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Vaccines against intracellular pathogens using antigens encapsulated within biodegradable-biocompatible microspheres |
| RE40786 |
Vaccines against intracellular pathogens using antigens encapsulated within biodegradable-biocompatible microspheres
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| Patent Drawings: | |
| Inventor: |
Burnett, et al. |
| Date Issued: |
June 23, 2009 |
| Application: |
09/586,747 |
| Filed: |
June 2, 2000 |
| Inventors: |
Burnett; Paul R. (Silver Spring, MD)
van Hamont; John E. (West Point, NY)
Reid; Robert H. (Kensington, MD)
Setterstrom; Jean A. (Alpharetta, GA)
Van Cott; Thomas C. (Brookeville, MD)
Birx; Deborah L. (Potomac, MD)
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| Assignee: |
The United States of America as represented by the Secretary of the Army (Washington, DC) |
| Primary Examiner: |
Wang; Shengjun |
| Assistant Examiner: |
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| Attorney Or Agent: |
Arwine; Elizabeth |
| U.S. Class: |
424/499; 424/422; 424/426; 424/455; 424/486; 424/488 |
| Field Of Search: |
424/499; 424/422; 424/426; 424/455; 424/486; 424/488; 424/418 |
| International Class: |
A61K 38/00; A61K 9/00; A61K 9/16; A61K 9/50; C07K 14/195; C07K 14/245 |
| U.S Patent Documents: |
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| Foreign Patent Documents: |
0052510; WO 92/22654; WO 95/11010 |
| Other References: |
Gilding, Biodegradable polymers for use in surgery-polyglycolic/poly (ac c acid) homo-and copolymers: 1, Polymer, vol. 20, Dec. 1979, pp.1459-1464. cited by other.
Biotechnology News, Aug. 22, 1997, vol. 17, No. 20, Topical DNA vaccine elicits immune response. cited by other.
Hall, et al., Purification and Analysis of Colonization Factor Antigen 1, Coli Surface Antigen 1, and Coli Surface ANtigen 3 Fimbriae from Enterotoxigenic Escherichis Coli, Journal of Bacteriology, Nov. 1989, pp. 6372-6374, vol. 171, No. 11. citedby other.
Evans, et al. Purification and Characterization of the CFR/1 Antigen of Enterotoxigenic Escherichia coli, Infection and Immunity, Aug. 1979, pp. 738-748, vol. 25. cited by other.
Karjalainen, et al., Molecular Cloning and Nucleotide Sequence of the Colonization Factor Antigen I Gene of Escherichia coli, Infection and Immunity, Apr. 1989, pp. 1126-1130, vol. 57. cited by other.
Jeyanthi, et al., Novel, Burst Free Programmable Biodegradable Microspheres For Controlled Release of Polypeptides, Proceedings Int. Symp. control Release Bioact. Mater. (1996) pp. 351-362/. cited by other.
Yeh, A novel emulsification-solvent extraction technique for production of protein loaded biodegradable microparticles for vaccine and drug delivery, Journal of Controlled Release 33 (1995) 437-445. cited by other.
Yan, Characterization and morphological analysis of protein-loaded poly(lactide-co-glycolide) microparticles prepared by watewr-in-oil-in-water emulsion technique, Journal of Controlled Release, 32 (1994) 231-241. cited by other.
Wang, et al., Influence of formulation methods on the in vitro controlled release of protein from poly (ester) microspheres Journal of Controlled Release, 17 (1991) 23-32. cited by other.
Brown, Wonder Drugs' Losing Healing Aura, The Washing Post, Jun. 26, 1995, A section. cited by other.
Setterstrom, Controlled Release of Antibiotics From biodegradable Microcapsules For Wound Infection Control, Chemical Abstracts, 1983, pp. 215-226. cited by other.
Perez-Casal, et al., Gene Encoding the Major Subunit of CS1 Pili of Human Enterotoxigenic Escherichia Coli, Infection and Immunity, Nov., 1990, pp. 3594-3600, vol. 58, No. 11. cited by other.
