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Naz RK, Saver AE. Immunocontraception for Animals: Current Status and Future Perspective. Am J Reprod Immunol 2015; 75:426-39. [PMID: 26412331 DOI: 10.1111/aji.12431] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2015] [Accepted: 09/01/2015] [Indexed: 01/09/2023] Open
Abstract
An alternative to surgical sterilization for fertility control of animals (wild, zoo, farm, and domestic) is needed to prevent problems related to overpopulation, including culling and relocation. A PubMed and Google Scholar database search was conducted using the keywords 'contraceptive vaccine animals,' 'immunocontraception animals,' 'non-surgical sterilization animals,' 'PZP vaccine,' and 'GnRH vaccine.' The searches from 1972 to 2015 yielded over 1500 publications. These articles were read, and 375 were selected for detailed analysis. Articles referenced in these publications were also thoroughly examined. PZP and GnRH contraceptive vaccines (CVs) have been extensively investigated for fertility control of wild, zoo, farm, and domestic animal populations. Both vaccines have shown tremendous success with PZP vaccines taking the lead. Novel technologies and targets are being developed to improve existing vaccines and generate second-generation CVs. Single-shot vaccines, which can be delivered remotely, will greatly advance the field of immunocontraception for animal use with potential human application.
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Affiliation(s)
- Rajesh K Naz
- Reproductive Immunology and Molecular Biology Laboratory, Department of Obstetrics and Gynecology, School of Medicine, West Virginia University, Morgantown, WV, USA
| | - Ashley E Saver
- Reproductive Immunology and Molecular Biology Laboratory, Department of Obstetrics and Gynecology, School of Medicine, West Virginia University, Morgantown, WV, USA
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Gupta SK, Malik A, Arukha AP. Ovarian and oocyte targets for development of female contraceptives. Expert Opin Ther Targets 2015; 19:1433-46. [DOI: 10.1517/14728222.2015.1051305] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Kaur K, Prabha V. Immunocontraceptives: new approaches to fertility control. BIOMED RESEARCH INTERNATIONAL 2014; 2014:868196. [PMID: 25110702 PMCID: PMC4119744 DOI: 10.1155/2014/868196] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/28/2014] [Accepted: 06/10/2014] [Indexed: 11/24/2022]
Abstract
The rapidly increasing global population has bowed the attention of family planning and associated reproductive health programmes in the direction of providing a safe and reliable method which can be used to limit family size. The world population is estimated to exceed a phenomenal 10 billion by the year 2050 A.D., thus presenting a real jeopardy of overpopulation with severe implications for the future. Despite the availability of contraceptive methods, there are over one million elective abortions globally each year due to unintended pregnancies, having devastating impact on reproductive health of women worldwide. This highlights the need for the development of newer and improved contraceptive methods. A novel contraceptive approach that is gaining substantial attention is "immunocontraception" targeting gamete production, gamete outcome, or gamete function. Amongst these, use of sperm antigens (gamete function) seems to be an exciting and feasible approach. However, the variability of immune response and time lag to attain titer among vaccinated individuals after active immunization has highlighted the potential relevance of preformed antibodies in this league. This review is an attempt to analyze the current status and progress of immunocontraceptive approaches with respect to their establishment as a future fertility control agent.
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Affiliation(s)
- Kiranjeet Kaur
- Department of Microbiology, Panjab University, Chandigarh 160014, India
| | - Vijay Prabha
- Department of Microbiology, Panjab University, Chandigarh 160014, India
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Abstract
The National Wildlife Research Center (NWRC) began immunocontraception vaccine research by testing porcine zona pellucida (PZP) on white-tailed deer (Odocoileus virginianus). Early PZP research demonstrated that PZP induced infertility; however, increased length of the rut was observed in PZP-treated deer. An alternative vaccine using a keyhole limpet hemocyanin-gonadotropin-releasing hormone (KLH-GnRH) conjugate formulated with modified Freund's adjuvant was developed at NWRC. Suppression of GnRH has reduced reproduction in both sexes but is most effective in females. This vaccine was effective in preventing contraception in female deer for several years after a prime and boost. Due to adverse side effects of Freund's adjuvant, NWRC developed a new adjuvant called AdjuVac, a mineral oil/surfactant adjuvant with the addition of Mycobacterium avium as an immunostimulant. The price of KLH prompted a search for a more economical hemocyanin carrier protein for the GnRH peptide. Blue protein, derived from the mollusk Concholepas concholepas, proved to be a successful option. Formulation improvements resulted in a vaccine that can be effective as a single injection for multiple years, now called GonaCon. GonaCon is registered with the Environmental Protection Agency (EPA) for use in white-tailed deer in urban/suburban areas and for wild horses (Equus caballus) and burros (Equus asinus). Future GonaCon applications may include reducing reproduction to manage populations of other wildlife species, such as prairie dogs (Cynomys ludovicianus) in urban areas and suppressing reproduction to reduce the spread of venereal diseases such as brucellosis. Research is being conducted to develop a GnRH vaccine used in combination with the rabies vaccine to control population growth in free-roaming dogs, with the secondary effect of managing the spread of rabies. The EPA would regulate all these uses. Research is also ongoing on a GnRH vaccine to delay the onset of adrenocortical disease in pet ferrets (Mustela putorius), a use regulated by the United States Department of Agriculture.
