Methods for Extracting Proteins from a Blood-Based Material

Abstract

Methods of producing multiple protein products from blood-based materials including alpha-1-proteinase inhibitor, gamma globulin, albumin, and other proteins are described herein. The inventive methods include steps of fractionation that utilize a combination of salt and organic solvent. Advantageously, the inventive methods are simple and produce alpha-1-proteinase inhibitor, gamma globulin, albumin, and other proteins in high yields. The sequence of process steps can be selected to obtain multiple products from various in-process materials, such as supernatants, pastes, chromatography flow-though, and chromatography washes.

Claims

1. A method of treating an aqueous solution comprising a plurality of proteins, wherein the plurality of proteins comprises a protein of interest, comprising contacting the plurality of proteins with a salt and an organic solvent, thereby inducing formation of a supernatant and a precipitate from the aqueous solution comprising the plurality of proteins, wherein the protein of interest is included in one of the supernatant and the precipitate.

2. The method of claim 1, wherein the supernatant comprises the protein of interest.

3. The method of claim 2, comprising isolating the protein of interest from the supernatant by ion exchange chromatography.

4. The method of claim 1, wherein the precipitate comprises the protein of interest.

5. The method of claim 4, comprising isolating the protein of interest from the precipitate by ion exchange chromatography.

6. The method of claim 1, wherein the protein of interest is immunoglobulin G.

7. The method of claim 1, wherein the salt is a salt of an organic acid.

8. The method of claim 1, wherein the organic solvent is an alcohol.

9. The method of claim 8, wherein the alcohol is ethanol.

10. The method of claim 1, wherein the aqueous solution comprising the plurality of proteins comprises the salt, and wherein contacting comprises adding the organic solvent to the aqueous solution comprising a plurality of proteins.

11. The method of claim 1, wherein the aqueous solution comprising the plurality of proteins comprises the organic solvent, and wherein contacting comprises adding the salt to the aqueous solution comprising the plurality of proteins.

12. The method of claim 1, wherein contacting comprises adding both the salt and the organic solvent to the aqueous solution comprising the plurality of proteins.

13. The method of claim 12, wherein the organic solvent and the salt are provided as a mixture.

14. The method of claim 1, wherein the aqueous solution comprising the plurality of proteins is a product of a previous precipitation step.

15. The method of claim 14, wherein the previous precipitation step comprises a salt precipitation step.

16. The method of claim 14, wherein the previous precipitation step comprises an organic solvent precipitation step.

17. The method of claim 14, wherein the product of the previous precipitation step is a supernatant of the previous precipitation step.

18. The method of claim 14, wherein the product of the previous precipitation step is a precipitate of the previous precipitation step that has been re-dissolved.

19. A method of treating an aqueous solution comprising a plurality of proteins, wherein the plurality of proteins comprises a protein of interest, comprising contacting the plurality of proteins with a precipitant and an organic solvent, thereby inducing formation of a supernatant and a precipitate from the aqueous solution comprising the plurality of proteins, wherein the protein of interest is included in one of the supernatant and the precipitate.

20. The method of claim 19, wherein the supernatant comprises the protein of interest.

21. The method of claim 19, wherein the precipitate comprises the protein of interest.

22. The method of claim 19, wherein the precipitant is a salt.

23. The method of claim 19, wherein the precipitant is a hydrophilic polymer.

24. The method of claim 19, wherein the organic solvent is miscible in water and selected from the group consisting of an alcohol, a ketone, an ether, and dimethyl sulfoxide.

25. The method of claim 19, wherein the aqueous solution comprising the plurality of proteins is a product of a previous precipitation step.

26. The method of claim 25, wherein the previous precipitation step comprises addition of the precipitant.

27. The method of claim 25, wherein the previous precipitation step comprises addition of an organic solvent.

28. The method of claim 25, wherein the product of the previous precipitation step is a precipitate of the previous precipitation step that has been re-dissolved.

Description

BRIEF DESCRIPTION OF THE DRAWING

[0030] FIG. 1 is a schematic of a method of producing a protein product from a plasma-containing blood product.

[0031] FIG. 2 is a schematic of another method of producing a protein product from a plasma-containing blood product.

[0032] FIG. 3 is a schematic of another method of producing a protein product from a blood-based material.

[0033] FIG. 4 is a schematic of a method of producing multiple protein products from a single lot of blood-based material.

[0034] FIG. 5 is a schematic of a method of producing Immunoglobulin G and other protein products from a single lot of blood-based material.

[0035] FIG. 6 is a schematic of another method of producing a protein product from a blood-based material.

[0036] FIG. 7 is a schematic of another method of producing a protein product from a blood-based material.

[0037] FIG. 8 is a schematic of another method of producing a protein product from a blood-based material.

[0038] FIG. 9 is a schematic of another method of producing a protein product from a blood-based material.

