Defluviitaleaceae, Dehalococcoidaceae, Deinococcaceae, Demequinaceae, Dermabacteraceae, Dermacoccaceae, Dermatophilaceae, Desulfarculaceae, Desulfobacteraceae, Desulfobulbaceae, Desulfohalobiaceae, Desulfomicrobiaceae, Desulfonatronaceae, Desulfovibrionaceae, Desulfurellaceae, Desulfurobacteriaceae, Desulfurococcaceae, Desilfuromonadaceae, Dictyoglomaceae, Dictyoglomaceae, Dietziaceae, Ectothiorhodospiraceae, Ehrlichiaceae, Elusimicrobiaceae, Enterobacteriaceae, Enterococcaceae, Entomoplasmataceae, Entomoplasmataceae, Erysipelotrichaceae, Erysipelotrichaceae, Erythrobacteraceae, Eubacteriaceae, Euzebyaceae, Ferrimonadaceae, Ferroplasmaceae, Fervidicoccaceae, Fibrobacteraceae, Fimbriimonadaceae, Flammeovirgaceae, Flavobacteriaceae, Flexibacteraceae, Francisellaceae, Frankiaceae, Fusobacteriaceae, Fusobacteriaceae, Gaiellaceae, Gallionellaceae, Gemmatimonadaceae, Geobacteraceae, Geodermatophilaceae, Glycomycetaceae, Gordoniaceae, Gracilibacteraceae, Granulosicoccaceae, Hahellaceae, Halanaerobiaceae, Halobacteriaceae, Halobacteroidaceae, Halomonadaceae, Haloplasmataceae, Halothiobacillaceae, Helicobacteraceae, Heliobacteriaceae, Herpetosiphonaceae, Holophagaceae, Holosporaceae, Holasporaceae, Hydrogenophilaceae, Hydrogenophilales, Hydrogenothermaceae, Hydrogenothermaceae, Hyphomicrobiaceae, Hyphomicrobiaceae, Hyphomonadaceae, Iamiaceae, Idiomarinaceae, Ignavibacteriaceae, Intrasporangiaceae, Jiangellaceae, Jonesiaceae, Kiloniellaceae, Kineosporiaceae, Kofleriaceae, Kordiimonadaceae, Ktedonobacteraceae, Lachnospiraceae, Lactobacillaceae, Legionellaceae, Lentisphaeraceae, Leptospiraceae, Leptospiraceae, Leptotrichiaceae, Lenconostocaceae, Listeriaceae, Litoricolaceae, Magnetococcaceae, Marinilabiliaceae, Methanobacteriaceae, Methanocaldococcaceae, Methanocellaceae, Methanococcaceae, Methanocorpusculaceae, Methanomicrobiaceae, Methanopyraceae, Methanoregulaceae, Methanosaetaceae (illegitimate), Methanosarcinaceae, Methanospirillaceae, Methanothermaceae, Methermicoccaceae, Methylobacteriaceae, Methylobacteriaceae, Methylococcaceae, Methylocystaceae, Methylocystaceae, Methylophilaceae, Methylophilaceae, Microbacteriaceae, Micrococcaceae, Micromonosporaceae, Microsphaeraceae, Mooreiaceae, Moraxellaceae, Moritellaceae, Mycobacteriaceae, Mycoplasmataceae, Mycoplasmataceae, Myroidaceae, Myxococcaceae, Nakamurellaceae, Nannocystaceae, Natranaerobiaceae, Nautiliaceae, Neisseriaceae, Nevskiaceae, Nitriliruptoraceae, Nitrosomonadaceae, Nitrospinaceae, Nocardiaceae, Nocardioidaceae, Nocardioidaceae, Nocardiopsaceae, Oceanaspirillaceae, Oleiphilaceae, Oligosphaeraceae, Opitutaceae, Orbaceae, Oscillachloridaceae, Oscillospiraceae, Oxalobacteraceae, Ovalobacteraceae, Paenibacillaceae, Parachlamydiaceae, Parachlamydiaceae, Parvularculaceae, Pasteurellaceae, Pasteuriaceae, Patulibacteraceae, Peptococcaceae, Peptostreptococcaceae, Peredibacteraceae, Phaselicystidaceae, Phycisphaeraceae, Phyllobacteriaceae, Phyllobacteriaceae, Picrophilaceae, Piscirickettsiaceae, Planctomycetacea, Planctomycetaceae, Planococcaceae, Polyangiaceae, Porphyromonadaceae, Porphyromonadaceae, Prevotellaceae, Prevotellaceae, Promicromonasporaceae, Propionibacteriaceae, Pseudoalteramonadaceae, Pseudomonadaceae, Pseudonocardiaceae, Psychromonadaceae, Puniceicoccaceae, Pyrodictiaceae, Rarobacteraceae, Rhabdochlamydiaceae, Rhizobiaceae, Rhizobiaceae, Rhodobacteraceae, Rhodobacteraceae, Rhodobiaceae, Rhodobiaceae, Rhodocyclaceae, Rhodospirillaceae, Rhodospirillaceae, Rhodothermaceae, Rickettsiaceae, Rickettsiaceae, Rikenellaceae, Rikenellaceae, Roseiflexaceae, Ruaniaceae, Rubritaleaceae, Rubrobacteraceae, Rubrobacteraceae, Ruminococcaceae, Sandaracinaceae, Sanguibacteraceae, Saprospiraceae, Schleiferiaceae, Segniliparaceae, Serpulinaceae, Shewanellaceae, Simkaniaceae, Simkaniaceae, Sinobacteraceae, Sneathiellaceae, Solimonadaceae, Solirubrobacteraceae, Sphaerobacteraceae, Sphaerobacteraceae, Sphingabacteriaceae, Sphingamonadaceae, Sphingomonadaceae, Spirillaceae, Spirochaetaceae, Spirochetaceae, Spiroplasmataceae, Spiroplasmataceae, Sporichthyaceae, Sporolactobacillaceae, Staphylococcaceae, Streptococcaceae, Streptomycetaceae, Streptosporangiaceae, Succinivibrionaceae, Sulfolobaceae, Sutterellaceae, Synergistaceae, Syntrophaceae, Syntrophobacteraceae, Syntrophomonadaceae, Syntrophorhabdaceae, Thermaceae, Thermithiobacillaceae, Thermoactinomycetaceae, Thermoanaerobacteraceae, Thermoanaerobacteriaceae, Thermacoccaceae, Thermadesulfobacteriaceae, Thermodesulfobacteriaceae, Thermodesulfobiaceae, Thermofilaceae, Thermogemmatisporaceae, Thermoleophilaceae, Thermolithobacteraceae, Thermomicrobiaceae, Thermomonosporaceae, Thermoplasmataceae, Thermoproteaceae, Thermosporotrichaceae, Thermotogacecie, Thioalkalispiraceae, Thiotrichaceae, Trueperaceae, Tsukamurellaceae, Turicibacteraceae, Veillonellaceae, Verrucomicrobiaceae, Verrucomicrobiaceae, Vibrionaceae, Victivallaceae, Waddliaceae, Waddliaceae, Williamsiaceae, Xanthobacteraceae, Xanthomonadaceae, Yaniellaceae, Aurantimonadaceae, Cenarchaeaceae, Haliangiaceae, Hydrogenimonaceae, Kordiimonadaceae, Mariprofundaceae, Nitrospiraceae, Parvularculacae, Procabacteriaceae, Saccharospirillaceae, and Salinisphaeraceae.
(105) Exemplary bacterial species include Campylobacter species (spp.), Shigella spp., Mycobacterium spp., Neisseria spp., Brucella spp., Borrelia spp., Chlamydia spp., Listeria monocytogenes, Bordatella pertussis, Clostridium spp., Enterococcus spp., Escherichia spp., Francisella tularensis, Haemophilus influenzae, Helicobacter pylori, Legionella pneumophila, Leptospira interrogans, Streptococcus pneumoniae, Pseudomonas aeruginosa, Rickettsia rickettsii, Salmonella spp., Staphylococcus aureus, and Bacillum anthracis. Gram-positive and Gram-negative bacteria, for example, are generally encompassed.
(106) Fungi. Highly immunogenic vaccine compositions can also be produced from fungal pathogens inactivated using dual oxidation. Exemplary fungal pathogens include: Aspergillus spp., Candida spp, Blastomyces spp., Coccidioides spp., Cryptococcus spp., Fusarium spp., Histoplasma spp., Mucorales spp., Pneumocystis spp., Trichophyton spp., Epidermophyton spp., Microsporum spp, Sporothrix spp., Exserohilum spp., and Cladosporium spp.
(107) Parasites. The methods disclosed herein can also be used to inactivate parasites (e.g., intracellular parasites) for highly immunogenic vaccines, and especially protozoan parasites, such as Plasmodium falciparum and other Plasmodium spp., Leishmania spp., Cryptosporidium parvum, Entamoeba histolytica, and Giardia lamblia, Trypanosoma spp., as well as Toxoplasma, Eimeria, Theileria, and Babesia species.
(108) Immunogenic Compositions
(109) Using the disclosed methods, immunogenic compositions, such as vaccines containing an inactivated pathogen as also provided. For example, the composition (or medicament) can be a lyophilized immunogenic composition (for example, vaccine preparation) containing a pathogen that retains one or more predominant antigenic epitopes of the biologically active pathogen from which it was prepared. The lyophilized composition may be prepared preservative-free and devoid of any inactivating agent (e.g., devoid of H.sub.2O.sub.2, etc.). The composition can also be a liquid prepared by reconstituting a lyophilized composition in a pharmaceutically acceptable diluent. Optionally, the composition can include a suitable adjuvant that increases the antigenic efficacy of the antigen.
(110) Inactivation with the presently disclosed dual oxidation approach, and including those further comprising use of a methisazone reagent, not only provides improved methods for vaccine production, including for pathogens for which effective vaccines cannot be produced by other methods (including by peroxide alone), but also provides several additional significant benefits as compared to UV inactivation, heat inactivation or inactivation with formaldehyde or betapropiolactone.
(111) First, dual oxidation with hydrogen peroxide plus transition metals ions (Fenton type reaction), and including dual oxidation further comprising use of a methisazone reagent, is significantly better than any of the other methods at maintaining immunogenic epitopes. Thus, dual oxidation inactivation, and including dual oxidation further comprising use of a methisazone reagent, produces highly effective immunogenic compositions, such as vaccines, which can be used to produce an immune response that is far more likely to be protective against subsequent infection by the live pathogen than are vaccines produced using methods that denature or destroy immunologically important epitopes.