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Kobayashi K, Asano M, Yanagawa Y, Haneda S, Matsui M. An Attempt to Induce Antibody Production for Immunocontraception in the Hokkaido Sika Deer (Cervus nippon yesoensis) by Immunization with a Porcine Zona Pellucida Synthetic Peptide. MAMMAL STUDY 2014. [DOI: 10.3106/041.039.0110] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Massei G, Cowan D. Fertility control to mitigate human–wildlife conflicts: a review. WILDLIFE RESEARCH 2014. [DOI: 10.1071/wr13141] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
As human populations grow, conflicts with wildlife increase. Concurrently, concerns about the welfare, safety and environmental impacts of conventional lethal methods of wildlife management restrict the options available for conflict mitigation. In parallel, there is increasing interest in using fertility control to manage wildlife. The present review aimed at analysing trends in research on fertility control for wildlife, illustrating developments in fertility-control technologies and delivery methods of fertility-control agents, summarising the conclusions of empirical and theoretical studies of fertility control applied at the population level and offering criteria to guide decisions regarding the suitability of fertility control to mitigate human–wildlife conflicts. The review highlighted a growing interest in fertility control for wildlife, underpinned by increasing numbers of scientific studies. Most current practical applications of fertility control for wild mammals use injectable single-dose immunocontraceptive vaccines mainly aimed at sterilising females, although many of these vaccines are not yet commercially available. One oral avian contraceptive, nicarbazin, is commercially available in some countries. Potential new methods of remote contraceptive delivery include bacterial ghosts, virus-like particles and genetically modified transmissible and non-transmissible organisms, although none of these have yet progressed to field testing. In parallel, new species-specific delivery systems have been developed. The results of population-level studies of fertility control indicated that this approach may increase survival and affect social and spatial behaviour of treated animals, although the effects are species- and context-specific. The present studies suggested that a substantial initial effort is generally required to reduce population growth if fertility control is the sole wildlife management method. However, several empirical and field studies have demonstrated that fertility control, particularly of isolated populations, can be successfully used to limit population growth and reduce human–wildlife conflicts. In parallel, there is growing recognition of the possible synergy between fertility control and disease vaccination to optimise the maintenance of herd immunity in the management of wildlife diseases. The review provides a decision tree that can be used to determine whether fertility control should be employed to resolve specific human–wildlife conflicts. These criteria encompass public consultation, considerations about animal welfare and feasibility, evaluation of population responses, costs and sustainability.
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Gupta SK, Shrestha A, Minhas V. Milestones in contraceptive vaccines development and hurdles in their application. Hum Vaccin Immunother 2013; 10:911-25. [PMID: 24262991 DOI: 10.4161/hv.27202] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Contraceptive vaccines have been proposed for controlling the growing human population and wildlife population management. Multiple targets such as gonadotropin releasing hormone (GnRH), luteinizing hormone, follicle stimulating hormone, gonadotropin receptors, sperm-specific proteins and zona pellucida glycoproteins have been exploited to develop contraceptive vaccine and their efficacy investigated and shown in various experimental animal models. Vaccines based on GnRH have found application in immuno-castration of male pigs for prevention of boar-taint. Vaccines based on zona pellucida glycoproteins have shown promising results for population management of wild horses and white-tailed deer. Phase II clinical trials in women with β-human chorionic gonadotropin (β-hCG)-based contraceptive vaccine established proof of principle that these can be developed for human application. Block in fertility by β-hCG contraceptive vaccine was reversible. Further research inputs are required to establish the safety of contraceptive vaccines, improve their immunogenicity and to develop novel vaccine delivery platforms for providing long lasting immunity.