Jordi, et al., Analysis of the first two genes of the CSI fimbrial operon in human enterotoxigenic Escherichia coli of serotype 0139: H28, FEMS Microbiology Letters 80, (1991) pp. 265-270. cited by other.
Tan, et al., Mapping the Antigenic Epitopes of Human Dihydrofolate Reductase by Systematic Synthesis of Peptides on solid Supports, The Journal of Biological Chemistry, vol. 265, No. 14, Issue of May 15, pp. 8022-8026 (1990). cited by other.
McConnel, et al., Antigenic homology within human enterotoxigenic Esherichia coli fimbrial colonization factor antigens: CFA/I, coli-surface-associated antigens (CS)1, CS2, CS4 and CS17, FEMS Microbiology Letters 61 (1989) 105-108. cited by other.
Van der Zee, Efficient mapping and characterization of a T cell epitope by the simultaneous synthesis of multiple peptides, Eur. J. Immunol. 1989, 19: 43-47. cited by other.
Cassels, et al., Analysis of Escherichia coli Colonization Factor Antigen I Linear B-Cell Epitopes, as Determined by Primate Responses, following Protein Sequence Verification, Infection and Immunity, Jun. 1992, pp. 2174-2181, vol. 60, No. 6. citedby other.
Romagnoli, et al. Peptide-MHC Interaction: A Rational Approach to Vaccine Design, Inter, RE. Immunol. 6, 1990, 00 61-73. cited by other.
Maister, First Oral AIDS Vaccine Trials Near, BioWorld Today, Tuesday, Apr. 19, 1994, p. 4. cited by other.
Rognan, et al., Molecular Modeling of an Antigenic Complex Between a Viral Peptide and a Class I Major Histocompatibility Glycoprotein, Proteins Structure, Function and Genetics 13 70-85 (1992). cited by other.
Brown, A hypothetical model of the foreign antigen blinding site of Class II histocompatibility molecules, Nature, vol. 332, Apr. 28, 1988, pp. 845-850. cited by other. |
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| Abstract: |
This invention relates to parenteral and mucosal vaccines against diseases caused by intercellular pathogens using antigens encapsulated within a biodegradable-biocompatible microspheres(matrix). |
| Claim: |
We claim:
1. An immunostimulating composition comprising .[.encapsulating.]. .Iadd.encapsulated .Iaddend.microspheres comprised of (a) a biodegradable-biocompatible.[.poly(DL-lactide-co-glycolideas.]. .Iadd.poly(DL-lactide-co-glycolide) as .Iaddend.the bulk matrix produced by a solvent evaporation process wherein the molecular weight of the copolymer is between 4,000 to 100,000 daltons and (b) an immunogenicsubstance consisting of a conformationally native subunit of chronic intracellular pathogen which, in the course of natural infection with that pathogen, is exposed to the host immune system on the surface of free pathogen and/or pathogen-infected cells.
2. The immunostimulating composition described in claim 1 wherein .Iadd.the immunogenic substance is an antigen and .Iaddend.the antigen is pre-encapsulated into a conformationally stabilizing hydrophilic matrix consisting of an appropriatemono, di- or tri-saccharide or other carbohydrate .[.susbstance.]. .Iadd.substance .Iaddend.by lyophilization prior to its final encapsulation into the PLG microsphere by a solvent extraction process employing acetonitrile as the polymer solvent,mineral oil as the emulsion's external phase, and heptane as the extractant.
3. The immunostimulating .[.compositions.]. .Iadd.composition .Iaddend.described in .[.claims.]. .Iadd.claim .Iaddend.1 .[.or 2.]. wherein the immunogenic substance is a native (oligomeric)HIV-1 envelope antigen that is conformationallystabilized by the polymer matrix and serves to elicit in animals the production of HIV specific cytotoxic T .[.lumphocytes.]. .Iadd.lymphocytes .Iaddend.and antibodies preferentially reactive against native HIV-1 envelope antigen.
4. The immunostimulating .[.compositions.]. .Iadd.composition .Iaddend.described in claim 3 wherein the amount of said immunogenic substance within the microcapsule comprises between 0.5% to 5.0% of the weight of said composition.