(112) Second, unlike other chemical inactivating agents, such as formaldehyde or betapropiolactone, the Cu and Fe ions used in the presently disclosed dual oxidation methods are not only naturally occurring in subjects, but are present in the reactions in non-toxic amounts. Moreover, residual transition metals, and/or methisazone reagents, can be removed by downstream purification using, for example, anion exchange chromatography, flow filtration (e.g., tangential flow filtration), size exclusion chromatography, desalting columns, diafiltration, dialysis, ultracentrifugation, sucrose gradient purification, high pressure liquid chromatography (HPLC), etc.
(113) Likewise, any residual hydrogen peroxide can be substantially or completely removed from the vaccine composition by either using subsequent purification steps as described above for optional transition metal removal, or by using lyophilization. For example, a solution containing a pathogen and hydrogen peroxide and transition metal ions can be dispensed into sterile vials and lyophilized. During the lyophilization process, hydrogen peroxide is removed in vapor form, leaving behind a stable and sterile vaccine composition, which can easily be stored until it is needed. Lyophilization removes some, most or even all detectable hydrogen peroxide from the vaccine composition, and where desired produces a vaccine composition that is substantially free of hydrogen peroxide. Lyophilization can be performed by essentially any methods known in the art so long as the temperature is maintained below that at which heat denaturation of immunogenic epitopes occurs. Thus, the lyophilization can be performed following pre-freezing of the hydrogen peroxide/pathogen solution) or without pre-freezing (for example, at ambient temperatures above freezing, e.g., using a SPEED-VAC® concentrator under conditions that maintain the ambient temperature between about 0-4° C. and about 42° C.). For the purpose of manufacturing immunogenic compositions, such as vaccines, for administration to human or animal subjects, lyophilization is typically carried out according to current good manufacturing procedures (cGMP) for the production of vaccines. The inactivation and lyophilization can be accomplished without any intervening processing step, such as dilution, dialization, centrifugation, or purification. So long as the pathogen/hydrogen peroxide solution is dispensed (or aliquoted) into clean, sterile containers (e.g., vial, ampules, tubes, etc.) prior to lyophilization, the resulting vaccine composition is sterile, and no additional preservative need be added prior to administration. For example, if the vaccine composition is to be administered. in a single dose, the lyophilized vaccine composition is simply suspended (or dissolved) in a pharmaceutically acceptable diluent to produce a preservative-free liquid vaccine composition. In the event that the lyophilized vaccine composition is intended for multiple administrations (for example, multiple sequential administration to a single subject, or one or more administrations to multiple subjects) the diluent can include a pharmaceutically acceptable preservative.
(114) If desired, transition metal ions and/or hydrogen peroxide can be removed by purification steps as described above. For example, residual H.sub.2O.sub.2 and transition metals (e.g., either Cu or Fe) can be removed by use of one or more purification approaches such as tangential flow filtration, dialysis, desalting columns, ion-exchange chromatography (under conditions that bind the virus but not the residual inactivation components), affinity chromatography, size exclusion chromatography, etc.
(115) Alternatively, sodium bisulfite (NaHSO.sub.3) and/or sodium metabisulfite (Na.sub.2S.sub.2O.sub.5) can both be used to neutralize H.sub.2O.sub.2 (1 mol of metabisulfite breaks down to two mols of bisulfite, which then reacts directly with H.sub.2O.sub.2).
Na.sub.2S.sub.2O.sub.5+2H.sub.2O.fwdarw.2NaHSO.sub.3+H.sub.2O (1)
2NaHSO.sub.3+2H.sub.2O.sub.2.fwdarw.2NaHSO.sub.4+2H.sub.2O (2)
(116) Prior to use, the vaccine can be reconstituted using a pharmaceutically acceptable diluent to facilitate delivery by conventional administration means. This enables the production of a sterile vaccine composition that does not contain harmful amounts of toxic and carcinogenic compounds, thereby increasing the safety of the vaccine.
(117) Additionally, following dual oxidation inactivation, or dual oxidation further comprising use of a methisazone reagent, there is no need to add a preservative (such as thimerosal) to the resulting vaccine composition. The sterile composition can be maintained for long periods of time (e.g., in the lyophilized state), making addition of potentially toxic preservatives unnecessary. Thus, the compositions can be made to be substantially or completely free of preservatives. Optionally, preservatives can be provided in the composition.
(118) The dual oxidation methods, and including those further comprising use of a methisazone reagent, provide immunogenic compositions, such as a vaccine, and thus provide methods for preparing a medicament that includes an inactivated pathogen. The methods provide compositions that contain an immunologically active noninfectious pathogen that retains predominant immunological epitopes of the infectious pathogen from which it is produced. Typically, the inactivated pathogen retains one, or more than one, immunologically dominant epitopes that elicit a protective immune response against the pathogen. This method is suitable for producing an immunogenic composition (for example, a vaccine) containing inactivated pathogens, including viruses, bacteria, fungi and parasites, such as intracellular parasites (for example, protozoan parasites). Optionally, the compositions contain more than one species or strain of pathogen, for example, combination vaccines can be produced using the methods. The compositions can include a plurality of viruses, e.g., mumps virus, measles virus and rubella virus, and/or other viruses as disclosed herein. Similarly, the composition can include a plurality of bacteria, e.g., Campylobacter species (spp.), Corynebacterium diphtheriae, Bordetella pertussis and Clostridium tetani, the causative agents of diarrhea, diphtheria, whooping cough and tetanus, respectively, and/or other bacterial as disclosed herein. The composition can also include a plurality of pathogens selected from different classifications (families) of organisms.
(119) The dual oxidation methods involve contacting the pathogen with a solution containing an effective amount of the dual oxidizing agent (e.g., Fenton reagents; hydrogen peroxide (H.sub.2O.sub.2) plus transition metal ions), or with the dual oxidizing agent and a methisazone reagent, for a period sufficient to render the pathogen noninfectious. Optionally, the pathogen is purified or isolated prior to contacting with the dual oxidizing agent.
(120) Typically, the solution includes at least about 0.001% or 0.002% hydrogen peroxide (wt/vol), and may contain up to about 0.10% hydrogen peroxide. Typically, the solution includes at least 1 μM or 2 μM transition metal (e.g., CuCl.sub.2). Most typically, at least 0.001% or 0.002% hydrogen peroxide (wt/vol) is used in combination with at least 1 μM or 2 μM transition metal (e.g., CuCl.sub.2). For example, the solution can include about 0.002% hydrogen peroxide (wt/vol), and about 1 μM or 2 μM CuCl.sub.2. In further embodiments, the hydrogen peroxide concentration can be as low as 0.0001%, or as high 1.0%, in combination with above-described levels of transition metal. The concentration range of transition metals can be as low as 0.001 μM, or as high as 1000 μM, again with any of the disclosed levels of hydrogen peroxide. In reactions comprising a methisazone reagent, the preferred amount of methisazone reagent, methisazone analogs, or chemicals representing methisazone functional groups or methisazone functional substructures can be as low as 0.01 μM, or as high as 10,000 μM with any of the disclosed levels of hydrogen peroxide or transition metals.
(121) While the mechanism of the dual-oxidation inactivation was found to be surprisingly different (i.e., found to be protein concentration-dependent) than that of simple hydrogen peroxide mediated oxidation, present Applicants have nonetheless found that the absolute and/or relative amounts of hydrogen peroxide (wt/vol) and transition metal ions (e.g., CuCl.sub.2) can be varied and adjusted to optimize inactivation while retaining immunogenicity for a broad array of pathogens. Applicants have found that having two variables (hydrogen peroxide concentration; and transition metal concentration) to vary, and even three variables in reaction using a methisazone reagent, provides an enhanced fine tuning ability over prior art methods using a single agent. Moreover, Applicants have surprisingly found (as shown herein under the working examples), that the two Fenton components (hydrogen peroxide concentration; and transition metal concentration), as well as the methisazone reagents in reactions including them, act in synergy to provide results not achievable using single agents alone. Additionally, combinations of transition metals (e.g., CuCl.sub.2 (Cu.sup.2+), FeCl.sub.3 (Fe.sup.3+) or CsCl (Cs.sup.+)), and methisazone reagents can be employed to exploit synergistic effects. For example, at CuCl.sub.2 concentrations of 0.05 μM and 0.10 μM, increasing FeCl.sub.3 concentrations enhanced antigenicity, indicating synergy with these two metals. These fine-tuning and synergistic aspects support a broad utility for the presently disclosed dual oxidation approach.
(122) The length of time sufficient to completely inactivate a pathogen can vary between several minutes and several hours. For example, the pathogen can be contacted with the dual oxidation solution, or the dual oxidation solution further comprising a methisazone reagent, for a time within a range of about 1 hour to 24 hours, or shorter periods. Typically, for dual oxidation reactions, about 20 hours (plus or minus 2 hours) is used when using at least 0.001% or 0.002% hydrogen peroxide (wt/vol) is used in combination with at least 1 μM or 2 μM transition metal (e.g., CuCl.sub.2). Generally, the length of time sufficient to inactivate the pathogen is dependent on the particular pathogen, and the concentration of reagents, and one of ordinary skill in the art will be able to empirically determine the concentration of reagents, the length of reaction time required, and the reaction temperature, based on the present disclosed teachings. In further embodiments, the hydrogen peroxide concentration can be as low as 0.0001%, or as high as 1.0%, in combination with above-described levels of transition metal. The concentration range of transition metals can be as low as 0.001 μM, or as high as 1000 μM, again with any of the disclosed levels of hydrogen peroxide. The preferred concentration of the methisazone reagent, methisazone analogs, or chemicals representing methisazone functional groups or methisazone functional substructures can be as low as 0.01 μM, or as high as 10,000 μM with any of the disclosed levels of hydrogen peroxide or transition metals.
(123) The pathogen inactivation can be carried out at any temperature between freezing and the temperature at which immunologically relevant epitopes are denatured. Most commonly, the inactivation process is carried out at or above 4° C. and below about 42° C. For example, it is often convenient to perform the inactivation at room temperature or about 25° C.
