Sperm-based contraceptive vaccines: Current status, merits and development

Expert Reviews in Molecular Medicine

Volumn 7, Issue 18, 2005, Pages 1-16

  Suri, Anil ^a  

^a NATIONAL INSTITUTE OF IMMUNOLOGY   (India)

Author keywords

[No Author keywords available]

Indexed keywords

ANTIBODY; CELL PROTEIN; CONTRACEPTIVE VACCINE; SPERM ANTIGEN; SPERMICIDAL AGENT;

CELL SPECIFICITY; DRUG TARGETING; FERTILIZATION; GROWTH RATE; HUMAN; IMMUNOCONTRACEPTION; IMMUNOGENICITY; NONHUMAN; POPULATION GROWTH; PRIORITY JOURNAL; REVIEW; SPERMATOZOON;

ANIMALS; DRUG DESIGN; HUMANS; MALE; SPERMATOZOA; VACCINES, CONTRACEPTIVE;

EID: 29244481823     PISSN: 14623994     EISSN: 14623994     Source Type: Journal    
DOI: 10.1017/S1462399405009877     Document Type: Review

References (118)

1. United Nations Population Information Network. http://www.un.org/popin
2. Delves, P.J., Lund, T. and Roitt, I.M. (2002) Antifertility vaccines. Trends Immunol 23, 213-219, PubMed: 11923117
3. Van Voorhis, B.J. and Stovall, D.W. (1997) Autoantibodies and infertility: A review of the literature. J Reprod Immunol 33, 239-256, PubMed: 9255726
4. Shankar, S., Mohapatra, B. and Suri, A. (1998) Cloning of a novel human testis mRNA specifically expressed in testicular haploid germ cells, having unique palindromic sequences and encoding a leucine zipper dimerization motif. Biochem Biophys Res Commun 243, 561-565, PubMed: 9480848
5. Shetty, J. et al. (1999) Human sperm proteome: Immunodominant sperm surface antigens identified with sera from infertile men and women. Biol Reprod 61, 61-69, PubMed: 10377032
6. Cheng, C.Y. et al. (2001) Two new male contraceptives exert their effects by depleting germ cells prematurely from the testis. Biol Reprod 65, 449-461, PubMed: 11466213
7. Davis, J. and Pollack A.E. (1994) Vasectomy. In Fertility Control (2nd edn) (Corsori, S.L., Derman, R.J. and Tyrer, L.B., eds), pp. 319-338, Goldin Publishers
8. Puri, C.P., Gopalkrishnan, K. and Iyer, K.S. (2000) Constraints in the development of contraceptives for men. Asian J Androl 2, 179-190, PubMed: 11225976
9. Schellstede, W.P., Feinberg, M.P. and Dallabetta, G. (2000) Condom availability: Barriers to access, barriers to use. In Condoms (Mindel, A., eds), pp. 160-174, BMJ Books, London
10. Tulsiani, D.R. and Abou-Haila, A. (2001) Mammalian sperm molecules that are potentially important in interaction with female genital tract and egg vestments. Zygote 9, 51-69, PubMed: 11273033
11. Bohring, C., Klepper, L. and Krause, W. (2004) Localization of binding sites of naturally occuring antisperm antibodies on human spermatozoa by immunofluorescence. Andrologia 36, 286-290, PubMed: 15458547
12. Mahony, M.C. and Alexander, N.J. (1991) Sites of antisperm antibody action. Hum Reprod 6, 1426-1430, PubMed: 1770139
13. Tasdemir, I. et al. (1995) Effect on sperm-immobilizing antibodies on the spontaneous and calcium-ionophore (A23187)-induced acrosome reaction. Int J Fertil Menopausal Stud 40, 192-195, PubMed: 8520620
14. Francavilla, F., Romano, R. and Santucci, R. (1991) Effect of sperm-antibodies on acrosome reaction of human sperm used for the hamster egg penetration assay. Am J Reprod Immunol 25, 77-80, PubMed: 1872955
15. Liu, D.Y. and Baker, H.W. (1992) Tests of human sperm function and fertilization in vitro. Fertil Steril 58, 465-483, PubMed: 1521638
16. Wolf, J.P. et al. (1995) High levels of sperm-associated antibodies impair human spermoolemma interaction after subzonal insemination. Fertil Steril 63, 584-590, PubMed: 7851591
17. Naz, R.K. (1992) Effects of antisperm antibodies on early cleavage of fertilized ova. Biol Reprod 46, 130-139, PubMed: 1547310