5. The immunostimulating .[.compositions describe.]. .Iadd.composition described .Iaddend.in claim 4 wherein the relative ratio between the amount of the lactide:glycolide components of said matrix is within the range of 52:48 to 0:100.
6. The immunostimulating .[.compositions.]. .Iadd.composition .Iaddend.described in claim 5 wherein the molecular weight of said copolymer is between 4,000 to 50,000 daltons.
7. A vaccine consisting of a blend of the immunostimulating .[.compositions described in claims 5 or 6 .]. .Iadd.composition of claim 5.Iaddend..
8. The immunostimulating .[.compositions.]. .Iadd.composition .Iaddend.described in claim 5, employed as a .[.parentally.]. .Iadd.parenterally .Iaddend.administered vaccine wherein the diameter size range of said vaccine microspheres liesbetween 1 nanometer and 20 microns.
9. The immunostimulating .[.compositions.]. .Iadd.composition .Iaddend.described in claim 5, employed as a mucosal vaccine wherein the size of more than 50% (by volume) of said vaccine microspheres is between 5 .Iadd.microns .Iaddend.to 10microns in diameter.
10. A composition in accordance with claim 1 wherein the microspheres further contain a pharmaceutically-acceptable adjuvant.
11. A vaccine consisting of a blend of the immunostimulating .[.compositions described in claims 5 or .]. .Iadd.composition of claim 6.Iaddend..
12. The immunostimulating .[.compositions.]. .Iadd.composition .Iaddend.described in claim 6 employed as a .[.parentally.]. .Iadd.parenterally .Iaddend.administered vaccine wherein the diameter size range of said vaccine microspheres liesbetween 1 nanometer and 20 microns.
13. The immunostimulating .[.compositions.]. .Iadd.composition .Iaddend.described in claim 7 employed as a .[.parentally.]. .Iadd.parenterally .Iaddend.administered vaccine wherein the diameter size range of said vaccine microspheres liesbetween .[.nanogram.]. .Iadd.nanometer .Iaddend.and 20 microns.
14. The immunostimulating .[.compositions.]. .Iadd.composition .Iaddend.described in claim 6 employed as a mucosal vaccine wherein the size of more than 50% (by volume) of said vaccine microspheres is between 5 .Iadd.microns .Iaddend.to 10microns in diameter. |
| Description: |
I. GOVERNMENT INTEREST
The invention descried herein may be manufactured, licensed and used by or for governmental purposes without the payment of any royalties to us thereon.
III. FIELD OF THE INVENTION
This invention relates to parenteral and mucosal vaccines against diseases cause by intracellular pathogens using antigens encapsulated within biodegradable-biocompatible microspheres(matrix).
IV. BACKGROUND OF THE INVENTION
Most infections by viruses and other intracellular pathogens are countered in the human host by a combination of humoral (antibody) and cellular (lymphocyte and phagocyte) immune effectors. Although the precise identity of immune effectorscapable of protecting the host against some chronic intracellular pathogens (e.g. HIV-1) remains unknown, attempts to develop preventive and therapeutic vaccines still focus on the induction of appropriate humoral and cellular immune responses. Furthermore, since most human viral pathogens (including HIV-1) are transmitted across mucosal surfaces, it is important that vaccines induce such responses locally (at the mucosal surface) as well as systemically and that they are durable for long-termprotection.
The issues of durability and mucosal immunogenicity have been previously addressed by encapsulating vaccine antigens in appropriately-sized biodegradable, biocompatible microspheres made of lactide/glycolide copolymer (the same materials used inresorbable sutures). It has been shown that such microspheres can be made to release their load in a controlled manner over a prolonged period of time and can facilitate the interaction of their contents with the local immune system when administratedmucosally.