(124) Generally speaking, the dual oxidation conditions, including those further comprising a methisazone reagent, are determined to provide a high safety margin during the manufacturing process (e.g., up to 100 million-fold theoretical excess inactivation) while still maintaining overall antigenic structure.
(125) The inactivated pathogen can then be stored for prolonged periods (for example, for more than several months or more than 1 year). The solution containing the inactivated pathogen can then be administered directly to a subject for the purpose of eliciting an immune response against the pathogen, for example, as a vaccine. More commonly, the solution including the inactivated pathogen is further processed or lyophilized, as described above, to produce an immunogenic composition.
(126) The disclosure, therefore, provides immunogenic (e.g., vaccine) compositions produced according to the methods disclosed herein. For example, the composition (e.g., a medicament) is a lyophilized and/or purified composition including an inactivated pathogen that retains one or more predominant antigenic epitope of the biologically active pathogen. Typically, the composition is substantially or completely free of any preservative or inactivating agent, such as hydrogen peroxide, formaldehyde or betapropiolactone. In another embodiment, the composition is a liquid produced by suspending or dissolving (solubilizing) the lyophilized, or purified composition in a pharmaceutically acceptable diluent. Optionally, the diluent contains a preservative. Optionally, the vaccine composition includes an adjuvant. In lyophilized form, the adjuvant can be, for example, an aluminum (e.g., alum or an aluminum salt) adjuvant. Upon preparation of a liquid formulation from the lyophilized vaccine composition, the adjuvant can be a lipid formulation (e.g., an oil capable of forming an emulsion). The inactivated pathogen genome may comprise RNA or DNA.
(127) Methods for Eliciting an Immune Response in a Subject by Administering the Compositions Containing Inactivated Pathogen are Also Provided
(128) According to additional aspects, methods of eliciting an immune response against a pathogen by administering the immunogenic compositions are provided. Typically, the immune response is a protective immune response that prevents or reduces infection by one or more pathogens. For example, an immune response can be elicited in a subject by preparing a composition by contacting a pathogen with a solution containing the dual oxidation reagent(s) for a period sufficient to render the pathogen noninfectious (while retaining immunogenicity); and administering the composition to a subject, thereby eliciting in the subject an immune response (e.g., a protective immune response) against the pathogen. In some applications the solution is administered to a subject without removing dual oxidation agent(s) from the solution. In other applications, the composition is lyophilized and/or otherwise purified as described herein, removing some or all (or substantially all) of the dual oxidation reagent(s). The processed composition can be administered in powder form (for example, as a dispersed powder or as a pellet, e.g., using the POWDERJECT® transdermal powder injection device). Alternatively, the lyophilized composition is reconstituted in a pharmaceutically acceptable diluent for administration using any method suitable for delivering a vaccine to a subject, e.g., intramuscular, intradermal, transdermal, subcutaneous or intravenous injection, oral delivery, or intranasal or other mucosal delivery of the immunogenic composition (e.g., vaccine).
(129) Terms
(130) Unless otherwise explained, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. Definitions of common terms in molecular biology may be found in Benjamin Lewin, Genes V, published by Oxford University Press, 1994 (ISBN 0-19-854287-9); Kendrew, et al. (eds.), The Encyclopedia of Molecular Biology, published by Blackwell Science Ltd., 1994 (ISBN 0-632-02182-9); and Robert A. Meyers (ed.), Molecular Biology and Biotechnology: a Comprehensive Desk Reference, published by VCH Publishers, Inc., 1995 (ISBN 1-56081-569-8).
(131) The singular terms “a,” “an,” and “the” include plural referents unless context clearly indicates otherwise. Similarly, the word “or” is intended to include “and” unless the context clearly indicates otherwise.
(132) Although methods and materials similar or equivalent to those described herein can be used in the practice or testing of this disclosure, suitable methods and materials are described below. The term “comprises” means “includes.” The abbreviation. “e.g.” is derived from the Latin exempli gratis, and is used herein to indicate a non-limiting example. Thus, the abbreviation “e.g.” is synonymous with the term “for example.
(133) In order to facilitate review of the various embodiments of his disclosure, the following explanations of specific terms are provided:
(134) “An immunogenic composition” or “vaccine composition” or “vaccine” is a composition of matter suitable for administration to a human or animal subject that is capable of eliciting a specific immune response, e.g., against a pathogen. As such, an immunogenic composition or vaccine includes one or more antigens or antigenic epitopes. The antigen can be in the context of an isolated protein or peptide fragment of a protein, or can be a partially purified preparation derived from a pathogen. Alternatively, the antigen can be in the context of a whole live or inactivated pathogen. Typically, when an immunogenic composition or vaccine includes a live pathogen, the pathogen is attenuated, that is, incapable of causing disease in an immunologically competent subject. In other cases, an immunogenic composition or vaccine includes a whole inactivated (or killed) pathogen. The inactivated pathogen can be either a wild-type pathogenic organism that would otherwise (if not inactivated) cause disease in at least a portion of immunologically competent subjects, or an attenuated or mutant strain or isolate of the pathogen. In the context of this disclosure, the immunogenic and/or vaccine compositions contain a whole (wild-type, attenuated or mutant) pathogen.
(135) An “immune response” is a response of a cell of the immune system, such as a B cell, T cell, or monocyte, to a stimulus. In some cases, an immune response is a T cell response, such as a CD4+ response or a CD8+ response. Alternatively, the response is a B cell response, and results in the production of specific antibodies. In some cases, the response is specific for a particular antigen (that is, an “antigen-specific response”). If the antigen is derived from a pathogen, the antigen-specific response is a “pathogen-specific response.” A “protective immune response” is an immune response that inhibits a detrimental function or activity of a pathogen, reduces infection by a pathogen, or decreases symptoms (including death) that result from infection by the pathogen. A protective immune response can be measured, for example, by the inhibition of viral replication or plaque formation in a plaque reduction assay or ELISA-neutralization assay, or by measuring resistance to viral challenge in vivo.
(136) An “immunologically effective amount” is a quantity of a composition used to elicit an immune response in a subject. In the context of a vaccine administration, the desired result is typically a protective pathogen-specific immune response. However, to obtain protective immunity against a pathogen in an immunocompetent subject, multiple administrations of the vaccine composition are commonly required. Thus, in the context of this disclosure, the term immunologically effective amount encompasses a fractional dose that contributes in combination with previous or subsequent administrations to attaining a protective immune response.
(137) An “antigen” is a compound, composition, or substance that can stimulate the production of antibodies and/or a T cell response in an animal, including compositions that are injected, absorbed or otherwise introduced into an animal. The term “antigen” includes all related antigenic epitopes. The term “epitope” or “antigenic determinant” refers to a site on an antigen to which B and/or T cells respond.
(138) The “predominant antigenic epitopes” are those epitopes to which a functionally significant host immune response, e.g., an antibody response or a T-cell response, is made. Thus, with respect to a protective immune response against a pathogen, the predominant antigenic epitopes are those antigenic moieties that when recognized by the host immune system result in protection from disease caused by the pathogen.
(139) The term “antigenicity” refers to the relative maintenance of immunogenic epitope structure(s) as determined, for example, by various in vitro measurements, such as binding of specific monoclonal antibodies or hemagglutination assays. “Antigenicity” in the in vivo context is typically referred to herein as “immunogenicity”.
(140) An “adjuvant” is an agent that enhances the production of an immune response in a non-specific manner. Common adjuvants include suspensions of minerals (e.g., alum, aluminum hydroxide, aluminum phosphate) onto which antigen is adsorbed; or water-in-oil emulsions in which an antigen solution is emulsified in oil (MF-59, Freund's incomplete adjuvant). Additional details regarding various adjuvants can be found in Derek O'Hagan Vaccine Adjuvants: Preparation Methods and Research Protocols (Methods in Molecular Medicine) Humana Press, 2000.
(141) The term “pathogen” as used herein refers to an organism having either an RNA or DNA genome, and encompasses viruses (both RNA and DNA genome-based), bacteria (DNA genome-based, both Gram-positive and Gram-negative), fungi, and parasites. In particular preferred aspects, “pathogen” refers to an organism having either an RNA or DNA genome, and encompasses viruses (both RNA and DNA genome-based), and bacteria (DNA-genome based, both Gram-positive and Gram-negative).
(142) The term “whole pathogen” refers to a pathogenic organism, such as a virus, a bacterium, a fungus or a parasite, that includes all or substantially all of the constituents of the infectious form of the organism. Typically, a whole pathogen is capable of replication. The term “whole pathogen” is nonetheless distinct from the term “wild-type” pathogen, and the term “whole pathogen” encompasses wild-type as well as attenuated and other mutant forms of the pathogenic organism. Thus, a whole pathogen can be an attenuated pathogen incapable of causing disease in an immunocompetent host, but nonetheless including all or substantially all of the constituents of an infectious pathogen. Similarly, a whole pathogen can be a mutant form of the pathogen, lacking one or more intact (wild-type) genes, and/or proteins. The pathogen genome may comprise RNA or DNA.
(143) An “inactivated pathogen” is a whole pathogen that has been rendered incapable of causing disease (e.g., rendered noninfectious) by artificial means. Typically, an inactivated pathogen is a “killed pathogen” that is incapable of replication. A pathogen is noninfectious when it is incapable of replicating or incapable of replicating to sufficient levels to cause disease.
(144) An “immunogenically active vaccine”, as used herein in connection with Applicants' methods, is a pathogen inactivated by the disclosed methods that is capable of eliciting an immune response when introduced into an immunologically competent subject. The immune response produced in response to exposure to an immunogenically active vaccine comprising the inactivated pathogen as disclosed herein is preferably identical, substantially identical, or superior with respect to that produced by the predominant antigenic epitopes of the respective infectious pathogen.
(145) “Hydrogen peroxide” (H.sub.2O.sub.2) is an exemplary preferred oxidizing agent with a standard electrode potential of 1.78 volts. For the purpose of consistency, the proportion of hydrogen peroxide in a solution, as in the working Examples disclosed herein, is given as weight per volume (wt/vol). For example 0.01% H.sub.2O.sub.2 refers to H.sub.2O.sub.2 being present at 0.01% wt/vol.