[0039] FIG. 10 is a schematic of exemplary processes modules for producing protein products.

[0040] FIG. 11 is a schematic of three exemplary modular processes for producing protein products.

DETAILED DESCRIPTION

[0041] The inventive subject matter provides improved methods of producing multiple protein products in high yields from a blood plasma containing product. Blood plasma contains numerous proteins and clotting factors that are useful therapeutics. For example, alpha-1-proteinase inhibitor is used to treat people with alpha-1-proteinase inhibitor deficiency, which can cause a breakdown in lung tissue. Another class of plasma proteins is gamma globulins, which are used to treat immune deficiencies and disorders. Albumin and other proteins (e.g., fibrinogen, prothrombin, alpha-1-acid glycoprotein, alpha-1-fetoprotein, alpha-2-macroblobulin, beta-2-microglobulin, haptoglobin, ceruloplasmin, complement component 3, complement component 4, C-reactive protein, transferrin, mannose-binding lectin, etc.) can also be isolated from plasma by methods according to the inventive subject matter.

[0042] In preferred embodiments, the blood-based material comprises Recovered Plasma or salvaged plasma, and more preferably fresh frozen plasma, and even more preferably Source Plasma. Other blood-based materials may be used, for example fractionated blood, fractionated blood-based material, fractionated plasma, caprylate-fractionated plasma, polyethylene glycol-fractionated plasma, Cohn fractions, Nitschmann and Kistler fractions, and any in-process material, or other material obtained by plasma fractionation. It should be appreciated that blood plasma containing products are typically stored and transported in a frozen state, and are thawed before further processing or purification. In the thawing process, the plasma may separate into a cryoprecipitate and “cryo-poor” plasma, the cryoprecipitate-poor plasma. As used herein “cryo-poor” plasma refers to the liquid supernatant that results from thawing frozen plasma and separating the cryoprecipitate from the plasma and does not include the cryoprecipitate. Preferably the whole plasma, i.e., both the cryo-poor plasma and the cryoprecipitate, is carried through further processing steps, although use of only the cryo-poor plasma in subsequent processing steps is not excluded. Optionally, the cryoprecipitate can be reincorporated (e.g., by mixing) in the cryo-poor plasma prior to or as part of protein product production.

[0043] In FIG. 1 a flow diagram of one embodiment of the inventive subject matter is shown. A fresh or thawed blood plasma containing product and a salt are mixed, forming the first intermediate that is typically 10.1-25 wt % added salt, more typically 10.1-11, 11-13, 13-15, and 15-20 wt % added salt, preferably, 11-13 wt %, and more preferably 12 wt % the added salt. A typical tolerance for salt concentrations is ±1 wt %. Suitable salts for use in the inventive methods include, but are not limited to citrates, acetates, gluconates, and caprylates. Although solid salt can be added to the blood plasma product, in preferred methods concentrated, pH-adjusted salt solutions are added to the blood plasma product. Depending on the desired protein product, the pH of the salt solutions can be adjusted from about pH 3 to pH 8 to optimize protein fractionation.

[0044] For example, a 50 wt % citric acid stock solution can be prepared by dissolving 500 g of citric acid in 600 mL of water (e.g., water for injection). The volume of the solution is then brought up to 1000 mL with additional water. A 50% sodium citrate solution can be prepared by dissolving 500 g of tri-sodium citrate in 600 mL of water. Enough citric acid solution is added to the sodium citrate solution to obtain a solution having a pH of about 7, and then enough water is added to bring the volume to 1000 mL.

[0045] The plasma, intermediates, and supernatants can be processed at temperatures between the freezing point of the solution and ambient temperature, generally between 0 and 25° C. In one embodiment, the blood plasma product is maintained at 20° C. and room temperature citric acid/citrate solution is added to the plasma until the citric acid/citrate comprises 11-13 wt %, and preferably 12% by weight of the first intermediate so obtained. The addition of the salt will cause the first intermediate to separate into a first precipitate and a first supernatant. In another embodiment, the first intermediate is stirred and cooled to between 2-8° C. generating a precipitate. The first precipitate contains high molecular weight proteins and most lipids. Preferably, the first intermediate is stirred until precipitation is complete (typically for 60 minutes or more).

[0046] The first supernatant and the first precipitate can be separated into the first supernatant and the first paste by centrifugation or filtration as described above. The first paste can then be dissolved and subjected to further processes, such as salt fractionation, chromatography processes, other conventional protein purification methods, or combinations thereof, as discussed in this document.