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Affiliation(s)
- Satish Kumar Gupta
- Reproductive Cell Biology Laboratory; National Institute of Immunology; Aruna Asaf Ali Marg; New Delhi, India
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Xu WX, Bhandari B, He YP, Tang HP, Chaudhary S, Talwar P, Gupta SK, Wang J. Mapping of epitopes relevant for induction of acrosome reaction on human zona pellucida glycoprotein-4 using monoclonal antibodies. Am J Reprod Immunol 2012; 68:465-75. [PMID: 22860757 DOI: 10.1111/j.1600-0897.2012.01177.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2012] [Accepted: 06/18/2012] [Indexed: 11/29/2022] Open
Abstract
PROBLEM To decipher structural and functional aspects of human zona pellucida glycoprotein-4 (ZP4), the epitopes recognized by monoclonal antibodies (MAbs) have been mapped. METHOD OF STUDY Recombinant human ZP4-mediated induction of acrosome reaction in human sperm was studied in the absence and presence of ZP4-specific MAbs. The epitopes of MAbs were mapped using recombinant peptides expressed in Escherichia coli. RESULTS Monoclonal antibodies (MA-1662, MA-1671) against human ZP4 showed specific binding to ZP matrix of human eggs in an indirect immunofluorescence assay. Both the antibodies showed significant (P < 0.05) inhibition in the baculovirus-expressed recombinant ZP4-mediated acrosome reaction. MA-1671 recognized N-terminal fragment of ZP4 and minimal epitope mapped to amino acid residues 126-130 (PARDR), whereas MA-1662 reacted to C-terminal fragment and minimal epitope mapped to amino acid residues 256-260 (ENELV). CONCLUSIONS The epitopes corresponding to both N- and C-terminal parts of human ZP4 may be relevant for its biological activity.
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Affiliation(s)
- Wan-Xiang Xu
- Department of Reproductive Biology, Shanghai Institute of Planned Parenthood Research, Shanghai 200032, China
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Kirkpatrick JF, Lyda RO, Frank KM. Contraceptive Vaccines for Wildlife: A Review. Am J Reprod Immunol 2011; 66:40-50. [DOI: 10.1111/j.1600-0897.2011.01003.x] [Citation(s) in RCA: 94] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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Gupta SK, Gupta N, Suman P, Choudhury S, Prakash K, Gupta T, Sriraman R, Nagendrakumar S, Srinivasan V. Zona pellucida-based contraceptive vaccines for human and animal utility. J Reprod Immunol 2011; 88:240-6. [DOI: 10.1016/j.jri.2011.01.011] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2010] [Revised: 12/26/2010] [Accepted: 01/16/2011] [Indexed: 11/24/2022]
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FAGERSTONE KA, MILLER LA, KILLIAN G, YODER CA. Review of issues concerning the use of reproductive inhibitors, with particular emphasis on resolving human-wildlife conflicts in North America. Integr Zool 2010; 5:15-30. [DOI: 10.1111/j.1749-4877.2010.00185.x] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Vaccines for immunological control of fertility. Reprod Med Biol 2009; 9:61-71. [PMID: 29699331 DOI: 10.1007/s12522-009-0042-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2009] [Accepted: 11/06/2009] [Indexed: 10/20/2022] Open
Abstract
Vaccines have been proposed as one of the strategies for population control. Immunocontraceptive vaccines can be designed to inhibit: (1) production of gametes (sperm and egg); (2) functions of gametes, leading to blocking of fertilization; and (3) gamete outcome (pregnancy). Immunization with gonadotropin-releasing hormone coupled to different carriers has shown curtailment in the production of sperm with concomitant infertility in various species. Immunization of nonhuman primates and men with ovine follicle stimulating hormone has also resulted in reduced sperm output. Various spermatozoa-specific proteins such as FA1, PH-20, LDH-C4, SP-10, SP-17, sp56, SPAG9, and Izumo have been proposed as candidate antigens to develop contraceptive vaccines, which have shown efficacy in inhibiting fertility in different animal models. Immunization with zona pellucida glycoproteins-based immunogens also results in curtailment of fertility in a variety of species. However, ways to overcome the observed oophoritis associated with zona proteins immunization have yet to be discovered, a necessary step before their proposal for control of human population. Nonetheless, this is a very promising approach to control wildlife animal population. Phase II clinical trials of β-human chorionic gonadotropin-based vaccine in women have established the proof of principle that it is possible to inhibit fertility without any untoward side-effects by vaccination. Further scientific inputs are required to increase the efficacy of contraceptive vaccines and establish their safety beyond doubt, before they can become applicable for control of fertility in humans.