(146) A “dual oxidizing agent” as used herein refers to a Fenton-type dual oxidation reagent comprising hydrogen peroxide and at least one transition metal (e.g., CuCl.sub.2 (Cu.sup.2+), FeCl.sub.3 (Fe.sup.3+) or CsCl (Cs.sup.+)).
(147) A “solution comprising the dual oxidizing agent(s)” includes the combination of any mixture of a solvent and dual oxidizing agent(s). Most commonly, in the context of the methods disclosed herein the solvent is water, e.g., deionized water, or an aqueous buffered salt solution. Typically, the term solution includes liquid phase solutions. For the purpose of consistency, the proportion of hydrogen peroxide in a solution is given as weight per volume (wt/vol).
(148) The phrase “substantially free of hydrogen peroxide” indicates that no more than trace amounts (amounts empirically detectable as background) are present in the composition.
(149) The verb “lyophilize” means to freeze-dry under vacuum. The process is termed “lyophilization.” In some cases, the sample to be dried (e.g., dehydrated) is frozen prior to drying. In other cases, the material to be dried is subjected to the drying process without prior phase change. During the process of lyophilization, evaporation of the solvent results in cooling of the sample to temperatures below the melting temperature of the solvent/solute mixture resulting in freezing of the sample. Solvent is removed from the frozen sample by sublimation. A product that has undergone lyophilization is “lyophilized.” As used in this disclosure the term lyophilization also encompasses functionally equivalent procedures that accelerate the drying process without exposing the sample to excessive heat, specifically including: spray drying and spray freeze-drying.
(150) The term “methisazone” and “methisazone analog” as used herein in particular aspects refers to compounds having the following formula:
(151) ##STR00008##
wherein R.sub.1 is independently H or lower alkyl (e.g., C1-C4 alkyl) optionally substituted with —OH, for example, wherein R.sub.1 is H, —CH.sub.3, or propyl, etc.; wherein R.sub.2 is independently H, lower alkyl (e.g., C1-C2 alkyl) optionally substituted with —OH, or aryl; wherein X is independently H or halogen (e.g., I, Br, Cl, F); and salts, including pharmaceutically acceptable salts, thereof. Preferably, wherein X and R.sub.2 are H; and wherein R.sub.1 is H (isatin β-thiosemicarbazone), —CH.sub.3 (N-methyl-isatin β-thiosemicarbazone (methisazone)), or propyl (N-propyl-isatin β-thiosemicarbazone). Preferably, methisazone is used:
(152) ##STR00009##
(153) The term “methisazone functional group” or “methisazone functional substructure” as used herein in particular aspects refers to compounds having the following formulae:
(154) ##STR00010##
wherein R.sub.1 is H or lower alkyl (e.g., C1-C4 alkyl) optionally substituted with —OH, for example, wherein X is H and wherein R.sub.1 is (isatin) or —CH.sub.3 (N-methyl-isatin), or propyl (N-propyl-isatin), etc.; wherein X is independently H or halogen (e.g., I, Br, Cl, F); and salts, including pharmaceutically acceptable salts, thereof;
(155) ##STR00011##
wherein R.sub.1 is H or lower alkyl (e.g., C1-C4 alkyl) optionally substituted with —OH, for example, wherein X is H and wherein R.sub.1 is H (indole, 2,3-dione, 3-hydrazone) etc.; wherein X is independently H or halogen (e.g., I, Br, Cl, F); wherein R.sub.2 is independently H, lower alkyl (e.g., C1-C2 alkyl) optionally substituted with —OH, or aryl; and salts, including pharmaceutically acceptable salts, thereof; and
(156) ##STR00012##
wherein R.sub.2 and R.sub.3 are independently H, lower alkyl (e.g., C1-C2 alkyl) optionally substituted with —OH, or aryl; and salts, including pharmaceutically acceptable salts, thereof; and combinations thereof.
(157) In particular aspects, the following combinations of “methisazone functional group” or “methisazone functional substructure” are used:
(158) ##STR00013##
wherein R.sub.1 is H or lower alkyl (e.g., C1-C4 alkyl), for example, wherein R.sub.1 is H (isatin) or —CH.sub.3 (N-methyl-isatin), or propyl (N-propyl-isatin), etc., and salts, including pharmaceutically acceptable salts, thereof.
(159) In particular aspects, the following combination of “methisazone functional groups” or “methisazone functional substructures” is used:
(160) ##STR00014##
(161) In the context of this disclosure “room temperature” refers to any temperature within a range of temperatures between about 16° C. (approximately 61° F.) and about 25° C. (approximately 77° F.). Commonly, room temperature is between about 20° C. and 22° C. (68° F.-72° F.). Generally, the term room temperature is used to indicate that no additional energy is expended cooling (e.g., refrigerating) or heating the sample or ambient temperature.
(162) A “preservative” is an agent that is added to a composition to prevent decomposition due to chemical change or microbial action. In the context of vaccine production, a preservative is typically added to prevent microbial (e.g., bacterial and fungal) growth. The most common preservative used in vaccine production is thimerosal, a mercury containing organic compound. Thus, the term “preservative-free” indicates that no preservative is added to (or present in) the composition.
(163) The term “purification” (e.g., with respect to a pathogen or a composition containing a pathogen) refers to the process of removing components from a composition, the presence of which is not desired. Purification is a relative term, and does not require that all traces of the undesirable component be removed from the composition. In the context of vaccine production, purification includes such processes as centrifugation, dialization, ion-exchange chromatography, and size-exclusion chromatography, affinity-purification, precipitation and other methods disclosed herein (e.g., lyophilization, etc). Such purification processes can be used to separate the inactivated pathogen components from the reagents used to inactivate the respective pathogen as disclosed herein. For example hydrogen peroxide, metal reagents, “methisazone”, “methisazone analogs” “methisazone functional groups” or “methisazone functional substructures” can be separated from the inactivated pathogen components to provide purified vaccine compositions. For example, residual methisazone, methisazone analogs, or chemicals representing methisazone functional groups or methisazone functional substructures may range from 0.0001 to 10 mM when used for vaccine antigen preparation. A range of standard purification techniques may be used to remove or separate these residual components from vaccine antigen prior to final formulation, including, but not limited to, affinity chromatography, ion-exchange chromatography, mixed-mode/multimodal chromatography, gel filtration/size-exclusion chromatography, desalting chromatography, tangential flow filtration/diafiltration, density-gradient centrifugation, centrifugal filtration, dialysis, vaccine antigen precipitation or vaccine antigen adsorption.
(164) The adjective “pharmaceutically acceptable” indicates that the subject is physiologically acceptable for administration to a subject (e.g., a human or animal subject). Remington's Pharmaceutical Sciences, by E. W, Martin, Mack Publishing Co., Easton, Pa., 15th Edition (1975), describes compositions and formulations (including diluents) suitable for pharmaceutical delivery of therapeutic and/or prophylactic compositions, including vaccines.
(165) In general, the nature of the diluent will depend on the particular mode of administration being employed. For instance, parenteral formulations usually comprise injectable fluids that include pharmaceutically and physiologically acceptable fluids such as water, physiological saline, balanced salt solutions, aqueous dextrose, glycerol or the like as a vehicle. In certain formulations (for example, solid compositions, such as powder, pill, tablet, or capsule forms), a liquid diluent is not employed. In such formulations, non-toxic solid carriers can be used, including for example, pharmaceutical grades of mannitol, lactose, starch or magnesium stearate.
(166) The phrase “Good Manufacturing Practice” or “GMP” with respect to methods and procedures employed in vaccine production refer specifically to the set of methods, protocols and procedures established by the United States Food and. Drug Administration (FDA). Similar recommendations and guidelines are promulgated by the World Health Organization. The abbreviation “cGMP” specifically designates those protocols and procedures that are currently approved by the FDA (e.g., under 21 Code of Federal Regulations, parts 210 and 211, available on the world wide web at fda.gov/cder/dmpq). With time cGMP compliant procedures may change. Any methods disclosed herein can be adapted in accordance with new cGMP requirements as mandated by the FDA.
(167) Inactivation of Pathogens
(168) To inactivate a pathogen using dual oxidizing agent(s), including those further comprising a methisazone reagent, the live pathogen is grown to a desired density (e.g., saturation density in culture), according to any procedures acceptable in the art for growing (e.g., culturing the specific organism). Typically, for cellular pathogens, it is desirable to culture the pathogen to stationary phase; as such organisms are generally more resistant to stresses in subsequent processing than those harvested at logarithmic phase. Growth in culture can be monitored using methods known in the art, such as measuring optical density of the culture using spectrophotometry. When the pathogen is a virus, growth can monitored by titering the virus using standard methods established for the selected virus. For example, methods for growing animal viruses can be found, for example, in DNA Viruses: A Practical Approach, Alan J. Cann (ed.) Oxford University Press, 2000; Robinson and Cranage (eds.) Vaccine Protocols (Methods in Molecular Medicine) Humana Press, 2003, and references cited therein. Methods for culturing pathogenic bacteria are also known in the art, and can be found in Molecular Cloning: A Laboratory Manual, 2nd ed., vol. 1-3, ed. Sambrook, et al., Cold Spring Harbor Laboratory Press, Cold Spring Harbor, N.Y., 1989. Methods for culturing parasites, such as malaria, are also known in the art, e.g., Denise Doolan (ed.) Malaria Methods and Protocols (Methods in Molecular Medicine) Humana Press, 2002, and references cited therein.
(169) Typically, the pathogenic organisms can have RNA or DNA genomes (e.g., viruses, bacteria, fungus, or parasites) and are purified from the medium in which they are grown or cultured, and in the case of pathogens that replicate inside a cell are purified from the other cellular components. For example, the relative concentration of non-pathogen components of a suspension including pathogens can be decreased by at least 50%, such as about 70%, or by as much as 80%, or even by 90%, 95% or more, relative to a crude preparation of pathogen. Intracellular pathogens, such as viruses, can be isolated or purified from the various components of the cells they infect by various methods known in the art.