[0047] In an exemplary embodiment, the first supernatant is cooled to 2-8° C., and additional citric acid/citrate solution is added to the first supernatant producing the second intermediate, which comprises 15-21, 21-23, 23-25, 25-27, and 27-30 wt % citric acid/citrate, preferably 21-23 wt % citric acid/citrate, and more preferably 22 wt % citric acid/citrate. Use of salt/buffer combinations other than citric acid/citrate is also contemplated. One having ordinary skill in the art appreciates that the concentration of salt in the second intermediate is greater than the concentration of salt in the first intermediate. Preferably, the second intermediate is stirred until formation of the second precipitate is complete, for example, overnight. Immune globulins can be found in the second precipitate.

[0048] Like the first intermediate, the second intermediate can be separated into a second supernatant and a second paste by centrifugation and/or filtration. When centrifugation is used, the second paste is the pellet formed from the second precipitate, and the second supernatant can be decanted, pipetted, or otherwise removed from the pellet. When filtration is used, the second paste is the filter cake formed by the second precipitate, and the second supernatant is the filtrate.

[0049] The eluate of the ion exchange chromatography preferably comprises one or more blood plasma proteins. In some embodiments, the eluate comprises one of alpha-1-proteinase inhibitor, a gamma globulin, albumin, fibrinogen, prothrombin, alpha-1-acid glycoprotein, alpha-1-fetoprotein, alpha-2-macroblobulin, beta-2-microglobulin, haptoglobin, ceruloplasmin, complement component 3, complement component 4, C-reactive protein, transferrin, and mannose-binding lectin. In some embodiments, the eluate comprises a combination of at least two of the above proteins.

[0050] Optionally, as shown in FIG. 2, the second supernatant can be filtered to remove bacteria, fungal spores, hyphae, and other “bioburden” using bioburden reduction filters. Exemplary bioburden reduction filters include filters made under the Sartorius, Pall, and EMD Millipore brands (e.g., Sartopore 2XLG 0.8/0.2, Supra EK1P/EAV1.5/0.2, Milligard®, Polysep® II, Lifegard™, Clarigard®, Polygard®-CN, Polygard®-CR, Polygard®-CT).

[0051] Another optional step is to reduce the citrate concentration by diafiltration and/or ultrafiltration. The size of the filter can be selected to maximize flow rate (e.g., 3-6 L/h) while preventing the protein of interest from flowing through the filter with the filtrate. For example, 30 kD membranes retain alpha-1-proteinase inhibitor but allow relatively fast flow of the liquid through the membrane. Reduction in citrate concentration can be correlated with a reduction in conductivity from about 55-60 mS/cm to about 10 mS/cm, and most preferably to 5 mS/cm or less.

[0052] Inactivation of enveloped viruses and some non-enveloped viruses can be achieved by denaturing the viral envelope membrane lipids. For example, a solvent/detergent (e.g., tri-n-butyl phosphate and polysorbate 80; tri-n-butyl phosphate and Triton X-100) can be used to treat the second supernatant. Advantageously, solvent/detergent treatment may also kill bacterial and fungal contamination and wash away endotoxins. Care should be taken during addition of solvent and/or detergent to avoid production of foam or froth in the resulting mixture in order to avoid protein denaturation. In a preferred embodiment of the inventive subject matter, 13.2 g of a 23.09:76.91 mixture of tri-n-butyl phosphate and polysorbate 80 per kg of the second supernatant is added to the second supernatant.

[0053] The inventors contemplated that affinity resins could be used to isolate individual components of protein products. As examples, ProMetic BioSciences Ltd. and ProMetic BioTherapeutics produces affinity resins that specifically bind coagulating factors, plasminogen, fibrinogen, immune globulins, albumin, alpha-1-proteinase inhibitor. GE Healthcare produces a cross-linked agarose resin bearing a single-domain antibody that binds alpha-1-proteinase inhibitor. The amount of resin required depends on the amount of protein in the second supernatant and the loading capacity of the resin. Typically, after application of the second supernatant, the affinity resin is washed with a salt solution (e.g., 100 mM NaCl) that removes proteins adsorbed to the resin by non-specific electrostatic interactions. The desired protein is then eluted from the affinity column using an eluate recommended by the resin manufacturer, although use of other elution protocols is not excluded. In the case of alpha-1-proteinase inhibitor and the GE Healthcare Alpha-1 Antitryp sin Select resin, the protein product can be eluted from the affinity chromatography column using a buffered magnesium chloride solution (e.g., 2 M MgCl.sub.2 in 50 mM Tris-HCl, pH=7.40). Typical protein product yields after the affinity chromatography step range between 70-98%.

[0054] The third intermediate is typically subjected to diafiltration/ultrafiltration to reduce the salt concentration. After diafiltration/ultrafiltration, the conductivity decreases from about 120 mS/cm to less than 10 mS/cm, and preferably 5 mS/cm or less.