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Hardy CM, Beaton S, Hinds LA. Immunocontraception in mice using repeated, multi-antigen peptides: immunization with purified recombinant antigens. Mol Reprod Dev 2007; 75:126-35. [PMID: 17474093 DOI: 10.1002/mrd.20745] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Two immunocontraceptive antigens (AgE and AgF) were constructed that included different combinations of highly species-specific peptides from the mouse reproductive antigens SP56, ZP3, ZP2, and ZP1 in the form of multi-antigen peptides (MAPs). Both AgE and AgF contained three tandem repeats each of ZP2 and ZP3 peptide epitopes and a single copy of a ZP1 peptide sequence all of which had previously been demonstrated to individually have immunodominant or contraceptive effects. In addition, AgF contained a single contraceptive peptide derived from SP56, the putative ZP3 receptor protein on sperm. The antigens were expressed and affinity purified as recombinant repeated multi-antigen (polyepitope) peptides using an Escherichia coli maltose binding protein (MBP) expression system. Female BALB/c mice actively immunized with these antigens in Freund's adjuvants produced variable serum antibody responses to the component peptides. Fertility rates for animals immunized with AgE (40%) and AgF (20%) were significantly reduced compared to MBP immunized mice (90%), but the reduction in fertility did not correlate with peptide-specific serum antibody levels. Ovaries from all immunized mice appeared histologically normal with no evidence of oophoritis. These results demonstrate that high levels of immunocontraception can be achieved in mice, without apparent side-effects, using species-specific immunogens that include repeated peptides from proteins involved in fertilization.
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Childs JE, Mackenzie JS, Richt JA. Pre-spillover prevention of emerging zoonotic diseases: what are the targets and what are the tools? Curr Top Microbiol Immunol 2007; 315:389-443. [PMID: 17848073 PMCID: PMC7120954 DOI: 10.1007/978-3-540-70962-6_16] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The uneven standards of surveillance, human- or animal-based, for zoonotic diseases or pathogens maintained and transmitted by wildlife H(R)s, or even domestic species, is a global problem, readily apparent even within the United States, where investment in public health, including surveillance systems, has a long and enviable history. As of 2006, there appears to be little scientific, social, or political consensus that animal-based surveillance for zoonoses merits investment in international infrastructure, other than the fledgling efforts with avian influenza, or targeted nontraditional avenues of surveillance and research. National institutions charged with strategic planning for emerging diseases or intentional releases of zoonotic agents have emphasized improving diagnostic capabilities for detecting human infections, modifying the immune status of human or domestic animals through vaccines, producing better antiviral or antibacterial drugs, and enhancing human-based surveillance as an early warning system. With the possible exception of extensive human vaccination, each of these approaches target post-spillover events and none of these avenues of research will have the slightest impact on reducing the risk of additional emergence of viruses or other pathogens from wildlife. Novel schemes of preventing spillover of human pathogens from animal H(R)s can only spring from improving our understanding of the ecological context and biological interactions of pathogen maintenance among H(R)s. Although the benefit derived from investments to improve surveillance and knowledge of zoonotic pathogens circulating among wildlife H(R) populations is uncertain, our experience with HIV and the looming threat of pandemic avian influenza A inform us of the outcomes we can expect by relying on detection of post-spillover events among sentinel humans.