(170) For example, viruses for vaccine production are typically grown under controlled conditions in a certified cell line using biologically and chemically defined culture medium according to cGMP procedures. Cells are usually infected with virus at an appropriate multiplicity of infection (MOI), and the cells are maintained in culture under conditions and for a period of time sufficient to permit replication of the virus to high titer. The cells are then harvested by centrifugation (following release from the culture surface in the case of adherent cells), and resuspended in an appropriately buffered solution. To facilitate recovery, the buffered solution is typically hypotonic with respect to the cells, causing the cells to swell. Optionally, the cell suspension is agitated periodically to ensure a more uniform exposure of the cells to the hypotonic solution. The cells are then lysed, for example, by homogenization, to release the virus. The lysate is centrifuged to remove large particulate matter, such as cell nuclei, and the supernatant is filtered to remove additional cellular debris. The virus can then be further purified by layering the filtered supernatant onto a suitable separation medium, such as a sucrose density gradient. Optionally, the nuclear pellet can be further processed to increase viral yield. The nuclear pellet is resuspended again in hypotonic buffer and homogenized. The nuclear lysate is centrifuged and the resulting supernatant is filtered prior to layering onto separation medium. Optionally, the two viral suspensions are combined to achieve an approximately equal volume separation gradient. The separation medium/virus suspension is then processed by ultracentrifugation (e.g., at 55,000×g for 1-1.5 hours at 4° C. Virus is collected into a pellet by this process whereas membranous cellular debris remains at the interface. The supernatant is removed (typically by aspiration) and the pellet is resuspended in buffer. The purified virus can then be evaluated for recovery and viability (for example by determining protein concentration and by plaque assays, respectively). If desired the recovered virus can be frozen and stored until use.
(171) Similar procedures are known in the art for purifying non-viral pathogens, such as intracellular parasites (for example, protozoan parasites, including Plasmodium falciparum and other Plasmodium species, Leishmania (sp.), Cryptosporidium parvum, Entamoeba histolytica, and Giardia lamblia, as well as Toxoplasma, Eimeria, Theileria, and Babesia species).
(172) Reconstitution and Administration
(173) Immunogenic compositions, such as vaccines, that are produced as powders (e.g., lyophilized powders) are typically mixed with a liquid for administration. This process is known as “reconstitution,” and the liquid used is commonly referred to as a “diluent.” For purposes of administration, especially to human subjects, it is important that the diluent be a pharmaceutically acceptable formulation. Reconstitution of the lyophilized composition is typically carried out using a sterile syringe and needle for each vial of diluent. The correct diluent for each type and batch is used to ensure adequate potency, safety and sterility of the resulting mixture. Diluents are specifically designed to optimize delivery and efficacy of the selected composition. Common diluents include such additives as: stabilizers to improve heat stability of the vaccine; agents, such as surfactants, to assist in dissolving the powder into a liquid; and buffers to ensure the correct acidic balance of the reconstituted composition. Optionally, the diluent can contain a preservative (e.g., a bactericide and/or a fungicide) to maintain sterility after reconstitution. Preservatives are typically required (e.g., by the FDA) when the composition is reconstituted in a multi-dose formulation.
(174) Administration of Immunogenic Compositions Such as Vaccines (Therapeutic Methods)
(175) The immunogenic compositions (such as vaccine or other medicaments) disclosed herein can be administered to a subject to elicit an immune response against a pathogen. Most commonly, the compositions are administered to elicit a prophylactic immune response against a pathogenic organism to which the subject has not yet been exposed. For example, vaccine compositions including dual oxidation-inactivated pathogens can be administered as part of a localized or wide-spread vaccination effort. An immune response elicited by administration of such vaccine compositions typically includes a neutralizing antibody response, and can in addition include a T cell response, e.g., a cytotoxic T cell response that targets cellular pathogens. Accordingly, methods for making a medicament or pharmaceutical composition containing dual oxidation-inactivated pathogens are included herein. The pharmaceutical compositions (medicaments) include at least one pathogen inactivated by contact with a solution containing the dual oxidizing agent(s), or by contact with the dual oxidizing agents further comprising a methisazone reagent, in a pharmaceutically acceptable carrier or excipient.
(176) In some cases, the immunogenic composition can include a combination of pathogens, such as a combination of viruses (for example mumps virus, measles virus, rubella virus), or a combination of bacteria (for example, Campylobacter species (spp.), Corynebacterium diptheriae, Bordatella pertussis, and Clostridium tetani), or a combination of pathogens selected from different classes of organisms, e.g., one or more viruses and one or more bacteria, one or more bacteria and one or more parasites, and the like.
(177) The quantity of pathogen included in the composition is sufficient to elicit an immune response when administered to a subject. For example, when administered to a subject in one or more doses, a vaccine composition containing an inactivated pathogen favorably elicits a protective immune response against the pathogen. A dose of the vaccine composition can include at least about 0.1% wt/wt inactivated pathogen to about 99% wt/wt inactivated pathogen, with the balance of the vaccine composition is made up of pharmaceutically acceptable constituents, such as a pharmaceutically acceptable carrier and/or pharmaceutically acceptable diluent. Guidelines regarding vaccine formulation can be found, e.g., in U.S. Pat. Nos. 6,890,542, and 6,651,655. In one specific, non-limiting example the vaccine composition (medicament) includes at least about 1%, such as about 5%, about 10%, about 20%, about 30%, or about 50% wt/wt inactivated pathogen. As will be apparent to one of ordinary skill in the art, the quantity of pathogen present in the vaccine formulation depends on whether the composition is a liquid or a solid. The amount of inactivated pathogen in a solid composition can exceed that tolerable in a liquid composition. The amount of inactivated pathogen can alternatively be calculated with respect to the comparable amount of a live or inactivated pathogen required to give an immune response. For example, a dosage equivalent in viral particles to from about 10.sup.6 to about 10.sup.12 plaque forming units (PFU) of live or attenuated virus can be included in a dose of the vaccine composition. Similarly, a vaccine composition can include a quantity of inactivated pathogen (e.g., with RNA or DNA genome), such as virus, bacteria, fungus or parasite equivalent to between about 10.sup.3 to about 10.sup.10 live organisms. Alternatively, the dosage can be provided in terms of protein content or concentration. For example, a dose can include from approximately 0.1 μg, such as at least about 0.5 μg protein. For example, a dose can include about 1 μg of an isolated or purified virus or other pathogen up to about 100 μg, or more of a selected pathogen. Although the equivalent doses in infectious units (e.g., PFU) can vary from pathogen to pathogen, the appropriate protein dose can be extrapolated (for example, from PFU) or determined empirically. For example, in a typical preparation, 1 μg of purified vaccinia virus is equivalent to approximately 2×10.sup.6 PFU. Similar conversions can be determined for any pathogen of interest.
(178) Typically, preparation of a vaccine composition (medicament) entails preparing a pharmaceutical composition that is essentially free of pyrogens, as well as any other impurities that could be harmful to humans or animals. Typically, the pharmaceutical composition contains appropriate salts and buffers to render the components of the composition stable and allow for appropriate processing and presentation of the vaccine antigen by antigen presenting cells. Such components can be supplied in lyophilized form, or can be included in a diluent used for reconstitution of a lyophilized form into a liquid form suitable for administration. Alternatively, where the inactivated pathogen is prepared for administration in a solid state (e.g., as a powder or pellet), a suitable solid carrier is included in the formulation.
(179) Aqueous compositions typically include an effective amount of the inactivated pathogen dispersed (for example, dissolved or suspended) in a pharmaceutically acceptable diluent or aqueous medium. The phrase “pharmaceutically acceptable” refers to molecular entities and compositions that do not produce an adverse, allergic or other undesirable reaction when administered to a human or animal subject. As used herein, “pharmaceutically acceptable carrier” includes any and all solvents, dispersion media, coatings, isotonic and absorption delaying agents and the like. Optionally, a pharmaceutically acceptable carrier or diluent can include an antibacterial, antifungal or other preservative. The use of such media and agents for pharmaceutically active substances is well known in the art. Except insofar as any conventional media or agent is incompatible with production of an immune response by an inactivated pathogen, its use in the immunogenic compositions is contemplated. Supplementary active ingredients also can be incorporated into the compositions. For example, certain pharmaceutical compositions can include the inactivated pathogen in an aqueous diluent, mixed with a suitable surfactant, such as hydroxypropylcellulose. Dispersions also can be prepared in glycerol, liquid polyethylene glycols, and mixtures thereof and in oils. In some cases (for example, when liquid formulations are deemed desirable, or when the lyophilized vaccine composition is reconstituted for multiple doses in a single receptacle), these preparations contain a preservative to prevent the growth of microorganisms.
(180) Pharmaceutically acceptable carriers, excipients and diluents are known to those of ordinary skill in the described, e.g., in Remington's Pharmaceutical Sciences, by E. W. Martin, Mack Publishing Co., Easton, Pa., 15th Edition (1975), describes compositions and formulations suitable for pharmaceutical delivery of inactivated pathogens.
(181) In general, the nature of the carrier will depend on the particular mode of administration being employed. For instance, parenteral formulations usually comprise injectable fluids that include pharmaceutically and physiologically acceptable fluids such as water, physiological saline, balanced salt solutions, aqueous dextrose, glycerol or the like as a vehicle. For solid compositions (e.g., powder, pill, tablet, or capsule forms), conventional non-toxic solid carriers can include, for example, pharmaceutical grades of mannitol, lactose, starch, or magnesium stearate. In addition to biologically neutral carriers, pharmaceutical compositions to be administered can contain minor amounts of non-toxic auxiliary substances, such as wetting or emulsifying agents, preservatives, and pH buffering agents and the like, for example, sodium acetate or sorbitan monolaurate.
(182) For example, the pharmaceutical compositions (medicaments) can include one or more of a stabilizing detergent, a micelle-forming agent, and an oil. Suitable stabilizing detergents, micelle-forming agents, and oils are detailed in U.S. Pat. Nos. 5,585,103; 5,709,860; 5,270,202, and 5,695,770. A stabilizing detergent is any detergent that allows the components of the emulsion to remain as a stable emulsion. Such detergents include polysorbate, 80 (TWEEN80) (Sorbitan-mono-9-octadecenoate-poly(oxy-1,2-ethanediyl; manufactured by ICI Americas, Wilmington, Del.), TWEEN 40™, TWEEN 20™, TWEEN 60™, Zwittergent™ 3-12, TEEPOL HB7™, and SPAN 85™. These detergents are usually provided in an amount of approximately 0.05 to 0.5%, such as at about 0.2%. A micelle forming agent is an agent which is able to stabilize the emulsion formed with the other components such that a micelle-like structure is formed. Such agents generally cause some irritation at the site of injection in order to recruit macrophages to enhance the cellular response. Examples of such agents include polymer surfactants described by, e.g., Schmolka, J. Am. Oil. Chem. Soc. 54:110, 1977, and Hunter et al., J. Immunol 129:1244, 1981, and such agents as PLURONIC™ L62LF, L101, and L64, PEG1000, and TETRONIC™ 1501, 150R1, 701, 901, 1301, and 130R1. The chemical structures of such agents are well known in the art. In one embodiment, the agent is chosen to have a hydrophile-lipophile balance (HLB) of between 0 and 2, as defined by Hunter and Bennett, J. Immun. 133:3167, 1984. The agent can be provided in an effective amount, for example between 0.5 and 10%, or in an amount between 1.25 and 5%.