[0055] The inventors expect that any affinity ligand that leaches from the resin into the third intermediate can be separated from the protein product after an ion exchange chromatography step. Suitable resins are supplied by Bio-Rad, Sigma-Aldrich, and Asahi Chemical & Industrial Co. Ltd. (e.g., Asahi Q500 anion exchange resin has exhibited a dynamic binding capacity of 26.5 mg of alpha-1-proteinase inhibitor per milliliter of resin). In contemplated methods, a 500 ml column of Q500 resin is equilibrated in 50 mM Tris-HCl, pH 7.40. The third intermediate is loaded on the column and eluted with a step gradient from 0 mM to 350 mM NaCl in 50 mM Tris-HCl, pH 7.40 buffer.

[0056] The inventive methods can further comprise a step of nano-filtration, which removes small non-enveloped viruses (e.g., Adenovirus, Parvovirus, papovaviruses, Human papillomaviruses) using a 20 nm pore filter. The nano-filtered protein product can then be further processed depending on the desired formulation. Further processing steps include one or more of ultrafiltration and/or diafiltration, formulation, a sterile filtration, filling, and lyophilization.

[0057] As depicted in FIG. 2, the flow-through, wash, and second precipitate each may contain one or a combination of the blood plasma proteins referenced herein. In preferred embodiments, the sterile filtered protein product of FIG. 2 comprises a single type of blood plasma protein. As depicted in FIG. 2, the isolation of other proteins from the second precipitate and the flow-through and wash comprises salt fractionation and chromatography processes as described herein.

[0058] FIG. 3 depicts a flow diagram similar to FIG. 1. However, the starting material in FIG. 3 is blood-based material. As described in this document, blood-based material includes Source Plasma, fresh frozen plasma, Recovered Plasma, salvaged plasma, fractionated blood, fractionated blood-based material, fractionated plasma, Cohn fractions, Nitschmann and Kistler fractions, and any in-process material of fractionated material. It is contemplated by the in-process materials from other fractionation processes, such as Cohn fractions or Nitschmann and Kistler fractions, can be used as a starting material for the method of FIG. 3. Further, it is anticipated that in-process material from any of the methods of the inventive subject matter, including at least FIGS. 1-8, can be used as a starting point for the method of FIG. 3.

[0059] It should be noted that the first salt and the second salt of FIG. 3 can be any of the salts disclosed in this document. Further, it is contemplated that first and second salts can be the same. The flow diagram of FIG. 3 also comprises first and second chromatography steps. It is contemplated that first and second chromatography steps can comprise, at least partially, affinity, gel permeation, cation exchange, anion exchange, size exclusion, hydrophobic interaction, hydroxyapatite, fluorapatite, or immobilized metal ion affinity chromatography. The first and second chromatographic steps can be in either packed bed or expanded bed adsorption mode. First and second chromatography steps can also comprise the same types of chromatography. It is contemplated that some processes may require a single chromatographic step while others may require more than two steps. If is further contemplated that protein purification from the protein fractions obtained using salts as described herein may require protein purification/stabilization steps in addition to chromatography or may require protein purification/stabilization steps other than chromatography.

[0060] As described above, it should be appreciated that the eluate from second chromatography process comprises at least one of the blood plasma proteins referenced herein.

[0061] FIG. 4 depicts a flow diagram similar to FIG. 3. However, FIG. 4 includes additional processing of first and second precipitates, and first and second flow-throughs, which produces multiple products from a single lot of blood-based material. It should be appreciated that first precipitate can be dissolved and further processed by salt fractionation and/or chromatography processes as referred to in this document. As depicted, it is preferred that the product of second through sixth chromatography steps each is an isolated blood plasma protein as described herein. In some embodiments, the first through sixth chromatography steps are each different from each other. It is contemplated that first through fifth proteins are distinct blood plasma proteins from each other, though it may be that some protein batches at least partially contain the same protein.

[0062] FIG. 5 depicts a flow diagram for isolating Immunoglobulin G (“IgG”) and other proteins from a single lot of blood-based material. The preparation of first and second intermediate can be the same or similar to the methods described above for FIGS. 1-4. As in the flow diagram of FIG. 4, the second precipitate is further processed by first chromatography step to produce IgG. While it is contemplated that first chromatography step comprises affinity chromatography by way of IgG specific affinity resin, it should be appreciated that first chromatography step can comprise, either wholly or in part, other types of chromatography as known in the art. In addition, first flow through is further processed by second chromatography step in order to produce other protein products, such as blood plasma proteins described herein. It should be appreciated that subsequent chromatography and salt fractionation steps can be performed to yield desired isolated protein products and combinations.

[0063] FIG. 6 depicts a flow diagram for an alternate method of deriving desired products from blood-based material. The flow diagram of FIG. 6 begins with processing blood-based material via a first chromatography step. In some embodiments, the blood-based material is in-process material from other fractionation processes, or otherwise fractionated blood-based material. The first flow-through of FIG. 6 is then salt fractionated as described in FIGS. 1 and 3, and a second eluate produced by processing second supernatant with second chromatography step. It should be appreciated that first and second eluates comprise blood plasma proteins as described herein. In preferred embodiments, the second eluate comprises an isolated type of blood plasma protein.