18. Naz, R.K. and Menge, A.C. (1994) Antisperm antibodies: Origin, regulation, and sperm reactivity in human infertility. Fertil Steril 61, 1001-1013, PubMed: 8194608
19. D'Cruz, O.J. et al. (1991) Activation of human complement by IgG antisperm antibody and the demonstration of C3 and C5b-9-mediated immune injury to human sperm. J Immunol 146, 611-620, PubMed: 1987279
20. Rooney, I.A., Oglesby, T.J. and Atkinson, J.P. (1993) Complement in human reproduction: Activation and control. Immunol Res 12, 276-294, PubMed: 8288946
21. Allegrucci, C. et al. (2001) Circulating human antisperm antibodies recognize prostasomes. Am J Reprod Immunol 46, 211-219, PubMed: 11554694
22. Brown, P.R. et al. (2003) A-kinase anchoring protein 4 binding proteins in the fibrous sheath of the sperm flagellum. Biol Reprod 68, 2241-2248, PubMed: 12606363
23. Vijayaraghavan, S. et al. (1997) Protein kinase A-anchoring inhibitor peptides arrest mammalian sperm motility. J Biol Chem 272, 4747-4752, PubMed: 9030527
24. Luconi, M. et al. (2001) Phosphatidylinositol 3-kinase inhibition enhances human sperm motility. Hum Reprod 16, 1931-1937, PubMed: 11527900
25. Luconi, M. et al. (2005) Tyrosine phosphorylation of the a kinase anchoring protein 3 (AKAP3) and soluble adenylate cyclase are involved in the increase of human sperm motility by bicarbonate. Biol Reprod 72, 22-32, PubMed: 15342355
26. Miki, K. et al. (2002) Targeted disruption of the Akap4 gene causes defects in sperm flagellum and motility. Dev Biol 248, 331-342, PubMed: 12167408
27. Baldi, E. et al. (1996) Human sperm activation during capacitation and acrosome reaction: Role of calcium, protein phosphorylation and lipid remodelling pathways. Front Biosci 1, d189-205, PubMed: 9159227
28. Storey, B.T. (1995) Interactions between gametes leading to fertilization: The sperm's eye view. Reprod Fertil Dev 7, 927-942, PubMed: 8711224
29. Visconti, P.E. and Kopf, G.S. (1998) Regulation of protein phosphorylation during sperm capacitation. Biol Reprod 59, 1-6, PubMed: 9674985
30. White, D.R. and Aitken, R.J. (1989) Relationship between calcium, cyclic AMP, ATP, and intracellular pH and the capacity of hamster spermatozoa to express hyperactivated motility. Gamete Res 22, 163-177, PubMed: 2540081
31. Darszon, A. et al. (1999) Ion channels in sperm physiology. Physiol Rev 79, 481-510, PubMed: 10221988
32. Suri, A. (2004) Sperm specific proteins-potential candidate molecules for fertility control. Reprod Biol Endocrinol 2, 10, PubMed: 15012833
33. Suri, A. (2005) Contraceptive vaccines targeting sperm. Expert Opin Biol Ther 5, 381-392, PubMed: 15833075
34. Jagadish, N. et al. (2005) Characterization of a novel human sperm-associated antigen 9 (SPAG9) having structural homology with c-Jun N-terminal kinase-interacting protein. Biochem J 389, 73-82, PubMed: 15693750
35. Morrison, D.K. and Davis, R.J. (2003) Regulation of MAP kinase signaling modules by scaffold proteins in mammals. Annu Rev Cell Dev Biol 19, 91-118, PubMed: 14570565
36. Jagadish, N. et al. (2005) Characterization of immune response in mice to plasmid DNA encoding human sperm associated antigen 9 (SPAG9). Vaccine PubMed: 16061308
37. Shankar, S. et al. (2004) Isolation and characterization of a haploid germ cell specific sperm associated antigen 9 (SPAG9) from the baboon. Mol Reprod Dev 69, 186-193, PubMed: 15293220
38. Jagadish, N. et al. (2005) Molecular cloning and characterization of the macaque sperm associated antigen 9 (SPAG9): An orthologue of human SPAG9. Mol Reprod Dev 71, 58-66, PubMed: 15736136
39. Lathrop, W.F. et al. (1990) cDNA cloning reveals the molecular structure of a sperm surface protein, PH-20, involved in sperm-egg adhesion and the wide distribution of its gene among mammals. J Cell Biol 111, 2939-2949, PubMed: 9969661
