IMMUNIZATION WITH POLYVALENT VENOM VACCINES

Abstract

This disclosure relates to materials and methods useful for vaccinating mammals against the effects of envenomation by venomous organisms (including the Western Rattlesnake) by making use of venom from multiple distinct populations, subspecies or species of the organism, to make a vaccine more broadly protective against other populations, subspecies or species.

Claims

1. A method of immunizing a mammal against envenomation by a rattlesnake comprising: administering an effective amount of a polyvalent toxoid vaccine to the mammal, wherein the polyvalent toxoid vaccine comprises a combination of denatured venoms from populations of Western Rattlesnakes selected from the Southern Sierra Nevada Mountains, Calif.; the Transverse Mountains, Calif.; and, the San Jacinto Mountains, Calif.

2. The method of claim 1 wherein the Western Rattlesnake is a Southern Pacific, Northern Pacific, Mojave, Southwestern Speckled, Western Diamondback, or Red Diamondback rattlesnake.

3. The method of claim 2 wherein the Southern Pacific species is the Southern California or San Jacinto subspecies.

4. The method of claim 1 wherein the vaccine is prepared as a solution.

5. The method of claim 4 wherein the solution has a final concentration of 1 microgram of toxoid per milliliter of solution.

6. The method of claim 1 further including one or more members selected from the group consisting of: adjuvants, stabilizers, buffers, salts, preservatives and one or more pharmaceutically acceptable carriers.

7. The method of claim 6 wherein the adjuvant is alum.

8. The method of claim 6 wherein the preservative is thimerosal.

9. The method of claim 1 wherein the venoms are denatured by heating.

10. The method of claim 1 wherein the venoms are denatured by irradiation.

11. The method of claim 1 wherein the administration is by intraperitoneal, intravenous, intramuscular or subcutaneous injection.

12. The method of claim 1 wherein the mammal is a dog.

13. The method of claim 1 wherein the polyvalent toxoid vaccine is administered at a concentration of 1 microgram of toxoid per milliliter of solution.

14. The method of claim 1 wherein the formulation is administered at least twice annually.

15. The method of claim 14 wherein the formulation is administered at least three times annually.

16. The method of claim 14 wherein the second administration is at least 30 days after the first administration.

17. The method of claim 13 wherein the dog weighs less than 25 or more than 100 pounds.

18. The method of claim 1 wherein the polyvalent toxoid vaccine consists essentially of a combination of denatured venoms from populations of Western Rattlesnakes selected from the Southern Sierra Nevada Mountains, Calif.; the Transverse Mountains, Calif.; and, the San Jacinto Mountains, Calif.

19. The method of claim 18 wherein the Western Rattlesnake is a Southern Pacific, Northern Pacific, Mojave, Southwestern Speckled, Western Diamondback, or Red Diamondback rattlesnake.

20. The method of claim 19 wherein the Southern Pacific snake is the Southern California or San Jacinto subspecies.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0024] FIG. 1 shows the results of a vaccine immunization experiment with mice, where the serum from immunized mice and a control group was reacted with the venom from the various rattlesnake species and sub-species and regions in California, as shown in the panels. The change in optical density, following reaction of the reacted serum with a secondary antibody, in vaccinated mice (represented with horizontally hatched bars) as against control mice (with diagonally hatched bars) is shown in the panels. An asterisk (*) indicates a statistical difference p<0.001.

[0025] FIG. 2 shows the results of a venom challenge experiment, where the immunized group (dotted lines in each panel) and control group (solid lines in each panel) were injected intraperitoneally with a venom dosage from a species or subspecies shown in each panel above LD50, and survivorship was monitored for 48 hours. Internal body temperature was monitored as a proxy for survivorship and used to determine a humane end point for moribund individuals.

DETAILED DESCRIPTION

[0026] The method of generating and dosing a mammal with Western Rattlesnake toxoid vaccine is illustrated further by the following additional Example 1, and examples of other toxoid vaccines follow. The examples are not to be construed as limiting the disclosure in any way to the specific procedures or products described in them, or in any way other than as stated in the claims.

[0027] The goal in dosing is to expose the subject to all antigens needed to stimulate the animal's immune system to defend against rattlesnake and/or other snake venom. A number of well-known formulations and administration protocols can be used to accomplish this, including intraperitoneal, intravenous, intramuscular, or subcutaneous injection. Any other administration method which can meet the goal stated above can also be used.