(183) The oil included in the composition is chosen to promote the retention of the pathogen in oil-in-water emulsion, and preferably has a melting temperature of less than 65° C., such that emulsion is formed either at room temperature, or once the temperature of the emulsion is adjusted to room temperature. Examples of such oils include squalene, Squalane, EICOSANE™, tetratetracontane, glycerol, and peanut oil or other vegetable oils. In one specific, non-limiting example, the oil is provided in an amount between 1 and 10%, or between 2.5 and 5%. The oil should be both biodegradable and biocompatible so that the body can break down the oil over time, and so that no adverse effects are evident upon use of the oil.
(184) Optionally, the pharmaceutical compositions or medicaments can include a suitable adjuvant to increase the immune response against the pathogen. As used herein, an “adjuvant” is any potentiator or enhancer of an immune response. The term “suitable” is meant to include any substance which can be used in combination with the selected pathogen to augment the immune response, without producing adverse reactions in the vaccinated subject. Effective amounts of a specific adjuvant may be readily determined so as to optimize the potentiation effect of the adjuvant on the immune response of a vaccinated subject. For example, suitable adjuvants in the context of vaccine formulations include 0.03%-5% (e.g., 2%) aluminum hydroxide (or aluminum phosphate) and MF-59 oil emulsion (0.5% polysorbate 80 and 0.5% sorbitan trioleate. Squalene (5.0%) aqueous emulsion) is another adjuvant which has been favorably utilized in the context of vaccines. For example, the adjuvant can be a mixture of stabilizing detergents, micelle-forming agent, and oil available under the name Provax® (DEC Pharmaceuticals, San Diego, Calif.). An adjuvant can also be an immunostimulatory nucleic acid, such as a nucleic acid including a CpG motif. Other adjuvants include mineral, vegetable or fish oil with water emulsions, incomplete Freund's adjuvant, E. coli J5, dextran sulfate, iron sulfate, iron oxide, sodium alginate, Bacto-Adjuvant, certain synthetic polymers such as Carbopol (BF Goodrich Company, Cleveland, Ohio), poly-amino acids and co-polymers of amino acids, saponin, carrageenan, REGRESSIN (Vetrepharm, Athens, Ga.), AVRIDINE (N, N-dioctadecyl-N′, N′-bis(2-hydroxyethyl)-propanediamine), long chain polydispersed .beta. (1,4) linked mannan polymers interspersed with O-acetylated groups (e.g. ACEMANNAN), deproteinized highly purified cell wall extracts derived from non-pathogenic strain of Mycobacterium species (e.g., EQUIMUNE, Vetrepharm Research Inc., Athens Ga.), Mannite monooleate, paraffin oil and muramyl dipeptide. A suitable adjuvant can be selected by one of ordinary skill in the art.
(185) The pharmaceutical compositions (medicaments) can be prepared for use in therapeutic or prophylactic regimens (e.g., vaccines) and administered to human or non-human subjects to elicit an immune response against one or more pathogens. For example, the compositions described herein can be administered to a human (or non-human) subject to elicit a protective immune response against one or more pathogens. To elicit an immune response, a therapeutically effective (e.g., immunologically effective) amount of the inactivated pathogen is administered to a subject, such as a human (or non-human) subject.
(186) A “therapeutically effective amount” is a quantity of a composition used to achieve a desired effect in a subject being treated. For instance, this can be the amount necessary to stimulate an immune response, to prevent infection, to reduce symptoms, or inhibit transmission of a pathogen. When administered to a subject, a dosage will generally be used that will achieve target tissue concentrations (for example, in antigen presenting cells) that is empirically determined to achieve an in vitro effect. Such dosages can be determined without undue experimentation by those of ordinary skill in the art.
(187) An immunogenic composition, such as a vaccine composition containing an inactivated pathogen, can be administered by any means known to one of skill in the art, such as by intramuscular, subcutaneous, or intravenous injection, but even oral, nasal, and transdermal mutes are contemplated. In one embodiment, administration is by subcutaneous or intramuscular injection. To extend the time during which the inactivated pathogen is available to stimulate a response, the peptide can be provided as an oily injection, as a particulate system, or as an implant. The particulate system can be a microparticle, a microcapsule, a microsphere, a nanocapsule, or similar particle. A particulate carrier based on a synthetic polymer has been shown to act as an adjuvant to enhance the immune response, in addition to providing a controlled release.
(188) As an alternative to liquid formulations, the composition can be administered in solid form, e.g., as a powder, pellet or tablet. For example, the vaccine composition can be administered as a powder using a transdermal needleless injection device, such as the helium-powered POWDERJECT® injection device. This apparatus uses pressurized helium gas to propel a powder formulation of a vaccine composition, e.g., containing an inactivated pathogen, at high speed so that the vaccine particles perforated the stratum corneum and land in the epidermis.
(189) Polymers can be also used for controlled release. Various degradable and nondegradable polymeric matrices for use in controlled drug delivery are known in the art (Langer, Accounts Chem. Res. 26:537, 1993). For example, the block copolymer, polaxamer 407 exists as a viscous yet mobile liquid at low temperatures but forms a semisolid gel at body temperature. It has shown to be an effective vehicle for formulation and sustained delivery of recombinant interleukin-2 and urease (Johnston, et al., Pharm. Res. 9:425, 1992; and Pec, J. Parent. Sci. Tech. 44(2):58, 1990). Alternatively, hydroxyapatite has been used as a microcarrier for controlled release of proteins (Ijntema, et al., Int. J. Pharm. 112:215, 1994). In yet another aspect, liposomes are used for controlled release as well as drug targeting of the lipid-capsulated drug (Betageri, et al., Liposome Drug Delivery Systems, Technomic Publishing Co., Inc., Lancaster, Pa., 1993). Numerous additional systems for controlled delivery of therapeutic proteins are known (e.g., U.S. Pat. Nos. 5,055,303; 5,188,837; 4,235,871; U.S. Patent No. 4; 501,728; U.S. Pat. Nos. 4,837,028; 4,957,735; and 5,019,369; 5,055,303; 5,514,670; 5,413,797; 5,268,164; 5,004,697; 4,902,505; 5,506,206; 5,271,961; 5,254,342; and 5,534,496).
(190) In specific, non-limiting examples, the inactivated pathogen (e.g., a parasite, such as a protozoan parasite, or a bacterial pathogen) is administered to elicit a cellular immune response (e.g., a cytotoxic T lymphocyte (CTL) response). A number of means for inducing cellular responses, both in vitro and in vivo, are known. Lipids have been identified as agents capable of assisting in priming CTL responses in vivo against various antigens. For example, as described in U.S. Pat. No. 5,662,907, palmitic acid residues can be attached to the alpha and epsilon amino groups of a lysine residue and then linked (e.g., via one or more linking residues, such as glycine, glycine-glycine, serine, serine-serine, or the like) to an immunogenic peptide or protein. The lipidated peptide can then be injected directly in a micellar form, incorporated in a liposome, or emulsified in an adjuvant. As another example, E coli lipoproteins, such as tripalmitoyl-S-glycerylcysteinlyseryl-serine can be used to prime tumor specific CTL when covalently attached to an appropriate peptide (see, Deres et al., Nature 342:561, 1989). Further, as the induction of neutralizing antibodies can also be primed with the same molecule conjugated to a peptide which displays an appropriate epitope, two compositions can be combined to elicit both humoral and cell-mediated responses where that is deemed desirable.
(191) Dosages of inactivated pathogen are administered that are sufficient to elicit an immune response, e.g., a protective immune response, in a subject. With respect to viral pathogens, the dosage is typically calculated based on the amount of biological matter equivalent to a specified titer of infectious (e.g., virulent or attenuated) virus. For example, a dose equivalent to about 10.sup.6, or about 10.sup.7, or about 10.sup.8, or about 10.sup.9, or about 10.sup.10, or about 10.sup.11 or about 10.sup.12, or even more live virus per dose can be administered to elicit an immune response in a subject. In some cases, the dose includes an amount in excess of the amount of a live virus utilized to elicit an immune response, because the inactivated vaccine is incapable of increasing in number after administration into the subject. When calculating the amount of a cellular pathogen, e.g., a bacteria, a fungus or a parasite, the amount can be calculated by comparison to a dose of live bacteria, e.g., from about 10.sup.3 cells or organisms to about 10.sup.10 live organisms, depending on the formulation. For example, the dose can include at least about 100 nanograms (or 200 nanograms, or 500 nanograms, or 1 microgram) of protein antigen per dose to about 25 mg (e.g., about 10 mg, or about 15 mg, or about 20 mg), or even more of an inactivated pathogen. Typically the vaccine composition includes additional pharmaceutically acceptable constituents or components. Accordingly, the vaccine composition can include at least about 0.1% wt/wt inactivated pathogen to about 99% wt/wt inactivated pathogen, with the balance of the vaccine composition is made up of pharmaceutically acceptable constituents, such as a one or more pharmaceutically acceptable carrier, pharmaceutically acceptable stabilizer and/or pharmaceutically acceptable diluent. Guidelines regarding vaccine formulation can be found, e.g., in U.S. Pat. Nos. 6,890,542, and 6,651,655. Doses can be calculated based on protein concentration (or infectious units, such as HU, of infectious unit equivalents). The optimal dosage can be determined empirically, for example, in preclinical studies in mice and non-human primates, followed by testing in humans in a Phase I clinical trial. Actual methods for preparing administrable compositions will be known or apparent to those skilled in the art and are described in more detail in such publications as Remington's Pharmaceutical Sciences, 19th Ed., Mack Publishing Company, Easton, Pa., 1995.