40. Zhang, H. et al. (2004) Spam1 (PH-20) expression in the extratesticular duct and accessory organs of the mouse: A possible role in sperm fluid reabsorption. Biol Reprod 71, 1101-1107, PubMed: 15175239
41. Shalgi, R. et al. (1990) Antigens on rat spermatozoa with a potential role in fertilization. Mol Reprod Dev 25, 286-296, PubMed: 2184854
42. ten Have, J., Beaton, S. and Bradley, M.P. (1998) Cloning and characterization of the cDNA encoding the PH20 protein in the European red fox Vulpes vulpes. Reprod Fertil Dev 10, 165-172, PubMed: 9801268
43. Holland, M.K. et al. (1997) Selection of antigens for use in a virus-vectored immunocontraceptive vaccine: PH-20 as a case study. Reprod Fertil Dev 9, 117-124, PubMed: 9109201
44. Evans, E.A., Zhang, H. and Martin-DeLeon, P.A. (2003) SPAM1 (PH-20) protein and mRNA expression in the epididymides of humans and macaques: utilizing laser microdissection/RT-PCR. Reprod Biol Endocrinol 1, 54, PubMed: 12932297
45. Primakoff, P. et al. (1988) Fully effective contraception in male and female guinea pigs immunized with the sperm protein PH-20. Nature 335, 543-546, PubMed: 3419530
46. Hardy, C.M. et al. (2004) Assessment of contraceptive vaccines based on recombinant mouse sperm protein PH20. Reproduction 127, 325-334, PubMed: 15016952
47. Phelps, B.M. et al. (1990) Evidence that proteolysis of the surface is an initial step in the mechanism of formation of sperm cell surface domains. J Cell Biol 111, 1839-1847, PubMed: 2229175
48. Seaton, G.J., Hall, L. and Jones, R. (2000) Rat sperm 2B1 glycoprotein (PH20) contains a C-terminal sequence motif for attachment of a glycosyl phosphatidylinositol anchor. Effects of endoproteolytic cleavage on hyaluronidase activity. Biol Reprod 62, 1667-1676, PubMed: 10819770
49. Deng, X., Czymmek, K. and Martin-DeLeon, P.A. (1999) Biochemical maturation of Spam1 (PH-20) during epididymal transit of mouse sperm involves modifications of N-linked oligosaccharides. Mol Reprod Dev 52, 196-206, PubMed: 9890751
50. Tung, K.S. et al. (1997) Mechanism of infertility in male guinea pigs immunized with sperm PH-20. Biol Reprod 56, 1133-1141, PubMed: 9160711
51. Pomering, M. et al. (2002) Restricted entry of IgG into male and female rabbit reproductive ducts following immunization with recombinant rabbit PH-20. Am J Reprod Immunol 47, 174-182, PubMed: 12069203
52. Primakoff, P. et al. (1997) Reversible contraceptive effect of PH-20 immunization in male guinea pigs. Biol Reprod 56, 1142-1146, PubMed: 9160712
53. Hao, Z. et al. (2002) SAMP32, a testis-specific, isoantigenic sperm acrosomal membrane-associated protein. Biol Reprod 66, 735-744, PubMed: 11870081
54. Shetty, J. et al. (2003) SAMP14, a novel, acrosomal membrane-assodated, glycosylphosphatidylinositol-anchored member of the Ly-6/urokinase-type plasminogen activator receptor superfamily with a role in sperm-egg interaction. J Biol Chem 278, 30506-30515, PubMed: 12788941
55. Yanagimachi, R. and Noda, Y.D. (1970) Ultrastructural changes in the hamster sperm head during fertilization. J Ultrastruct Res 31, 465-485, PubMed: 4912966
56. Wolkowicz, M.J. et al. (2003) Equatorial segment protein defines a discrete acrosomal subcompartment persisting throughout acrosomal biogenesis. Biol Reprod 69, 735-745, PubMed: 12773409
57. Noor, M.M. and Moore, H.D. (1999) Monoclonal antibody that recognizes an epitope of the sperm equatorial region and specifically inhibits spermoolemma fusion but not binding. J Reprod Fertil 115, 215-224, PubMed: 10434926
58. Auer, J. et al. (2000) Isolation and characterisation of two sperm membrane proteins recognised by sperm-associated antibodies in infertile men. Mol Reprod Dev 57, 393-405, PubMed: 11066069