[0064] FIG. 7 depicts a flow diagram similar to FIG. 3. However, FIG. 7 discloses an embodiment comprising a third chromatography step. It should be appreciated that third chromatography step can comprise any of the chromatography steps previously discussed or known to the art. In some embodiments first through third chromatography steps comprise the same type of chromatography. Additional chromatography steps after or before the third chromatography step are also contemplated. In some embodiments, the eluate of the third chromatography step comprises at least one of the blood plasma proteins described herein. In some embodiments, the eluate comprises an isolated type of blood plasma protein.

[0065] FIG. 8 depicts a flow diagram similar to FIG. 3. However, FIG. 8 comprises an additional step of adding TCEP to the second supernatant to produce third intermediate. It is contemplated that TCEP reduces the multimer formation of at least some proteins in the second supernatant. It is also contemplated that additional or alternative reducing agents may be used to minimize multimer formation of proteins throughout the steps of FIG. 8. (e.g., DTT and βME). In some embodiments, the eluate of the second chromatography step comprises at least one of the blood plasma proteins described herein. In some embodiments, the eluate comprises an isolated type of blood plasma protein.

[0066] FIG. 9 depicts another flow diagram similar to FIG. 3. In FIG. 8, an additional precipitation step is performed by adding a precipitant to the second supernatant to produce a third intermediate. The precipitant may comprise the first or second salt (e.g., citrates, acetates, and gluconates), a different salt (e.g., sodium chloride, ammonium sulfate, a caprylate salt, etc.), a polyethylene glycol, an alcohol, or another precipitant. The third intermediate can then be separated to produce a third supernatant and a third precipitate by centrifugation and/or filtration. The third supernatant and third precipitate may each be subjected to optional purification steps (e.g., chromatography, solvent/detergent treatment, bioburden filtration, and/or concentration step(s), as described above) to produce first and second proteins, respectively. It should be appreciated that multiple protein products may be purified from either or both of the third supernatant and third precipitate.

[0067] The Inventors have unexpectedly found that, to a great extent, precipitation of proteins from blood products (e.g., serum, plasma, cryo-poor plasma, etc.) can be a function of a “total percentage concentration” of precipitating agents present in the solution, where said total percentage concentration is the sum of both the percent by weight of solid precipitants (e.g., salts, hydrophilic polymers, etc.) and the percent by volume of organic solvent (i.e., liquid or liquid phase) precipitants (e.g., water-miscible organic solvents, alcohols, acetones, etc.). For example, distribution of proteins between supernatant and precipitate phases of a precipitation reaction are similar or identical when treated with 20% (w/v) of a precipitating salt (e.g. sodium citrate) and when treated with a combination of 10% (w/v) precipitating salt and 10% (v/v) precipitating organic solvent (e.g., ethanol), a combination of 15% (w/v) precipitating salt and 5% (v/v) precipitating organic solvent (e.g., ethanol), a combination of 5% (w/v) precipitating salt and 15% (v/v) precipitating organic solvent (e.g., ethanol), etc.

[0068] Accordingly, in some embodiment's proteins can be selectively precipitated and/or maintained in supernatant or precipitate phases of a precipitating reaction that incorporates treatment of a blood product or intermediate of a protein isolation process with both solid precipitant and liquid phase precipitant, either successively or in combination. For example, a blood product or intermediate of a protein isolation process can be initially treated with a solid precipitant to generate a first supernatant and a first precipitate. This first supernatant retains dissolved solid precipitant at the applied concentration, and can be further treated with an organic solvent/liquid phase precipitant to achieve a total precipitant concentration that generates a second precipitate or second supernatant that includes the protein to be isolate. Alternatively, the initial precipitation step can be performed by addition of an organic solvent, and the resulting first supernatant treated with sufficient solid precipitant to achieve a total precipitant concentration that generates a second supernatant and a second precipitate, at least one of which includes the protein to be isolated.

[0069] In some embodiments a blood product or an intermediate from a process for isolating a protein from a blood product can be treated with a mixture of solid precipitant and organic solvent precipitant, where the solid and organic solvent precipitants in combination provide a total precipitant concentration as defined above that induces precipitation and partitioning of proteins of the starting material between precipitate and supernatant phases. For example, a stock solution of a solid precipitate can be prepared at a defined concentration (e.g., 5% to 50% by weight) to which is added an organic solvent precipitant to a defined concentration (e.g., 5% to 50% by volume). Such a mixture can be applied to a blood product or an intermediate from a process for isolating a protein from a blood product to provide a total precipitant concentration sufficient to cause precipitation, thereby partitioning proteins from the starting material into supernatant and precipitate phases.