[0028] In addition to adjuvants, stabilizers, buffers and salts, the formulation can include any “pharmaceutically acceptable carrier” including, by way of non-limiting example, a pharmaceutically acceptable solvent, suspending agent, or any other pharmacologically inert vehicle for delivering toxoids to a subject. Pharmaceutically acceptable carriers can be liquid, and can be selected with the planned manner of administration in mind so as to provide for the desired bulk, consistency, and other pertinent transport and chemical properties. Examples of pharmaceutically acceptable carriers include, without limitation, water; saline solution; fillers (e.g., lactose and other sugars, gelatin, or calcium sulfate); lubricants (e.g., starch, polyethylene glycol, or sodium acetate); disintegrates (e.g., starch or sodium starch glycolate); and wetting agents (e.g., sodium lauryl sulfate).

Example 1. ELISA Protocol of Experiments Demonstrating Protection Against Several Venom Types with a Polyvalent Vaccine

[0029] Vaccine Formulation: one milliliter (mL) of vaccine contains venom from the Western Rattlesnake (Crotalus oreganus) in the quantities and where the donor snakes were from the regions indicated: [0030] 0.493 mg of venom from donors from the Southern Sierra Nevada Mountains, California; [0031] 0.493 mg of venom from donors from the Transverse Mountains, Calif.; [0032] 0.014 mg of venom from donors from the San Jacinto Mountains, Calif.; [0033] 1:4 Aluminum Hydroxide (Alhydrogel®, InvivoGen); and [0034] 0.001-0.01% Thimerosal (U.S. Pharmacopeia, 2004).

[0035] To determine whether the vaccine could elicit an immune response in a mouse model, and show broad protection, an ELISA was conducted and included, as control, a comparison of the specific immunity of vaccinated mice with those immunized using adjuvant alone. To demonstrate broad protection, specific immunity was determined for individual mice against venoms from rattlesnakes from eight regions, collectively representing six species and subspecies; that is: two populations of Northern Pacific Rattlesnake (Crotalus oreganus oreganus; captured from Napa Valley to Sacramento, Calif.; and New Cuyama to Tehachapi, Calif.); two populations of Southern Pacific Rattlesnake (Crotalus oreganus helleri; captured from Southern California from Santa Barbara south, and San Jacinto Mountain Range); Western Diamondback Rattlesnake (Crotalus atrox); Red Diamondback Rattlesnake (Crotalus ruber); Southwestern Speckled Rattlesnake (Crotalus mitchelli pyrrhus); and Mojave Rattlesnake (Crotalus scutulatus scutulatus). A group of 20 mice were immunized with the vaccine and alum as the adjuvant to generate polyclonal antibodies using a protocol substantially replicated from Cates et al. (2015), with two vaccine doses there the first dose was given on day 0 and the second on day 28. Blood serum was collected from the mice on day 56. A different secondary antibody (Santa Cruz Biotechnology, m-IgGx BP-HRP, sc-516102) was used instead of the antibody used by Cates et al., which had been discontinued by the manufacturer.

[0036] To prepare the plates, 100 micrograms of each of the eight snake venoms was incubated overnight to induce binding to the wells of an individual ELISA plate (one plate for each venom type). After washing and blocking, 50 μl of mouse serum (diluted 1:8000) was added to the wells. Control wells for the plate (containing assay reagents) and sample wells, run in triplicate, containing serum from all twenty mice (both those immunized with vaccine and adjuvant only control) were run simultaneously against a single snake venom. Then the assay process was repeated with another venom until all eight venom types had been completed. This protocol eliminated plate to plate and run to run variations.

[0037] Binding was detected using anti-mouse goat antibodies with HRP-conjugated label, developed with Thermo Scientific Ultra TMB, and the reaction was stopped with sulfuric acid. Developed plates were immediately read at 450 nm. Optical densities measured for each well were averaged and a baseline for detection determined by averaging control wells (12×) for each plate. Results are depicted in FIG. 1.

[0038] To determine whether there was a significant difference in the specific immunity of vaccinated and adjuvant-only control mice, Multiple Response Permutation Procedures (MRPP) with post hoc Indicator Species Analysis was performed. This pair of statistical tests is most similar to Multivariate Analysis of Variance (MANOVA) with post hoc tests, and is used to detect statistical differences between known groups and then determine what variables are responsible for determining this difference. MRPP is a non-parametric multivariate procedure that was originally designed for ecological data that violated assumptions of conventional (M)ANOVA, especially the requirement for normally-distributed data. MRPP produces both: (i) a test of significance (p-value) as a criteria for determining whether to reject or fail to reject the null hypothesis that all groups are equal and (ii) a measure of effect size (A-value) known as the chance-corrected within-group agreement (McCune and Grace, 2002). The A statistic describes within-group homogeneity, where A=1 would indicate that all samples are identical within groups. McCune and Mefford (2011) have indicated that A>0.3 is fairly high. Vaccinated mice had significantly higher specific immunity compared to mice inoculated with adjuvant only (MRPP: p<0.0001, A=0.48).