59. Toshimori, K. et al. (1992) Characterization of the antigen recognized by a monoclonal antibody MN9: Unique transport pathway to the equatorial segment of sperm head during spermiogenesis. Cell Tissue Res 270, 459-468, PubMed: 1486600
60. Coonrod, S.A., Westhusin, M.E. and Naz, R.K. (1994) Monoclonal antibody to human fertilization antigen-1 (FA-1) inhibits bovine fertilization in vitro: Application in immunocontraception. Biol Reprod 51, 14-23, PubMed: 7918868
61. Naz, R.K., Ahmad, K. and Menge, A.C. (1993) Antiidiotypic antibodies to sperm in sera of fertile women that neutralize antisperm antibodies. J Clin Invest 92, 2331-2338, PubMed: 8227348
62. Menge, A.C. et al. (1999) Fertilization antigen-1 removes antisperm autoantibodies from spermatozoa of inferfile men and results in increased rates of acrosome reaction. Fertil Steril 71, 256-260, PubMed: 9988394
63. Naz, R.K., Brazil, C. and Overstreet, J.W. (1992) Effects of antibodies to sperm surface fertilization antigen-1 on human sperm-zona pellucida interaction. Fertil Steril 57, 1304-1310, PubMed: 1601155
64. Naz, R.K. and Zhu, X. (1998) Recombinant fertilization antigen-1 causes a contraceptive effect in actively immunized mice. Biol Reprod 59, 1095-1100, PubMed: 9780314
65. Trivedi, R.N. and Naz, R.K. (2002) Testis-specific antigen (TSA-1) is expressed in murine sperm and its antibodies inhibit fertilization. Am J Reprod Immunol 47, 38-45, PubMed: 11883748
66. Santhanam, R. and Naz, R.K. (2001) Novel human testis-specific cDNA: molecular cloning, expression and immunobiological effects of the recombinant protein. Mol Reprod Dev 60, 1-12, PubMed: 11550262
67. Yuan, R., Primakoff, P. and Myles, D.G. (1997) A role for the disintegrin domain of cyritestin, a sperm surface protein belonging to the ADAM family, in mouse sperm-egg plasma membrane adhesion and fusion. J Cell Biol 137, 105-112, PubMed: 9105040
68. Evans, J.P. (2001) Fertilin beta and other ADAMs as integrin ligands: insights into cell adhesion and fertilization. Bioessays 23, 628-639, PubMed: 11462216
69. Hardy, C.M. et al. (1997) Examination of the immunocontraceptive potential of recombinant rabbit fertilin subunits in rabbit. Biol Reprod 57, 879-886, PubMed: 9314593
70. Bedford, J.M. (1975) Maturation, transport and fate of spermatozoa in the epididymis. In Handbook of Physiology (Vol. 5) (Hamilton, D.W. and Greep, R.O., eds), pp. 303-317, American Physiological Society
71. Hinton, B.T. et al. (1995) In Handbook of Andrology (Lawrence, K.S., eds), pp. 18-20, The American Society of Andrology,
72. Orgebin-Crist, M-C., Danzo, B.J. and Davies, J. (1975) Endocrine control of the development and maintenance of sperm fertilizing ability in the epididymis. In Handbook of Physiology (Vol. 5) (Hamilton, D.W. and Greep, R.O., eds), pp. 319-338, American Physiological Society
73. Cooper, T.G. and Yeung, C.H. (1999) Approaches to post-testicular contraception. Asian J Androl 1, 29-36, PubMed: 11225901
74. Lasserre, A. et al. (2001) Human epididymal proteins and sperm function during fertilization: Un update. Biol Res 34, 165-178, PubMed: 11715855
75. Richardson, R.T. et al. (2001) Cloning and sequencing of human Eppin: A novel family of protease inhibitors expressed in the epididymis and testis. Gene 270, 93-102, PubMed: 11404006
76. Wang, Z. et al. (2005) Association of eppin with semenogelin on human spermatozoa. Biol Reprod 72, 1064-1070, PubMed: 15590901
77. Robert, M. and Gagnon, C. (1995) Sperm motility inhibitor from human seminal plasma: Association with semen coagulum. Hum Reprod 10, 2192-2197, PubMed: 8567872
