Effects of a Recombinant Gonadotropin-Releasing Hormone Vaccine on Reproductive Function in Adult Male ICR Mice

Gonadotropin-releasing hormone (GnRH) regulates the reproductive endocrine system in mammals. The GnRH immunocontraception vaccine can aid animal population control and management. We evaluated a recombinant GnRH fusion protein with the adjuvant MONTANIDE ISA 206 VG as a GnRH vaccine in adult male ICR mice by evaluating anti-GnRH antibodies; concentrations of follicle-stimulating hormone (FSH), luteinizing hormone (LH), and testosterone; testis size and histomorphology; and semen quality. Response was assessed after intramuscular administration of the vaccine to mice in weeks 0, 4, and 8. The vaccine induced specific antibody response by week 5, with peak of antibody levels observed by week 13 and a declining level thereafter until the end of the study at week 24. Furthermore, it reduced serum FSH, LH, and testosterone concentrations. The vaccinated mice exhibited testicular atrophy and reduced sperm quality, concentration, morphology, and viability compared to control males. The outcomes of pairings of treated males with untreated females revealed reduced mating, pregnancy rates and number of litters compared to control pairings. Assessment of this GnRH vaccine in different species could assist its development for future applications.

Latheef S, Sharun K, Khurana SK, K. A, Tiwari R, Bhatt P, K. V, Chaicumpa W. Role of Antisperm Antibodies in Infertility, Pregnancy, and Potential forContraceptive and Antifertility Vaccine Designs: Research Progress and Pioneering Vision

Sperm of humans, non-human primates, and other mammalian subjects is considered to be antigenic. The effect of changes in autoimmunity on reproductive cells such as spermatozoa and oocytes play a critical but indistinct role in fertility. Antisperm antibodies (ASAs) are invariably present in both females and males. However, the degree of ASA occurrence may vary according to individual and gender. Although the extent of infertility due to ASAs alone is yet to be determined, it has been found in almost 9-12% of patients who are infertile due to different causes. Postcoital presence of spermatozoa in the reproductive tract of women is not a contributory factor in ASA generation. However, ASA generation may be induced by trauma to the vaginal mucosa, or by anal or oral sex resulting in the deposition of sperm inside the digestive tract. It is strongly believed that, in humans and other species, at least some antibodies may bind to sperm antigens, causing infertility. This form of infertility is termed as immunological infertility, which may be accompanied by impairment of fertility, even in individuals with normozoospermia. Researchers target ASAs for two major reasons: (i) to elucidate the association between ASAs and infertility, the reason ASAs causes infertility, and the mechanism underlying ASA-mediated infertility; and (ii) to assess the potential of ASAs as a contraceptive in humans in case ASAs influences infertility. Therefore, this review explores the potential application of ASAs in the development of anti-spermatozoa vaccines for contraceptive purposes. The usefulness of ASAs for diagnosing obstructive azoospermia, salpingitis, and oligoasthenoteratozoospermia has been reviewed extensively. Important patents pertaining to potential candidates for spermatozoa-derived vaccines that may be utilized as contraceptives are discussed in depth. Antifertility vaccines, as well as treatments for ASA-related infertility, are also highlighted. This review will address many unresolved issues regarding mechanisms involving ASAs in the diagnosis, as well as prognoses, of male infertility. More documented scientific reports are cited to support the mechanisms underlying the potential role of ASA in infertility. The usefulness of sperm antigens or ASAs (recombinant) in human and wild or captive animal contraceptive vaccines has been revealed through research but is yet to be validated via clinical testing.

The continuing search for an addiction vaccine

Inspired by advances in immunology, in the 1970s scientists began to study the possibilities of mobilizing the human immune system against intruders other than pathogenic viruses and bacteria. In 1972 the suggestion was first made that it might be possible to provoke immunity to narcotic dependence. Because molecules of narcotics such as heroin and cocaine are too small to stimulate an immune response, researchers sought ways of coupling them to immunogenic proteins. The substances they developed soon became known as addiction vaccines. However, despite fifty years of research, and despite the growing problem of addiction, no vaccine against heroin, cocaine, methamphetamine or nicotine addiction has yet been licensed for clinical use. This paper reviews the history of addiction vaccinology, seeks to explain the unique appeal of a vaccinological approach to addiction, and argues for broad discussion of how such vaccines should ultimately be used.

Immunocontraception for Animals: Current Status and Future Perspective

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.

Vaccine for human contraception targeting sperm Izumo protein and YLP12 dodecamer peptide

There is an urgent need to develop a better method of contraception which is non-steroidal and reversible to control world population explosion and unintended pregnancies. Contraceptive vaccines (CV), especially targeting sperm-specific proteins, can provide an ideal contraceptive modality. Sperm-specific proteins can induce an immune response in women as well as men, thus can be used for CV development in both sexes. In this article, we will review two sperm-specific proteins, namely Izumo protein and YLP12 dodecamer peptide. Gene-knockout studies indicate that Izumo protein is essential for sperm-egg membrane fusion. Vaccination with Izumo protein or its cDNA causes a significant reduction in fertility of female mice. The antibodies to human Izumo inhibit human sperm penetration assay. Recently, our laboratory found that a significant percentage of infertile women have antibodies to Izumo protein. The second sperm-specific protein is YLP12 , a peptide mimetic sequence present on human sperm involved in recognition and binding to the human oocyte zona pellucida. Vaccination with YLP12 or its cDNA causes long-term, reversible contraception, without side effects, in female mice. Infertile, but not fertile, men and women have antibodies to YLP12 peptide. Our laboratory has isolated, cloned, and sequenced cDNA encoding human single chain variable fragment (scFv) antibody from infertile men which reacts with YLP12 peptide. The human YLP12 scFv antibody may provide a novel passive immunocontraceptive, the first of its kind. In conclusion, sperm-specific Izumo protein and YLP12 peptide can provide exciting candidates for antisperm CV development.