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Affiliation(s)
- James E. Childs
- Department of Epidemiology and Public Health and Center for Eco-Epidemiolog, Yale University School of Medicine, 60 College St, 208034, 06520-8034 New Haven, CT USA
| | - John S. Mackenzie
- Centre for Emerging Infectious Diseases, Australian Biosecurity Cooperative Research Centre, Curtin University of Technology, U1987, 6845 Perth, WA Australia
| | - Jürgen A. Richt
- Virus and Prion Diseases of Livestock Research Unit, National Animal Disease Center USDA, 2300 Dayton Ave Ames, 50010 IA USA
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Li H, Piao YS, Zhang ZB, Hardy CM, Hinds LA. Molecular cloning and assessment of the immunocontraceptive potential of the zona pellucida subunit 3 from Brandt's vole (Microtus brandti). Reprod Fertil Dev 2006; 18:331-8. [PMID: 16554008 DOI: 10.1071/rd05049] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2005] [Accepted: 11/01/2005] [Indexed: 11/23/2022] Open
Abstract
A full-length cDNA encoding Brandt's vole (Microtus brandti) zona pellucida glycoprotein subunit 3 (vZP3) was isolated using rapid amplification of cDNA ends-polymerase chain reaction (RACE-PCR). The cDNA contains an open reading frame of 1254 nucleotides encoding a polypeptide of 418 amino acid residues. The deduced amino acid sequence of vZP3 revealed high overall homology with hamster (82.1%), mouse (81.3%) and rat (80.6%). A synthetic vZP3 peptide corresponding to amino acid residues 328-343 was conjugated to keyhole limpet hemocyanin (KLH-vZP3(328-343)) and used to immunise female Brandt's voles in order to test the efficacy of this peptide as a contraceptive antigen. High IgG antibody levels to the vZP3(328-343) peptide were present in the sera of female voles immunised with KLH-vZP3(328-343) and these also cross-reacted to the zona pellucida in ovaries of Brandt's vole. The fertility of the KLH-vZP3(328-343) -immunised voles was reduced by 50% compared with controls without evidence of significant ovarian pathology.
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Affiliation(s)
- Hui Li
- State Key Laboratory of Reproductive Biology, The Chinese Academy of Sciences, Beijing 100080, China
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Naz RK, Gupta SK, Gupta JC, Vyas HK, Talwar AGP. Recent advances in contraceptive vaccine development: a mini-review. Hum Reprod 2005; 20:3271-83. [PMID: 16113040 DOI: 10.1093/humrep/dei256] [Citation(s) in RCA: 90] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Contraceptive vaccines (CV) may provide viable and valuable alternatives to the presently available methods of contraception. The molecules that are being explored for CV development either target gamete production [luteinizing hormone-releasing hormone (LHRH)/GnRH, FSH], gamete function [sperm antigens and oocyte zona pellucida (ZP)], and gamete outcome (HCG). CV targeting gamete production have shown varied degrees of efficacy; however, they either affect sex steroids causing impotency and/or show only a partial rather than a complete effect in inhibiting gametogenesis. However, vaccines based on LHRH/GnRH are being developed by several pharmaceutical companies as substitutes for castration of domestic pets, farm and wild animals, and for therapeutic anticancer purposes such as in prostatic hypertrophy and carcinoma. These vaccines may also find applications in clinical situations that require the inhibition of increased secretions of sex steroids, such as in uterine fibroids, polycystic ovary syndrome, endometriosis and precocious puberty. CV targeting molecules involved in gamete function such as sperm antigens and ZP proteins are exciting choices. Sperm constitute the most promising and exciting target for CV. Several sperm-specific antigens have been delineated in several laboratories and are being actively explored for CV development. Studies are focused on delineating appropriate sperm-specific epitopes, and increasing the immunogenicity (specifically in the local genital tract) and efficacy on the vaccines. Anti-sperm antibody (ASA)-mediated immunoinfertility provides a naturally occurring model to indicate how a vaccine might work in humans. Vaccines based on ZP proteins are quite efficacious in producing contraceptive effects, but may induce oophoritis, affecting sex steroids. They are being successfully tested to control feral populations of dogs, deer, horses and elephants, and populations of several species of zoo animals. The current research for human applicability is focused on delineating infertility-related epitopes (B-cell epitopes) from oophoritis-inducing epitopes (T-cell epitopes). Vaccines targeting gamete outcome primarily focus on the HCG molecule. The HCG vaccine is the first vaccine to undergo Phase I and II clinical trials in humans. Both efficacy and lack of immunopathology have been reasonably well demonstrated for this vaccine. At the present time, studies are focused on increasing the immunogenicity and efficacy of the birth control vaccine, and examining its clinical applications in various HCG-producing cancers. The present article will focus on the current status of the anti-sperm, anti-ZP, anti-LHRH/GnRH and anti-HCG vaccines.
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Affiliation(s)
- Rajesh K Naz
- Reproductive Immunology and Molecular Biology Laboratories, Department of Obstetrics and Gynecology, West Virginia University, School of Medicine, Morgantown, West Virginia 26505, USA.