[0070] To achieve this an organic and solid precipitants can be added to a protein-containing solution simultaneously, an organic precipitant can be added to a protein-containing solution in which the solid precipitant portion has already been dissolved, or a solid precipitant can be added to a protein-containing solution into which the organic precipitant portion has already been mixed. The order of addition may be adjusted to accommodate the sensitivity of the protein to be isolated to the organic precipitant, the lipid and/or lipoprotein content of the protein solution, and/or suitability for the overall isolation process.

[0071] The Applicant has found that lipids and lipoproteins present in blood products can be undesirably retained in intermediates steps of processes for isolating proteins from such blood products, complicating downstream processing. For example, the presence of lipids and/or lipoproteins in process intermediates can result in rapid fouling of filters utilized in filtration steps (e.g., particle removal, sterilization). This can be a significant issue when such methods are performed at process scale (e.g., greater than 5 liters). Use of organic solvents can increase the solubility of such lipids and lipoproteins (thereby retaining them in supernatant fractions that are subsequently removed from the primary process stream), however use of high concentrations (e.g., greater than 1% v/v, 2% v/v, 3% v/v, 5% v/v, 7% v/v, 10% v/v, 20% v/v, or more) organic solvent can also result in irreversible denaturation of the protein that is being isolated.

[0072] Inventors have found that the application of both solid and organic precipitants provides a mechanism for applying a total precipitant concentration that results in precipitation reactions that are useful for isolating serum proteins of medical and commercial interest while both improving solubility of lipids/lipoproteins and maintaining concentrations of organic solvents that are low enough to avoid protein denaturation (e.g., less than 10%, 8%, 6%, 4%, 2%, 1%, or 0.5%).

[0073] For example, in a method for isolating immunoglobulin G from a blood product sodium citrate can be added to give a final concentration of about 11% w/v to generate a first supernatant (which includes immunoglobulin G) as well as a first precipitate. This first supernatant can then be treated with ethanol to give a final concentration of about 10% v/v ethanol to provide a total precipitant concentration of 21%, thereby generating a second supernatant and a second precipitate. In such a process the second precipitate include immunoglobulin G and the second supernatant includes solubilized lipids and/or lipoproteins that would have been present in the second precipitate if sodium citrate had been used exclusively in both precipitation steps. Maintaining ethanol concentration at about 10% v/v minimizes or eliminates unwanted denaturation of the desired protein (in this instance immunoglobulin G).

[0074] In an alternative method for isolating immunoglobulin G from a blood product sodium ethanol can be added to give a final concentration of about 10% v/v to generate a first supernatant (which includes immunoglobulin G) as well as a first precipitate. This first supernatant can then be treated with sodium citrate to give a final concentration of about 11% w/v to provide a total precipitant concentration of 21%, thereby generating a second supernatant and a second precipitate. In such a process the second precipitate include immunoglobulin G and the second supernatant includes solubilized lipids and/or lipoproteins that would have been present in the second precipitate if sodium citrate had been used exclusively in both precipitation steps.

[0075] In such methods the organic content of such mixed solid and organic precipitant mixtures can range from 0.1% v/v to up to 40% v/v, depending upon the protein being isolated and its susceptibility to denaturation by the organic content. For example, in isolation of albumin organic content in a precipitation step utilizing a mixture of organic and solid precipitants can be as high as 20% v/v, between 10% and 15% v/v or less for isolation of an immunoglobulin (e.g., immunoglobulin G), and as low as less than 10% v/v for isolation of alpha 1 antitrypsin.

[0076] The amount or organic solvent precipitant used in such methods can be adjusted based on lipid and/or lipoprotein content of the starting blood product. For example, if lipid and lipoprotein content is high and a precipitation step calls for the use of a total precipitant concentration of 22%, 12% w/v of a solid precipitant (e.g., sodium citrate) and 10% v/v of an organic solvent precipitant (e.g., ethanol) can be used. Alternatively, if lipid and/or lipoprotein content of the blood product is low 17% w/v of a solid precipitant (e.g., sodium citrate) can be used and 5% v/v of an organic solvent precipitant can be used. Lipid and/or lipoprotein content can be determined for a blood product using conventional assays, or can be estimated based on population characteristics of the donor or donor pool.

[0077] Suitable solid precipitants include, but are not limited to, inorganic salts, salts of organic acids, and hydrophilic polymers. Suitable inorganic salts include chloride, phosphate, and sulfate salts. Suitable salts of organic acids include citrate and acetate salts. Suitable hydrophilic polymers include polyethylene glycols, polyvinylpyrrolidones, and dextrans, and can have molecular weights ranging from 2 kD to 10.sup.6 kD. Such solid precipitates can be added directly to blood product or intermediate from a method for isolating a protein from a blood product as a solid, or can be dissolved to form a stock solution that is then added.