In the case of HIV-1 infection, there is insufficient information at this time regrading the virus and its interactions with the human immune system to permit the rational design of a preventive vaccine. However, it has been noted that manycandidate HIV vaccines tested to date fail to elicit antibodies capable of neutralizing wild-type HIV-1 or binding to native HIV-1 proteins, fail to induce a substantial population of effector cells capable of destroying HIV-1-infected cells, and fail toinduce significant responses at mucosal surfaces. A possible approach to overcoming these problems (applicable to both HIV-1 and other chronic intracellular pathogens) is to identify a native protein, accessible to the immune system on the surface ofboth free virus and infected cells, and present it to the immune system (systemic and mucosal) encapsulated in microspheres to protect and augment its immunogenicity.
V. DESCRIPTION OF DRAWINGS
FIG. 1 indicates .[.control.]. .Iadd.cytotoxic T lymphocyte .Iaddend.induction in mice immunized with rgp 160; and
FIG. 2 indicates "Native"/denatured rgp 120 (IIIB) Binding Ratios.
V. DESCRIPTION OF THE INVENTION
This invention relates to a novel pharmaceutical composition, a microcapsule/sphere formulation, which comprises an antigen encapsulated within a biodegradable polymeric matrix, such as poly(DL-lactide co glycolide) (PLG), .Iadd.wherein themolecular weight of the PLG is about 4,000 to 100,000 daltons and .Iaddend.wherein the relative ratio between the lactide and glycolide component of the PLG is within the range of 52:48 to 0:100, and its use, as a vaccine, in the effective induction ofantiviral immune responses comprising both virus-specific cytotoxic T lymphocytes and antibodies reactive against native viral antigens. In the practice of this invention, applicants found that when a complex (oligomeric) native envelope protein ofHIV-1 was encapsulated in PLG microspheres, it retained its native antigenicity and function upon its release in vitro. Furthermore, when used as a vaccine in animals, this product elicited HIV-specific cytotoxic T lymphocytes and antibodies reactivewith native (oligomeric) HIV-1 envelope protein.
The following examples illustrate the invention:
EXAMPLE 1
Materials and Methods
Immunogens, Non-CD4-binding, baculo-expressed, recombinant gp 160.sub.IIIB (rgp 160) was obtained from MicroGeneSys (Meriden, Conn.). CD4-binding, oligomeric gp 160 CDC451 (o-gp 160) was obtained from Advanced BioScience Laboratories(Kensington, Md.).
Microencapsulation of immunogens: PLG microspheres ranging from 1 .Iadd.nanometer .Iaddend.to 20 um in diameter and containing a 0.5 to 1.0% antigen core load were prepared by a solvent extractive method. .Iadd.0.5 to 5.0% by weight antigen coreload could also be used. .Iaddend.The solvent extraction method involves dissolving the viral antigen and sucrose (1:4 ratio w:w) in 1 ml of deionized water. This solution is flash frozen and lyophilized. The resulting antigen-loaded sucrose particlesare resuspended in acetonitrile and mixed into PLG copolymer dissolved in acetonitrile. This antigen-polymer mixture is then emulsifyed into heavy mineral oil, transferred into heptane and mixed for 30 min to extract the oil and acetonitrile from thenascent spheres. The spheres are harvested by centrifugation, washed three times in heptane and dried overnight under vacuum. Microsphere size was determined by both light and scanning electron microscopy. The antigen core load was determined byquantitative amino acid analysis of the microspheres following complete hydrolysis in 6N hydrochloric acid.
Analysis of immunogen spontaneously released from microspheres in vitro by binding to soluble CD4 and recognition by HIV-positive patient serum. PLG microspheres loaded with native (oligomeric) gp 160 were suspended in phosphate-buffered saline,pH 7.4 (PBS), incubated at 37 C. for 3 h, and then at 4 C overnight. The microspheres were then sedimented by centrifugation (2 min at 200.times.g), the supernatants harvested, and the released gp 160 assayed for binding to CD4 and recognition byHIV-positive patient serum by surface plasmon resonance (described below). A sample of the stock protein used for microencapsulation was assayed for comparison.