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Abstract
The world's population is growing at a tremendous rate, affecting growth and development. Apart from this population growth, unintended pregnancies resulting in elective abortions continue to be a major public health issue. In over half of these unintended pregnancies, the women have used some type of contraception. Thus, there is an urgent need for a better method of contraception that is acceptable, effective and available. The contraceptive choices available to women at this time include steroid contraceptives, intrauterine devices, barrier methods, spermicides, natural family planning, male and female sterilisation, and recently available emergency contraceptives. Contraceptive vaccines (CVs) may provide viable and valuable alternatives that can fulfill most, if not all, properties of an ideal contraceptive. Since both the developed and most of the developing nations have an infrastructure for mass immunisation, the development of vaccines for contraception is an exciting proposition. The molecules that are being explored for CV development either target gamete production (gonadotropin releasing hormone, follicle-stimulating hormone and luteinising hormone), gamete function (zona pellucida [ZP] proteins and sperm antigens) or gamete outcome (human chorionic gonadotropin [hCG]). Disadvantages of CVs targeting gamete production are that they affect sex steroids and/or show only a partial effect in reducing fertility. CVs targeting gamete function are better choices. Vaccines based on ZP proteins are quite efficacious in producing contraceptive effects. However, they invariably induce oophoritis affecting sex steroids. Sperm antigens constitute the most promising and exciting targets for CVs. Several sperm-specific antigens have been delineated in several laboratories and are being actively explored for CV development. Antisperm antibody-mediated immunoinfertility provides a naturally occurring model to indicate how an antisperm vaccine will work in humans. Vaccines targeting gamete outcome primarily focus on the hCG molecule. The hCG vaccine is the first vaccine to undergo phase I and II clinical trials in humans. Both the efficacy and the lack of immunotoxicity have been reasonably well demonstrated for this vaccine. The present studies focus on increasing the immunogenicity and efficacy of this birth control vaccine.
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Affiliation(s)
- Rajesh K Naz
- Division of Research, Department of Obstetrics and Gynecology, Medical College of Ohio, Toledo, Ohio 43614-5806, USA.
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Cui X, Duckworth J. Mapping of B cell epitopes on the zona pellucida 2 protein of a marsupial, the brushtail possum (Trichosurus vulpecula). Mol Reprod Dev 2005; 70:485-93. [PMID: 15685627 DOI: 10.1002/mrd.20220] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Immunocontraceptive vaccines against zona pellucida (ZP) proteins are being developed for brushtail possum (Trichosurus vulpecula) management in New Zealand. Mapping of B cell epitopes on the ZP2 protein of possums was undertaken in this study to define the antigenic regions that may be crucial to sperm-egg binding. The amino acid sequence of the full-length possum ZP2 protein (712 amino acids) was used to synthesize a complete set of 71 (15-mer) biotinylated peptides with an offset of five amino acids. The peptides were used in a modified enzyme-linked immunosorbent assay (ELISA) to identify continuous epitopes recognized by antibodies in the sera of possums immunized with recombinant possum ZP2 (rZP2) constructs. Seventeen continuous epitopes were located on possum ZP2 protein. Comparisons of the peptide binding pattern of antibodies in individual sera with the fertility status of the same immunized possums revealed three significant infertility-relevant peptide epitopes (amino acids 111-125, 301-315, and 431-445). One of these (amino acids 431-445) bound to possum spermatozoa from the caudal epididymis. The implications of these findings for developing immunocontraceptive vaccines for possum control are discussed.
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Affiliation(s)
- Xianlan Cui
- Cooperative Research Centre for Conservation and Management of Marsupials, Landcare Research, Lincoln, Canterbury, New Zealand.
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Ferro VA. Current advances in antifertility vaccines for fertility control and noncontraceptive applications. Expert Rev Vaccines 2002; 1:443-52. [PMID: 12901582 DOI: 10.1586/14760584.1.4.443] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The search for effective antifertility vaccines has been actively pursued for decades in clinical applications as contraceptives or in the treatment of hormone-dependent conditions. More recently, innovations have seen immunocontraception being employed successfully in veterinary and farming applications, as well as in population control of a number of different wildlife species. Although the basic principle behind these vaccines is the same, design considerations and criteria for commercialization are very different. This review will examine current advances in this field and evaluate the future scope of antifertility vaccines.
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Affiliation(s)
- Valerie A Ferro
- Department of Immunology, University of Strathclyde, Glasgow, UK.
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