[0039] Indicator Species Analysis (ISA) was used as a post hoc analysis to MRPP to determine which specific immunities were responsible for driving separation between vaccinated and control mice. The procedure calculates an indicator value (IV) ranging from zero (no indication) to 100 (perfect indication).

[0040] Any particular ‘species’ (in this case an individual snake venom) with perfect indication would allow determination of whether a mouse was from the vaccinated or control group based on the level of specific immunity towards that venom. In addition to the indicator value calculation, a randomization test was conducted to produce a p value to determine whether to reject or fail to reject the null hypothesis that the indicator value is not larger than expected by chance (i.e. that a venom is not a good indicator of treatment group compared to random chance). All eight venoms tested had indicator values with p<0.001 and most with strong indication, IV>80: C. o. oreganus (Napa/Sacramento), IV=80.5; C. o. oreganus (New Cuyama/Tehachapi), IV=81.7; C. o. helleri (So. CA), IV=85.3; C. o. helleri (San Jacinto), IV=71.9; C. atrox, IV=84.5; C. ruber, IV=87.1; C. m. pyrrhus, IV=85.7; C. s. scutulatus, IV=67.5. The two venoms that produced the lowest responses, C. o. helleri (San Jacinto) and C. s. scutulatus, are venoms with an abundance of small myotoxins that may represent moieties that are more difficult for mice to develop an immune response against. However, in both cases vaccinated mice produced detectable quantities of antibodies in a statistically significantly manner; whereas control mice did not have a detectable level of antibodies that were able to bind these venoms.

Example 2: Venom Challenge Experiment

[0041] Following the same vaccination protocol as in Example 1 experiment, eighty 8-10 week old female CD-1 (Charles Rivers) mice were randomly sorted into two groups and immunized by subcutaneous injection with either 0.1 mL the vaccine (vaccinated group) or 0.1 mL of Aluminum Hydroxide (Alhydrogel®, InvivoGen) adjuvant (control group). The first vaccine dose was given on day 0 and the second on day 28. On day 56, mice were separated into five venom challenge groups and were injected intraperitoneally with venoms from prevalent rattlesnake subspecies in California. Challenge doses were set above the Lethal Dose 50% (LD50), a standard value derived for a given toxicant that describes the dose at which 50% of a population should succumb to the toxicity of the substance. Survivorship was monitored for 48 hours to determine if vaccination with the vaccine allowed mice to survive a venom challenge (i.e. increased survivorship, decreased mortality). Internal body temperature was monitored as a proxy for survivorship and used to determine a humane end point for moribund individuals. Time to death in minutes was recorded, survivorship curves were plotted, and a Kaplan-Meier Survivorship Analysis (Log Rank) was used to determine whether there were significant differences in survivorship between vaccinated and unvaccinated mice. See FIG. 2. In all groups, all control (unvaccinated) mice succumbed to the venom dose, while a significantly greater number of vaccinated mice survived (p<0.01 for all; at least 50% survivorships for all groups).

Example 3: Vaccine Preparation and Administration

[0042] A vaccine created from the venom of Western Rattlesnakes selected from three distinct regions (Southern Sierra Nevada Mountains, Calif.; Transverse Mountains, Calif.; San Jacinto Mountains, Calif.) will provide protection against dangerous components of Western Rattlesnake venom throughout its range—which includes a number of western states (CA, WA, OR, NV, AZ, UT, ID, WY, CO), and parts of British Columbia and northwestern Mexico. Liquid or lyophilized venom samples from Western Rattlesnakes from these three regions are combined in approximately equal parts, heated or irradiated to denature the dangerous components to produce a toxoid mixture, and mixed with an adjuvant, such as alum, stabilizers, buffers, salts, and one or more pharmaceutically acceptable carriers, to produce the final formulation of the polyvalent Western Rattlesnake venom vaccine. A preferred final dosage concentration is one microgram of the ingredient toxoid per one milliliter dose (i.e., a combination of venom from each of the three California regions above totaling one milligram per one milliliter dose) of denatured venom.