78. Robert, M. and Gagnon, C. (1996) Purification and characterization of the active precursor of a human sperm motility inhibitor secreted by the seminal vesicles: Identity with semenogelin. Biol Reprod 55, 813-821, PubMed: 8879494
79. de Lamirande, E. et al. (2001) Semenogelin, the main protein of semen coagulum, inhibits human sperm capacitation by interfering with the superoxide anion generated during this process. J Androl 22, 672-679, PubMed: 11451365
80. O'Rand M, G. et al. (2004) Reversible immunocontraception in male monkeys immunized with eppin. Science 306, 1189-1190, PubMed: 15539605
81. Rochwerger, L. and Cuasnica, P.S. (1992) Redistribution of a rat sperm epididymal glycoprotein after in vitro and in vivo capacitation. Mol Reprod Dev 31, 34-41, PubMed: 1562325
82. Cohen, D.J. et al. (2000) Relationship between the association of rat epididymal protein "DE" with spermatozoa and the behavior and function of the protein. Mol Reprod Dev 56, 180-188, PubMed: 10813850
83. Yanagimachi, R. (1988) Sperm-egg fusion. In Current Topics in Membranes and Transport (Duzgunes, N. and Bronner, F., eds), pp. 3-43, Academic Press, Orlando, FL
84. Perez Martinez, S., Conesa, D. and Cuasnicu, P.S. (1995) Potential contraceptive use of epididymal proteins: Evidence for the participation of specific antibodies against rat epididymal protein DE in male and female fertility inhibition. J Reprod Immunol 29, 31-45, PubMed: 8531190
85. Ellerman, D.A. et al. (1998) Potential contraceptive use of epididymal proteins: Immunization of male rats with epididymal protein DE inhibits sperm fusion ability. Biol Reprod 59, 1029-1036, PubMed: 9780306
86. Li, P. et al. (2001) An antimicrobial peptide gene found in the male reproductive system of rats. Science 291, 1783-1785, PubMed: 11230693
87. Quayle, A.J. et al. (1998) Gene expression, immunolocalization, and secretion of human defensin-5 in human female reproductive tract. Am J Pathol 152, 1247-1258, PubMed: 9588893
88. Lehrer, R.I. and Ganz, T. (1999) Antimicrobial peptides in mammalian and insect host defence. Curr Opin Immunol 11, 23-27, PubMed: 10047545
89. Garcia, J.R. et al. (2001) Identification of a novel, multifunctional beta-defensin (human beta-defensin 3) with specific antimicrobial activity. Its interaction with plasma membranes of Xenopus oocytes and the induction of macrophage chemoattraction. Cell Tissue Res 306, 257-264, PubMed: 11702237
90. Goldberg, E. and Shelton, J.A. (1986) Immunologic properties of LDH-C4 for contraceptive vaccine development. In Male Contraception Advances and Future Prospects (Zatuchni, G.I. et al., eds), pp. 435-446, Harper and Row
91. O'Hern, P.A. et al. (1995) Reversible contraception in female baboons immunized with a synthetic epitope of sperm-specific lactate dehydrogenase. Biol Reprod 52, 331-339, PubMed: 7536050
92. O'Hern, P.A. et al. (1997) Colinear synthesis of an antigen-specific B-cell epitope with a 'promiscuous' tetanus toxin T-cell epitope: A synthetic peptide immunocontraceptive. Vaccine 15, 1761-1766, PubMed: 9364680
93. Tollner, T.L. et al. (2002) Immunization of female cynomolgus macaques with a synthetic epitope of sperm-specific lactate dehydrogenase results in high antibody titers but does not reduce fertility. Mol Reprod Dev 62, 257-264, PubMed: 11984836
94. Herrera, M.A. et al. (1992) Protection against malaria in Aotas monkeys immunized with a recombinant blood-stage antigen fused to a universal T-cell epitope: Correlation of serum gamma interferon levels with protection. Infect Immun 60, 154-158, PubMed: 1370271
95. Boulanger, D. et al. (1991) Immunization of mice and baboons with the recombinant Sm28GST affects both worm viability and fecundity after experimental infection with Schistosoma mansoni. Parasite Immunol 13, 473-490, PubMed: 1956696