[0078] Suitable organic solvent precipitants include, but are not limited to alcohols, ketones, and ethers that are miscible in water. Suitable alcohols include methanol, ethanol, and isopropyl alcohol. Suitable ketones include C1 to C5 ketones, such as acetone. Suitable water soluble ethers include ethylmethyl ether and diethyl ether. Such organic solvent precipitates can be added directly to blood product or intermediate from a method for isolating a protein from a blood productor can be mixed with water or an aqueous solvent to form a stock solution that is then added.

Example

[0079] Human plasma was subjected to sequential 12% citrate and 22% citrate protein precipitation steps as described in U.S. Pat. No. 7,879,331. The citrate concentration of the supernatant resulting from fractionation at 22% citrate was increased in separate studies to 26%, 30% or 34%. The resulting intermediate was chilled to below 5° C. with stirring, and stirred at this temperature for 60 minutes. The precipitate was separated by centrifugation (as described in U.S. Pat. No. 7,879,331) and the fractions analyzed by nephelometry for alpha-1-proteinase inhibitor (A1PI), albumin, and total protein. The results are presented in the Table 1. The values are the percentages found in each of the supernatant (super) and the precipitate (ppt), normalized to 100% (sum of supernatant and precipitate).

TABLE-US-00001 TABLE 1 Sample A1PI Total protein Albumin 26% Cit super 99 94 98 26% Cit ppt BDL 6 2 30% Cit super 97 89 96 30% Cit ppt 3 10 4 34% Cit super 97 92 97 34% Cit ppt 3 8 3

[0080] Advantageously, increasing citrate concentration removed additional proteins from the resulting supernatant while only a small fraction of the alpha-1-proteinase inhibitor and albumin were precipitated. Therefore, performing a third precipitation step may be useful in removing non-product proteins from the resulting supernatant while losing only a small fraction of the protein product(s). In yet further aspects of the inventive subject matter, processes for producing products from blood-based materials can comprise first and second modules. Each module is configured to receive an input material and to yield at least one output material. The first and second modules can each comprise a fractionation module, a chromatography module, a filtration module, a separation module, or a sterilization module. The input of one module can comprise the output of another module.

[0081] FIG. 10 depicts several modules contemplated by the inventive subject matter. In fractionation modules, the input material is fractionated by salt fractionation, Cohn fractionation, or Nitschmann and Kistler fractions, caprylate fractions or variations thereof. Salt is added to the input material, creating an intermediate. When a module employs a salt fractionation step as discussed herein, the output material comprises at least a supernatant and a paste or precipitate.

[0082] In regard to chromatography modules, input material is separated into a flow-through a wash, and one or more eluates by chromatography processes. Suitable chromatography processes include affinity chromatography, gel permeation, cation exchange, anion exchange, hydrophobic interaction, hydroxyapatite, fluoroapatite, expanded bed absorption, or immobilized metal ion affinity chromatography. The output material of the chromatography modules comprises at least a flow-through and an eluate, and can include a wash.

[0083] Ultrafiltration and diafiltration modules are also contemplated. It should be appreciated that diafiltration or ultrafiltration modules are suitable filtration methods for desalting and concentrating input materials, respectively. Additionally, viral reduction modules (e.g., via nanofiltration or otherwise described herein) and viral inactivation modules (e.g., via solvent/detergent treatment or otherwise described herein) are also contemplated. Further, reductant/stabilization modules (e.g., via treatment with TCEP, DTT, βME, or other suitable reducing agents) are contemplated by the inventive subject matter.

[0084] The sequence of modules can be configured to produce a variety of products from blood-based material. With respect to the number of modules employed in the inventive processes, the inventors contemplate that the number of modules required depends on the number of modular process steps required to produce the desired product. Some embodiments comprise one or two modules. Preferred methods of the inventive subject matter include three, four, five, six, seven, eight, nine, ten or more modules.

[0085] FIG. 11 depicts a number of sample modular processes of the inventive subject matter that employ the modules of FIG. 10. It should be appreciated that the output from one module is used as the input of another module. As depicted in process A of FIG. 11, blood-based material is used as the input material of a fractionation module. At least one of the outputs of the fractionation module (supernatant and paste) is used as the input material for a diafiltration module. The output of the diafiltration module is then further used as input material in downstream processes.