(192) Typically, but not always, the vaccine compositions are administered prior to exposure of a subject to a pathogen, e.g., as a vaccine. Vaccine compositions can be prepared by inactivating a wide range of pathogens using dual oxidizing conditions, or using dual oxidizing conditions further comprising a methisazone reagent(s), according to the methods described herein. For example, vaccine compositions can be prepared by inactivating a pathogenic virus with a solution containing dual oxidizing reagent(s), or with a solution containing dual oxidizing reagent(s) further comprising a methisazone reagent(s). Non-limiting examples of viruses that can be inactivated by the dual oxidation methods for vaccine production are disclosed herein.
(193) Bacterial pathogens can also be inactivated using dual oxidizing reagent(s), or using dual oxidizing conditions further comprising a methisazone reagent(s), for use in vaccine compositions. Non-limiting examples of bacteria that can be inactivated by the dual oxidation methods for vaccine production are disclosed herein.
(194) Vaccine compositions can also be produced from fungal pathogens inactivated using dual oxidizing reagent(s), or using dual oxidizing conditions further comprising a methisazone reagent(s). Non-limiting examples of fungal pathogens that can be inactivated by the dual oxidation methods for vaccine production are disclosed herein.
(195) Vaccine compositions can also be produced from parasitic pathogens inactivated using dual oxidizing reagent(s), or using dual oxidizing conditions further comprising a methisazone reagent(s). Non-limiting examples of parasitic pathogens that can be inactivated by the dual oxidation methods for vaccine production are disclosed herein.
(196) It will be apparent that the precise details of the methods or compositions described can be varied or modified without departing from the spirit of the described invention. The following examples are provided to illustrate certain particular features and/or embodiments. These examples should not be construed to limit the invention to the particular features or embodiments described. Each of the references cited below is incorporated by reference for all purposes.
EXAMPLE 1
Standard H.SUB.2.O.SUB.2.-Based Inactivation was Shown to Inactivate CHIKV, but Also Damaged CHIKV-Specific Neutralizing Epitopes and Failed to Induce Neutralizing Responses In Vivo Following Vaccination
(197)
(198) In
(199)
EXAMPLE 2
Dual Oxidation-Based Microbial Inactivation was Found by Applicants to have a Fundamentally Different Mechanism Compared with Simple Oxidation with H.SUB.2.O.SUB.2 .Alone, Thereby Discouraging the Potential Use of Dual Oxidation-Based Microbial Inactivation for the Development of Advanced Efficacious Vaccine Antigens
(200) While Fenton-type reactions have only been used for killing pathogens, and have not been used or suggested for using in the development of vaccines, such reactions were nonetheless tested for the potential to inactivate microbial pathogens for purpose of vaccine production. The initial inactivation data was surprising and unexpected, because in contrast to H.sub.2O.sub.2, it was found that the total protein concentration of the solution during the inactivation procedure impacts H.sub.2O.sub.2/CuCl.sub.2 dual-oxidation inactivation kinetics. This H.sub.2O.sub.2/CuCl.sub.2 system result was unexpected because protein concentration had been previously shown to have no impact on viral inactivation using Applicants' standard H.sub.2O.sub.2 approach. However, as shown in
(201) Specifically,
(202) The dependence on total protein concentration of the solution during the dual inactivation procedure was unexpected, indicating that a fundamentally different mechanism was involved compared to H.sub.2O.sub.2 alone, and thus the efficacy/use of a dual oxidation-based inactivation procedure for effective vaccine production was questionable and unpredictable in view of Applicants' prior simple oxidation based methods (e.g., with H.sub.2O.sub.2 alone) (e.g., U.S. Pat. Nos. 8,124,397 and 8,716,000).
EXAMPLE 3
A Dual Oxidizing Fenton-Type Oxidation System was Used to Provide Efficient Inactivation while Improving the Maintenance of CHIKV-Specific Neutralizing Epitopes
(203)
(204) In
(205) In
(206) In
(207) Following treatments, antigen was tested with a CHIKV-specific sandwich ELISA comprised of two neutralizing monoclonal antibodies specific for the E1 and E2 structural proteins. ELISA values are expressed as a percentage alive virus controls. Following treatment, material was also tested for live virus using a standard plaque forming unit (PFU) assay. Resulting virus titers (PFU/mL) are indicated for each condition. Increasing concentrations of either decontamination reagent (
EXAMPLE 4
CuCl.SUB.2./H.SUB.2.O.SUB.2.—CHIKV Vaccination Induced Rapid Neutralizing Antibody Responses, and Protected Against CHIKV-Associated Pathology
(208) To assess the immunogenicity of the H.sub.2O.sub.2/CuCl.sub.2-treated CHIKV candidate, vaccine antigen was formulated with alum adjuvant and used to immunize mice at several dose levels (10 or 40 μg per animal). As shown in
(209)
(210)
(211) CuCl.sub.2/H.sub.2O.sub.2—CHIKV vaccination generated rapid and robust neutralizing antibody titers (
EXAMPLE 5
H.SUB.2.O.SUB.2./CuCl.SUB.2.-Based Oxidation was Used to Develop an Effective Inactivated YFV Vaccine
(212) Based on the encouraging results demonstrated with CHIKV, a model alphavirus, the utility of the system for flaviviruses such as YFV was explored. Preliminary analysis suggested that a concentration of 0.002% H.sub.2O.sub.2 and 1 μM CuCl.sub.2 represented a functional balance between antigenicity and rapid virus inactivation (
(213) Using a further optimized condition of 0.010% H.sub.2O.sub.2 and 1 μM CuCl.sub.2 (to ensure full inactivation) vaccine material was produced for YFV and used to immunize adult BALB/c mice. Following vaccination, all animals demonstrated measurable neutralizing titers with an average neutralizing titer of 240, compared to a neutralizing titer of less than 40 for animals immunized with YFV vaccine prepared using H.sub.2O.sub.2 alone (
(214)
(215) Specifically, as shown in
(216) Specifically, as shown in
(217) H.sub.2O.sub.2/CuCl.sub.2-based oxidation, therefore, was successfully used in the development of an inactivated YFV vaccine, and demonstrating enhanced retention of antibody binding to neutralizing epitopes (antigenicity) and improved immunogenicity after vaccination.
EXAMPLE 6
H.SUB.2.O.SUB.2./CuCl.SUB.2.-Based Oxidation was Successfully Used in the Development of an Inactivated DENV Vaccine
(218) Based on the encouraging results demonstrated with YFV, another model flavivirus, dengue 3 (DENV3) was tested in the H.sub.2O.sub.2/CuCl.sub.2 system.
(219) As with YFV, initial tests indicated that a concentration of 0.002% H.sub.2O.sub.2 and 1 μM CuCl.sub.2 represented an optimal approach for maintaining high antigenicity while also providing complete virus inactivation (
(220) Specifically,
(221) Using these preliminary H.sub.2O.sub.2/CuCl.sub.2 inactivation conditions, vaccine lots of each DENV serotype were produced, formulated into a tetravalent dengue vaccine adjuvanted with 0.10% aluminum hydroxide, and used to immunize adult rhesus macaques. Following a single booster immunization, all monkeys seroconverted (NT.sub.50≥10), with the H.sub.2O.sub.2/CuCl.sub.2 inactivation approach demonstrating an improvement in neutralizing antibody responses for 3 out of 4 dengue virus serotypes and an average 8-fold increase in geometric mean titers when compared to inactivation with H.sub.2O.sub.2 alone (
(222) Specifically,
(223) There was a small difference in antigen dose (1 μg/serotype vs. 2 μg/serotype) in these studies and so the experiment was repeated in mice that were vaccinated with the same dose of tetravalent dengue vaccine antigen (
(224) Specifically,
(225) In these experiments, the dual oxidation approach of H.sub.2O.sub.2/CuCl.sub.2 inactivation was more immunogenic than 3% H.sub.2O.sub.2 for all 4 dengue virus serotypes and resulted in an 8-fold to >800-fold improvement in neutralizing antibody titers.
EXAMPLE 7
CuCl.SUB.2./H.SUB.2.O.SUB.2.-Based Oxidation Demonstrated Improved Antigenicity with Influenza Virus
(226) Given the positive results observed across two virus families (Togaviridae and Flaviviridae), an additional virus family was chosen to test using this new inactivation platform.
(227) As shown in this working example, inactivation of Influenza A virus (family Orthomyxoviridae) was tested using a standard 3% H.sub.2O.sub.2 approach, ultraviolet inactivation, or the optimized CuCl.sub.2/H.sub.2O.sub.2 system (0.002% H.sub.2O.sub.2 and 1 μM CuCl.sub.2). To assess antigenicity, a hemagglutination activity (HA) titration assay was used. Influenza viruses naturally agglutinate red blood cells, and maintenance of this activity throughout inactivation is considered key to the immunogenicity of the final vaccine product. As shown in
(228) Specifically,
(229) By comparison, UV inactivation reduced HA activity to a negligible level. The in vivo consequence of this HA destruction can be seen in
(230) Specifically,
(231)
(232)
(233) Mice vaccinated with CuCl.sub.2/H.sub.2O.sub.2-inactivated virus or H.sub.2O.sub.2-inactivated virus showed highly significant protection following influenzae challenge (P=0.0031 and P=0.015, respectively). Whereas mice vaccinated with UV inactivated vials demonstrated no significant protection (P=0.25).
EXAMPLE 8
Multiple Transition Metals were Successfully Used in the Dual-Oxidation Approach to Vaccine Antigen Development
(234) Cu.sup.2+ (in the form of CuCl.sub.2) was the initial metal tested in the dual-oxidation vaccine antigen development studies described for CHIKV, DENV, YFV and influenza virus. However, as described above, Applicants determined that other metals also have the potential to function in a similar manner.
(235) As shown in this example using DENV3 as a model virus, inactivation studies consisting of CuCl.sub.2 (Cu.sup.2+), FeCl.sub.3 (Fe.sup.3+) or CsCl (Cs.sup.+) and dilutions of H.sub.2O.sub.2 were tested for their potential in the development of vaccine antigen.
(236) As shown in
(237) Specifically,
(238) All three metals provided conditions that maintained high levels of antigenicity while demonstrating complete virus inactivation.