Immunization of animals. HIV-seronegative, 8-10 week old NZW rabbits were immunized intramuscularly with rgp 160- or o-gp 160-loaded PLG microspheres suspended in PBS or with alum-adjuvanted rgp 160 in PBS. Groups receiving rgp 160-loadedmicrospheres (n=2) were primed with 50 ug of immunogen on day 0 and boosted with 25 ug on day 42. Groups receiving o-gp 160-loaded microspheres (n=3) were primed with 70 ug of immunogen on day 0 and boosted with 35 ug on day 56. Groups receivingalum-adjuvanted rgp 160 (n=2) got 85 ug of immunogen on days 0, 7, and 28.
BALB/c mice were immunized subcutaneously with rgp 160-loaded PLG microspheres suspend in PBS or with alum-adjuvanted rgp 160 in PBS. The mice in all groups (n=4) received 10 ug of immunogen on days 0 and 21.
Determination of the ratio of antibody binding to "native"/denatured rgp 120.sub.IIIB measured by surface plasmon resonance (SPR). Real-time binding interactions between ligand (gp 120 covalently linked to a biosensor matrix) and ligate (Abs insolution) were measured using surface plasmon resonance (BIAcore, Pharmacia Biosensor, Piscataway, N.J.). "Native"rgp 120(IIIB) (Genentech, South San Francisco, Calif.) or reduced, carboxymethylated (denatured) rgp 120(IIIB) (Genentech) was covalentlylinked to the biosensor dextran matrix. Sera and mAbs were diluted in HBS running buffer (10 mM HEPES, 150 mM NaCl, 3.4 mM EDTA, 0.05% (BIAcore) surfactant P20, pH 7.4) and injected through the dextran matrices at a flow rate of 5 ul/min. The bindingvalue of each serum or mAb was measured in resonance units (RU), and the "native"/denatured gp 120 ratios were determined by dividing the corresponding RU values and correcting for small differences in matrix concentration. Control included anHIV-positive patient serum and mAb 1c1.
Assessment of HIV-specific cell-mediated immunity in immunized mice by secondary CTL assay. The spleens of BALB/c mice immunized on days 0 and 21 were harvested and single cell suspensions prepared aseptically in complete RPMI medium on day 35. The cells were then pooled within experimental groups (n=4), underlay with ficoll, centrifuged 30 min at 450.times.g (RT), washed, and resuspended in complete RPMI medium. Following a 1 h stimulation with peptide p18 (1 uM) at 37.degree. C., the cellsuspensions were diluted with complete RPMI supplemented with 2ME (1:1000) and transferred to flasks for a 6 day incubation at 37.degree. C. After 2 days, recombinant IL-2 (10 u/ml) was added to all flasks. On day 6, P815 target cells were pulsed withpeptide p18 (1 uM) or with nothing (control) in PBS supplemented with 0.1% BSA. 3.times.10.sup.A6 target cells were labelled with 300 uCi of .sup.51Cr, washed, and plated out with the effector cells at effector:traget (E:T) ratios of 45:1, 15:1, 5:1,and 1.7:1. After a 6 h incubation at 37.degree. C., the supernatants were harvested and counted, and % specific lysis was calculated.
Results
Comparison of the native (oligomeric) gp 160 prior to microencapsulation and following spontaneous release from PLG microspheres showed the two to be essentially indistinguishable in terms of their binding to CD4 and recognition by HIV-positivepatient serum. (Table 1). This retention of conformation-dependent binding shows that structure of the antigen is not appreciably altered by the microencapsulation process.
FIG. 1 shows the data from a cytotoxic T lymphocyte (CTL) assay performed on the speen cells of mice which had had been previously immunized with either HIV-1 envelope protein encapsulated in PLG microspheres (dark squares) or the same proteinadministered in a conventional way with alum adjuvant (dark diamonds). These data indicate that microencapsulation of HIV-1 envelope protein in PLG microspheres results in a vaccine that induces significantly greater anti-HIV CTL activity than doesalum-adjuvanted vaccine. The open symbol groups represent controls run to assure that the activity being measured is virus-specific.