[0086] Process B of FIG. 11 uses blood-based material as the input material in a fractionation module. At least one of the outputs of the fractionation module (supernatant and paste) is used as the input material for a diafiltration module. The output of the diafiltration module is then used as input material in chromatography module 1. At least one of the outputs of chromatography module 1 (flow-through, wash, and eluate) are used as an input material in chromatography module 2. It should be appreciated that chromatography modules 1 and 2 can be the same type of chromatography or can be different types of chromatography. At least one of the outputs of chromatography module 2 are used as an input material in a viral inactivation module. The output of the viral inactivation module is used as the input material in a viral reduction module. The output of the viral reduction module comprises a blood-based protein (e.g., at least one of alpha-1-proteinase inhibitor, gamma globulin, immunoglobulin, albumin, factor VIII, factor IX, factor XIII, protein C, antithrombin III, fibrinogen, and C1 esterase inhibitor).

[0087] Process C of FIG. 11 uses plasma as the input material in fractionation module 1. At least one of the outputs of fractionation module 1 (supernatant and paste) is used as the input material for fractionation module 2. It should be appreciated that fractionation modules 1 and 2 can be the same type of fractionation or can be different types of fractionation. At least one of the outputs of fractionation module 2 is used as the input material for a viral inactivation module. The output of the viral inactivation module is used as the input material of a diafiltration module. The output of the diafiltration module is then used as input material in chromatography module 1. At least one of the outputs of chromatography module 1 (flow-through, wash, and eluate) are used as an input material in a reductant module. The output of the reductant module is then used as the input material of chromatography module 2. It should be appreciated that chromatography modules 1 and 2 can be the same type of chromatography or can be different types of chromatography. At least one of the outputs of chromatography module 2 is used as an input material in a viral reduction module. The output of the viral reduction module comprises a blood-based protein (e.g., at least one of alpha-1-proteinase inhibitor, gamma globulin, immunoglobulin, albumin, factor VIII, factor IX, factor XIII, protein C, antithrombin III, fibrinogen, and C1 esterase inhibitor).

[0088] It is further contemplated that the input material for the first module can comprise at least one of a blood-based material and an output material from any other module, e.g., a flow-through, an eluate, a supernatant, a paste, or a dissolved paste. Recycling of output materials from one module back into the same module is not excluded.

[0089] The numbers expressing quantities of ingredients, properties such as concentration, reaction conditions, and so forth, used to describe and claim certain embodiments of the invention are to be understood as being modified in some instances by the term “about.” Accordingly, the numerical parameters set forth in the written description and attached claims are approximations that can vary depending upon the desired properties sought to be obtained by a particular embodiment. The numerical parameters should be construed in light of the number of reported significant digits and by applying ordinary rounding techniques. Notwithstanding that the numerical ranges and parameters setting forth the broad scope of some embodiments of the invention are approximations, the numerical values set forth in the specific examples are reported as precisely as practicable. The numerical values presented in some embodiments of the invention may contain certain errors necessarily resulting from the standard deviation found in their respective testing measurements.

[0090] As used in the description herein and throughout the claims that follow, the meaning of “a,” “an,” and “the” includes plural reference unless the context clearly dictates otherwise. Also, as used in the description herein, the meaning of “in” includes “in” and “on” unless the context clearly dictates otherwise.

[0091] The recitation of ranges of values herein is merely intended to serve as a shorthand method of referring individually to each separate value falling within the range. Unless otherwise indicated herein, each individual value is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g., “such as”) provided with respect to certain embodiments herein is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention otherwise claimed. No language in the specification should be construed as indicating any non-claimed element essential to the practice of the invention.

[0092] Groupings of alternative elements or embodiments of the invention disclosed herein are not to be construed as limitations. Each group member can be referred to and claimed individually or in any combination with other members of the group or other elements found herein. One or more members of a group can be included in, or deleted from, a group for reasons of convenience and/or patentability. When any such inclusion or deletion occurs, the specification is herein deemed to contain the group as modified thus fulfilling the written description of all Markush groups used in the appended claims.

[0093] It should be apparent to those skilled in the art that many more modifications besides those already described are possible without departing from the inventive concepts herein. The inventive subject matter, therefore, is not to be restricted except in the scope of the appended claims. Moreover, in interpreting both the specification and the claims, all terms should be interpreted in the broadest possible manner consistent with the context. In particular, the terms “comprises” and “comprising” should be interpreted as referring to elements, components, or steps in a non-exclusive manner, indicating that the referenced elements, components, or steps may be present, or utilized, or combined with other elements, components, or steps that are not expressly referenced. Where the specification claims refer to at least one of something selected from the group consisting of A, B, C . . . and N, the text should be interpreted as requiring only one element from the group, not A plus N, or B plus N, etc.

[0094] The discussion herein provides many example embodiments of the inventive subject matter. Although each embodiment represents a single combination of inventive elements, the inventive subject matter is considered to include all possible combinations of the disclosed elements. Thus, if one embodiment comprises elements A, B, and C, and a second embodiment comprises elements B and D, then the inventive subject matter is also considered to include other remaining combinations of A, B, C, or D, even if not explicitly disclosed.