EXAMPLE 9
Combinations of Transition Metals Demonstrated Synergy in the Dual-Oxidation Vaccine System
(239) As shown above in
(240) As shown in this working example, to investigate potential synergistic effects, DENV3 model virus was inactivated with combinations of CuCl.sub.2 (Cu.sup.2+) and FeCl.sub.3 (Fe.sup.3+) at a set amount of H.sub.2O.sub.2 (0.01%). A number of CuCl.sub.2/FeCl.sub.3 conditions provided full inactivation while maintaining good antigenicity, demonstrating that using multiple metals in the same inactivation condition is feasible (
(241) Specifically,
EXAMPLE 10
Dual Oxidation was Used to Provide Optimized Inactivation of Campylobacter for Improved Maintenance of Bacterial Morphology
(242) As shown in this working example, Campylobacter are small corkscrew-shaped bacteria that are typically ˜0.2 μm in diameter and ˜2-8 μm in length (
(243) Following inactivation with a standard 3% H.sub.2O.sub.2 solution for 5 hours at room temperature, the bacteria were substantially damaged with clear changes in morphology, including loss of gross cellular structure and substantial clumping (
(244) Specifically,
(245) In
(246) In
(247) In
(248) In addition to retained structure, a critical parameter for preparing an inactivated whole-cell vaccine is to ensure complete microbe inactivation. Using the optimal conditions described above, inactivation kinetic studies were performed. As shown in
(249) Specifically,
EXAMPLE 11
Dual Oxidation-Campylobacter Vaccination Provides Protective Immunity in Rhesus Macaques
(250) As shown in this working example, Applicants determined vaccine efficacy through the monitoring of Campylobacter culture-confirmed enteric disease rates in 60 CuCl.sub.2/H.sub.2O.sub.2-C. coli-immunized rhesus macaques as compared to unvaccinated control animals.
(251) For this study, animals were vaccinated intramuscularly with the CuCl.sub.2/H.sub.2O.sub.2-C. coli vaccine candidate (inactivated using 0.01% H.sub.2O.sub.2 and 2 μM CuCl.sub.2), with a booster dose administered 6-months later. Vaccinated groups were selected based on prior disease history, with preference given to groups that had historically high incidence rates of Campylobacter infection. This approach provided increased robustness in evaluating protective efficacy. All adults/juveniles (n=59) received a 40-μg alum-adjuvanted dose, with 2 small infants (<2 Kg body weight) receiving a half-dose (20-μg). According to protocol, any animal diagnosed with Campylobacter-associated diarrhea during the first 14 days after vaccination would be excluded since vaccine-mediated protection would be unlikely to occur during this early period. One adult animal was excluded from the study due to Campylobacter-associated diarrhea on the day after vaccination. Serum samples were collected from all remaining vaccinated animals (n=59) at day 0 and at 6 months after primary vaccination at which time the animals received a booster dose of vaccine.
(252) Following primary vaccination, we observed a significant increase in Campylobacter-specific serum antibody titers (
(253) Specifically,
(254) In
(255) Subsequent to vaccination, animals were followed for 8 months for C. coli-associated diarrhea, and compared (
(256) Interim analysis at 6 months after primary vaccination demonstrated no cases of C. coli or C. jejuni-associated diarrhea in the vaccinated group versus 76 cases of Campylobacter-associated diarrhea among the unvaccinated animals, representing a statistically significant protective effect against Campylobacter culture-positive diarrheal disease (P=0.035) after a single vaccination.
(257) Since nearly all human vaccines require at least two doses for optimal protective efficacy and the durability of immunological memory is often improved following booster vaccination, a conservative approach was followed by administering a booster vaccination at the 6 month time point followed by continued monitoring of the incidence of diarrheal disease among the NHP. At 250 days after primary vaccination, more cases of Campylobacter-associated enteric disease had continued to accrue among the unvaccinated population (reaching 8.7% or a total of 92 animals) whereas none of the animals (0/59) in the vaccinated cohort showed signs of disease and the statistical significance between the two groups increased to P=0.020.
EXAMPLE 12
Methisazone Enhanced the Rate of Both Single and Dual Oxidation-Based Virus Inactivation
(258) As shown in this working example, Applicants determined that methisazone enhanced the rate of both single and dual oxidation-based virus inactivation. As shown in
(259) Further, while methisazone alone had a minimal impact on virus inactivation (
(260) Specifically,
EXAMPLE 13
Methisazone Enhanced the Rate of Dual Oxidation-Based Bacterial Inactivation
(261) As shown in this working example, Applicants determined that methisazone enhanced the rate of dual oxidation-based bacterial inactivation.
(262) The results of working Example 12 were extended to bacteria (
(263) Specifically,
EXAMPLE 14
Methisazone Enhanced Inactivation Rates While Maintaining Antigenicity During Dual Oxidation-Based Viral Inactivation
(264) As shown in this working example, Applicants determined that methisazone enhanced inactivation rates while maintaining antigenicity during dual oxidation-based virus inactivation. To assess the impact of methisazone on antigenicity during inactivation, the exemplary model viruses CHIKV and DENV4 were treated with multiple inactivation approaches: high concentration H.sub.2O.sub.2 (single oxidation system), dual-oxidation (as described herein), or dual-oxidation with methisazone. As shown by the ELISA data in
(265) Specifically,
EXAMPLE 15
Chemical Analogs of Methisazone, or Methisazone Functional Groups/Substructures or Combinations Thereof; Enhanced Inactivation and Maintenance of Antigenicity During Dual Oxidation-Based Viral Inactivation
(266) As shown in this working example, Applicants determined that chemical analogs of methisazone, or methisazone functional groups/substructures or combinations thereof, enhanced inactivation and maintenance of antigenicity during dual oxidation-based viral inactivation.
(267) As mentioned above, methisazone is a compound originally developed as an in vivo antiviral agent. We tested several related compounds to determine if they provided similar enhancements to pathogen inactivation for vaccine development (
(268) Specifically,
EXAMPLE 16
Increasing Levels of Methisazone Relative to the Transition Metal Component of the Dual Oxidation System Improved the Antigenicity and Inactivation Profile of the Dual Oxidation System
(269) As shown in this working example, Applicants determined that increasing levels of methisazone relative to the transition metal component of the dual oxidation system improved the antigenicity and inactivation profile of the dual oxidation system.
(270) We examined the impact of relative concentrations of methisazone and the transition metal in the dual-oxidation system (
(271) Specifically,
(272) References supporting the working examples and incorporated by reference herein for their respective teachings:
(273) Sagripanti, J. L., L. B. Routson, and C. D. Lytle, Virus inactivation by copper or iron ions alone and in the presence of peroxide. Appl Environ Microbiol, 1993. 59(12): p. 4374-6.
(274) Nieto-Juarez, J. I., et al., Inactivation of MS2 coliphage in Fenton and Fenton-like systems: role of transition metals, hydrogen peroxide and sunlight. Environ Sci Technol, 2010. 44(9): p. 3351-6.
(275) Barbusiński, K., Fenton Reaction—Controversy concerning the chemistry. Ecological Chemistry and Engineering, 2009. 16(3): p. 347-358.
(276) Sagripanti, J. L., Metal-based Formulations with high microbicidal activity. Appl Environ Microbiol, 1992, 58(9): p. 3157-62.
(277) McClatchey, K. D., Clinical laboratory medicine. 2nd ed. 2002, Philadelphia: Lippincott Wiliams & Wilkins. xiv, 1693 p.
(278) Lippincott Williams & Wilkins., Nursing. Deciphering diagnostic tests. Nursing. 2008, Philadelphia, Pa.: Wolters Kluwer/Lippincott Williams & Wilkins. vii, 664 p.
(279) Sagripanti, J. L., et al., Mechanism of copper-mediated inactivation of herpes simplex virus. Antimicrob Agents Chemother, 1997. 41(4): p. 812-7.
(280) Sagripanti, J. L., Goering, and A. Lamanna, Interaction of copper with DNA and antagonism by other metals. Toxicol Appl Pharmacol, 1991. 110(3): p. 477-85.
(281) Toyokuni, S. and J. L. Sagripanti, Association between 8-hydroxy-2′-deoxyguanosine formation and DNA strand breaks mediated by copper and iron, in Free Radic Biol Med. 1996: United States. p. 859-64.
(282) Nguyen, T. T., et al., Microbial inactivation by cupric ion in combination with H2O2: role of reactive oxidants. Environ Sci Technol, 2013. 47(23): p. 13661-7.
(283) Thompson R L, Minton S A, Jr., Officer J E, Hitchings G H. Effect of heterocyclic and other thiosemicarbazones on vaccinia infection in the mouse. J Immunol. 1953; 70:229-34.
(284) Bauer D J. The antiviral and synergic actions of isatin thiosemicarbazone and certain phenoxypyrimidines in vaccinia infection in mice. Br J Exp Pathol. 1955; 36:105-14.
(285) Bauer D J. Clinical experience with the antiviral drug marboran (1-methylisatin 3-thiosemicarbazone). Ann N Y Acad Sci, 1965; 130:110-7.
(286) Bauer D J, Stvincent L, Kempe C H, Downie A W. Prophylactic Treatment of Small Pox Contacts with N-Methylisatin Beta-Thiosemicarbazone (Compound 33t57, Marboran). Lancet, 1963; 2:494-6.
(287) Fox M P, Bopp L H, Pfau C J. Contact inactivation of RNA and DNA viruses by N-methyl isatin beta-thiosemicarbazone and CuSO4. Ann N Y Acad Sci. 1977; 284:533-43.
(288) Logan J C, Fox M P, Morgan J H, Makohon A M, Pfau C J. Arenavirus inactivation on contact with N-substituted isatin beta-thiosemicarbazones and certain cations. J Gen Virol. 1975; 28:271-83.
(289) Mikelens P E, Woodson B A, Levinson W E. Association of nucleic acids with complexes of N-methyl isatin-beta-thiosemicarbazone and copper. Biochem Pharmacol. 1976; 25:821-7.
(290) Rohde W, Shafer R, Idriss J. Levinson W. Binding of N-methyl isatin beta-thiosemicarbazone-copper complexes to proteins and nucleic acids. J Inorg Biochem. 1979; 10:183-94.
(291) Pakravan P, Masoudian S. Study on the Interaction between Isatin-beta-Thiosemicarbazone and Calf Thymus DNA by Spectroscopic Techniques. Iran J Pharm Res. 2015; 14:111-23.