[0043] To immunize a less than one hundred pound canine or other mammal, one dose is injected, preferably subcutaneously, at least once annually, and preferably, at least twice with at least a 30 day interval between doses, before contact between the mammal and rattlesnakes. Ideally, the dosing schedule would be completed before annual warming following the spring equinox in many of the states that have Western Rattlesnake and/or other rattlesnake and venomous snake populations. Some species/geographically distinct populations of rattlesnakes are active year-round in parts of Mexico, California and Arizona so protection of mammals in these locations may require at least bi-annual dosing as protection may fail to extend over the entire rattlesnake active period. Further, dogs over 100 pounds or under 25 pounds may benefit from at least three annual dosings, with the first two doses administered as above and with a third dose administered 30 days after the second dose.

Example 4. Vaccination Against Viruses and Parasites

[0044] Published maps of the distribution of the various mosquito vectors in the United States can be combined with the distribution of antigens from several mosquito-borne viruses such as West Nile virus, chikungunya virus, the four common variants of dengue virus, and the Zika virus to determine which components from these viruses will provide all of the dangerous mosquito-borne parasites (like those causing malaria) and viruses likely to be encountered in the U.S. These virus or parasite samples are combined and treated to generate toxoids, and produce a formulation for administration, as in Examples 1 and 2. The formulation is administered as in Example 2.

Example 5. Vaccination Against Other Snakes and Venoms

[0045] Published maps of the distribution of a variety of snakes and scorpions native to the Asia and Africa, including the Palestine Yellow Scorpion (Leiurus quinquestriatus), fat-tailed scorpions such as the black scorpion (Androctonus crassicauda) and A. amoreuxi, as well as Buthacus arenicola, Buthus occcitanus, and the Egyptian Cobra (Naja haje), the Black Desert Cobra (Walterinnesia aegyptia), the Puff Adder (Bitis arietans), the Painted Saw-Scaled Viper (Echis coloratus), the Indian Saw-Scaled Viper (E. carinatus), and the Saharan Horned Viper (Cerastes cerastes), are utilized in combination with data on the characterization of each distinct venom component from these species to determine the minimal set of organisms which will provide complete coverage of every distinct venom component. Liquid venom samples from the identified organisms are combined, treated, formulated, and administered as in Examples 1 and 2.

[0046] Any combination of features of the above process and products are within the scope of the instant disclosure.

[0047] The components, steps, features, objects, benefits, and advantages that have been discussed are merely illustrative. None of them, nor the discussions relating to them, are intended to limit the scope of protection in any way. Numerous other embodiments are also contemplated. These include embodiments that have fewer, additional, and/or different components, steps, features, objects, benefits, and/or advantages. These also include embodiments in which the components and/or steps are arranged and/or ordered differently.

[0048] Unless otherwise stated, all measurements, values, ratings, positions, magnitudes, sizes, and other specifications that are set forth in this specification, including in the exemplary features that follow, are approximate, not exact. They are intended to have a reasonable range that is consistent with the functions to which they relate and with what is customary in the art to which they pertain.

[0049] All articles, patents, patent applications, and other publications that have been cited in this disclosure are incorporated herein by reference.

[0050] Relational terms such as “first” and “second” and the like may be used solely to distinguish one entity or action from another, without necessarily requiring or implying any actual relationship or order between them. The terms “comprises,” “comprising,” “including” and any other variation thereof when used in connection with a list of elements in the specification or claims are intended to indicate that the list is not exclusive and that other elements may be included. Similarly, an element preceded by an “a” or an “an” does not, without further constraints, preclude the existence of additional elements of the identical type.

[0051] The abstract is provided to help the reader quickly ascertain the nature of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope. In addition, various features in the foregoing detailed description are grouped together in various embodiments to streamline the disclosure.

TABLE OF REFERENCES

[0052] McCune, B., & Grace, J. (2002). Analysis of Ecological Communities. MjM Software, Gleneden Beach, Oreg., U.S.A. [0053] McCune, B. & Mefford, M. J. (2011). PC-ORD. Multivariate Analysis of Ecological Data. Version 6.0. MjM Software, Gleneden Beach, Oreg., U.S.A. [0054] Cates, C. C., Valore, E. V., Couto, M. A., Lawson, G. W., & McCabe, J. G. “Comparison of the protective effect of a commercially available western diamondback rattlesnake toxoid vaccine for dogs against envenomation of mice with western diamondback rattlesnake (Crotalus atox), northern Pacific Rattlesnake (Crotalus oreganus oreganus), and southern Pacific Rattlesnake (Crotalus oreganus helleri) venom.” American Journal of Veterinary Research, 76(3), 272-279 (2015).