FIG. 2 shows the results of an assay designed to measure the relative binding of antibodies to native vs denatured viral protein. These data show that rabbits immunized with a non-native HIV-1 protein encapsulated in PLG (#5 and 6) developantibodies which show greater binding to denatured (vs native) protein (indicated by a ratio<1). On the other hand, rabbits immunized with a native HIV-1 protein encapsulated in PLG microspheres (#10-12) develop antibodies which show greater bindingto native viral protein (indicated by ratio>1). This retention of each proteins antigenicity constitutes an additional piece of evidence that the structure of antigens loaded in PLG microspheres are preserved.
EXAMPLE 2
Materials and Methods
This experiment was similar to that described in Example 1 except for the method of microencapsulation employed.
Microencapsulation of immunogens: PLG microspheres ranging from 1 to 15 um in diameter and containing a 0.5 to 1.0% antigen core load were prepared by a solvent evaporation method. The solvent evaporation method involves emulsifying the viralantigen dissolved in deionized water into poly(DL-lactide-co-glycolide) polymer dissolved in methylene chloride. This emulsion is mixed into 0.9% polyvinyl alcohol and stirred. After 10 min of stirring, 0.35 l of water is added and gentle mixing iscontinued for 1.5 h. The resulting spheres are harvested by centrifugation, washed three times in distilled water, and dried overnight under vacuum. Microsphere size was determined by both light and scanning electron microscopy. The antigen core loadwas determined by quantitative amino acid analysis of the microspheres following complete hydrolysis in 6N hydrochloric acid.
Results
Analysis of spontaneously released antigen showed it to retain its CD4 binding capacity. Its native antigenicity (recognition by the serum of an HIV-positive patient) was only slightly less than that of the antigen prior to encapsulation andfollowing spontaneous release from microspheres produced by a solvent extraction method (Table 1).
The results of immunizing animals with either non-native (denatured) or native oligomeric gp 160 in PLG microspheres produced by a solvent evaporation method were essentially indistinguishable from those obtained using microspheres produced by asolvent extraction method (example 1). Microencapsulated antigen induced significantly greater CTL activity than antigen administered in a conventional alum-adjuvanted formulation. Furthermore, preservation of the structure of PLG-microencapsulatedantigens is supported by the findings of preferential binding of antibodies elicited by microspheres loaded with denatured antigen to denatured gp 120 .[.(FIGS. 2, 3, and 4).]. .Iadd.(FIG. 2, nos. 3 and 4) .Iaddend.and the preferred binding ofantibodies elicited by microspheres loaded with native (oligomeric) antigen to native gp 120 .[.(FIGS. 2, 7-8).]. .Iadd.(FIG. 2, nos. 7 and 8).Iaddend..
TABLE-US-00001 TABLE 1 BIA (released o-gp160) Capture o-gp160-451 (stock vs microsphere-released) on tvc 391 fc3/fc4 sCD4 (4 mg/m) 1 ul/min flow rate foe o-gp160 ini.: 5 ul/min for all others ligate RU HIV+/sCD4 (RU ratio) gp120-MN 1:10 3286HIV+ 1:100 54 NHS 1:100 3 HIV+ pool 1:100 47 o-gp160 (tvc281) 1772 HIV+ 3259 1.84 tvc281 1848 NHS -36 tvc281 1762 HIV+ pool 2597 1.47 tvc281-PLG-EV 3342 HIV+ 4594 1.37 tvc281 3222 NHS 7 tvc281 3210 HIV+ pool 3336 1.04 tvc281-PLG-EX 1855 HIV+ 3760 2.04tvc281 1839 NHS 2 tvc281 1850 HIV+ pool 2745 1.48 gp120-MN 1:10 2914 HIV+ 1:100 14 NHS 1:100 -2 HIV+ pool 1:100 14 tvc281 1099 HIV+ 1083 0.99 tvc281 1022 HIV+ pool 1395 1.36 tvc281-PLG-EV 1595 HIV+ 1322 0.83 tvc281 1535 HIV+ pool 1781 1.16
In view of the above it will be seen that the objects of the invention are achieved. As various changes could be made in the above materials and methods without departing from the scope of the invention, it is intended that all matter containedin the above description shall be interpreted as illustrative and not limiting.
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