96. Scott, P. et al. (1987) Vaccination against cutaneous leishmaniasis in a murine model. II. Immunologic properties of protective and nonprotective subtractions of soluble promastigote extract. J Immunol 139, 3118-3125, PubMed: 3499465
97. Scott, P. et al. (1989) Role of cytokines and CD4+ T-cell subsets in the regulation of parasite immunity and disease. Immunol Rev 112, 161-182, PubMed: 2575073
98. Good, M.F. and Miller, L.H. (1989) Involvement of T cells in malaria immunity: Implications for vaccine development. Vaccine 7, 3-9, PubMed: 2655342
99. Naz, R.K. and Mehta, K. (1989) Cell-mediated immune responses to sperm antigens: Effects on mouse sperm and embryos. Biol Reprod 41, 533-542, PubMed: 2590718
100. Cunningham, D.S. (1993) Induction and measurement of antisperm antibody responses in vitro. Gynecol Obstet Invest 36, 193-197, PubMed: 8300001
101. Ferro, V.A. (2002) Current advances in antifertility vaccines for fertility control and noncontraceptive applications. Expert Rev Vaccines 1, 443-452, PubMed: 12901582
102. Valmori, D. et al. (2003) Simultaneous CD8+ T cell responses to multiple tumor antigen epitopes in a multipeptide melanoma vaccine. Cancer Immun 3, 15, PubMed: 14580186
103. Smith, S.G. (1999) The polyepitope approach to DNA vaccination. Curr Opin Mol Ther 1, 10-15, PubMed: 11249673
104. Suhrbier, A. (2002) Polytope vaccines for the codelivery of multiple CD8 T-cell epitopes. Expert Rev Vaccines 1, 207-213, PubMed: 12901559
105. Domagala, A. and Kurpisz, M. (2001) CD52 antigen - a review. Med Sci Monit 7, 325-331, PubMed: 11257744
106. Bach, J.F., Koutouzov, S. and van Endert, P.M. (1998) Are there unique autoantigens triggering autoimmune diseases? Immunol Rev 164, 139-155, PubMed: 9795772
107. Hardy, C.M., Clydesdale, G. and Mobbs, K.J. (2004) Development of mouse-specific contraceptive vaccines: Infertility in mice immunized with peptide and polyepitope antigens. Reproduction 128, 395-407, PubMed: 15454634
108. O'Rand, M.G. et al. (1993) Inhibition of fertility in female mice by immunization with a B-cell epitope, the synthetic sperm peptide, P10G. J Reprod Immunol 25, 89-102, PubMed: 7513024
109. Vanage, G. et al. (1992) Infertility induced in rats by immunization with synthetic peptide segments of a sperm protein. Biochem Biophys Res Commun 183, 538-543, PubMed: 1550561
110. Lou, Y. et al. (1995) A zona pellucida 3 peptide vaccine induces antibodies and reversible infertility without ovarian pathology. J Immunol 155, 2715-2720, PubMed: 7650399
111. Pique, L. et al. (1978) Specificity of anti-LH-RH antisera induced by different immunogens. Immunochemistry 15, 55-60, PubMed: 75175
112. Briand, J.P., Muller, S. and Van Regenmortel, M.H. (1985) Synthetic peptides as antigens: Pitfalls of conjugation methods. J Immunol Methods 78, 59-69, PubMed: 2580027
113. Herzenberg, L.A. and Tokuhisa, T. (1980) Carrier-priming leads to hapten-specific suppression. Nature 285, 664-667, PubMed: 6967189
114. Schutze, M.P. et al. (1989) Carrier-induced epitopic suppression is initiated through clonal dominance. J Immunol 142, 2635-2640, PubMed: 2467933
115. Lea, I.A. et al. (1998) A chimeric sperm peptide induces antibodies and strain-specific reversible infertility in mice. Biol Reprod 59, 527-536, PubMed: 9716550
116. Srinivasan, J. et al. (1995) Oral immunization with attenuated Salmonella expressing human sperm antigen induces antibodies in serum and the reproductive tract. Biol Reprod 53, 462-471, PubMed: 7492701
117. Wahren, B. (1996) Gene vaccines. Immunotechnology 2, 77-83, PubMed: 9373316
118. Montgomery, D.L. et al. (1997) DNA vaccines. Pharmacol Ther 74, 195-205, PubMed: 9336022