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At least 19 recordsLinked to original sources
PubMed1979

[Status and developmental trends of immunologic contraceptive technics].

The development of contraceptive vaccines is matter of international research. Among antigens possible unique to the reproductive process, sperm antigens, antigens of seminal plasma and of the ovum, antigens of placental hormones and of placenta specific proteins appear suitable targets of the production of fertility regulating vaccines. High specifity of these vaccines can prevent cross reaction with other body cells.

Animals↗
PubMed1992

[Immunological contraception--future possibilities in family planning].

In principle, immunological contraception is primarily a question of producing antibodies to block or inactivate a vital functional process. The antibodies can be used to elicit the corresponding antigen which, more or less modified, may then be used as a vaccination immunogen. The antibodies may also serve as the starting point in the production of new (antiidiotypic) antibodies, which have a certain potential function as a vaccine, owing to their antigenic capacity to stimulate the formation of functionally active antibodies. In addition to their use in developing a method of contraceptive vaccination (active immunisation), functional antibodies can also be used in passive immunisation. Such treatment during early gestation would result in abortion, and might be an alternative means of terminating pregnancy. In such cases, the antibodies might be combined with a toxin, yielding an immunotoxin exerting highly specific effects on the conceptus.

Antibodies↗
PubMed1987

Recent developments in immunocontraception.

The possibility of controlling fertility by antibodies inactivating key reproductive hormones has been amply demonstrated by active and passive immunization in primates. Four birth control vaccines directed against human chorionic gonadotropin are currently in early clinical trials. The nature of these vaccines and the underlying principles are described, as are the available results from clinical studies. The alpha- and beta-subunits of human chorionic gonadotropin and the ovine gonadotropins have been cloned by recombinant deoxyribonucleic acid methods. A new breed of vaccines that combines the genes of gonadotropins linked to hepatitis B surface protein has been developed. The next generation of birth control vaccines is likely to be polyvalent and to have the ability to intercept fertility at more than one point. A number of monoclonal antibodies against human sperm have shown the presence of tissue-specific antigens and the possibility of preventing the fertilization of the egg. Inclusion of more than one carrier in the vaccine increases the percentage of high responders and accords immunoprophylactic benefits against more than one disease. Conjugates have also been developed to obtain high titers of antibodies against gonadotropin-releasing hormone with permissible adjuvants. This vaccine may have therapeutic applications in hormone-dependent cancers and precocious puberty.

Chorionic Gonadotropin↗
PubMed1978

The present and future of immunologic approaches to contraception.

A vaccine capable of causing active immunity against one or more key elements of conception would have several advantages over currently available methods of fertility regulation. It would be amenable to mass use, would require only periodic follow-up, and would not require continuous user motivation. Although natural infertility attributable to immunologic factors has been amply documented, the natural mechanism has been only partially delineated. Consequently, researchers trying to develop a workable vaccine are taking various approaches. This report includes a discussion of autoimmune aspermatogenesis, anti-zona pellucida, anti-nonhormonal placenta-specific protein vaccines, and immunization against female and/or early embryonic antigens, including current approaches to the development of an anti-human chorionic gonadotrophin (HCG) vaccine. The potential advantages and disadvantages of the various immunologic methods are discussed, and the author concludes that although the problems associated with present methods of immunologic contraception are substantial they can be resolved.

Animals↗
PubMed1992

Vaccines for control of fertility and hormone dependent cancers.

Two vaccines, namely one inducing antibodies against hCG and the other against GnRH, are now in clinical trials. The hCG vaccine has entered Phase II clinical trials in three centres in India after successfully completing Phase I clinical studies in several centres in India and in four countries abroad. The vaccine was found to be devoid of side-effects; its effect was reversible. The available data on 179 cycles indicate that the vaccine prevents pregnancy at antibody titres above 50 ng/ml. A genetically engineered version of the vaccine has also been approved for trials in human lung cancer patients of the type which make hCG. hCG is observed to be a growth factor for such tumours. The GnRH vaccine is usable in both males and females as the deca-peptide is common to both sexes. Following suitable experimental and toxicology studies, the vaccine is currently in Phase I/Phase II clinical trials in patients of prostate carcinoma. Where antibody GnRH antibodies were induced, the LH, FSH and testosterone levels declined. This was accompanied by a reduction in prostate specific antigen. Clinical improvement was observed in many cases. The vaccine has also entered Phase I clinical studies in postpartum women, with the objective to extend the lactational amenorrhoea and extend inter-child interval.

Chorionic Gonadotropin↗
PubMed1989

Immunological approaches to contraception in dogs.

The demand for safe, effective and cost-efficient means of pet population control has generated interest in the development of alternatives to surgical gonadectomy. The purpose of this review is to discuss the potential of immunological approaches to fertility control and to outline recent developments that may aid their design. Among the most promising candidates for immunoneutralization is gonadotrophin releasing hormone (GnRH). We have developed a reliable and reproducible GnRH-protein conjugate antigen and demonstrated that immunologically induced infertility is possible in dogs.

Adjuvants, Immunologic↗
PubMed1975

[Antigens of the human placenta (author's transl)].

The immunologic relations between mother, foetus and placenta are discussed and those antigens of the human placenta already characterized by their physico-chemical and immunochemical properties described. In diagnostics the detection and determination of placental proteins is used in pregnancy tests, for the evaluation of placental functions and the detection of malignant diseases. Antibodies to placental antigens have an abortive effect; immunization against placental specific proteins may have implications as an immunologic contraceptive method and for the immunotherapy of choriocarcinoma.

Abortion, Spontaneous↗
PubMed1992

Anti-trophectoderm vaccines: rationale and methods used for antigen identification and selection.

Trophoblast, forming a continuous interface at the maternal-fetal junction, is of considerable interest to biologists. An area of recent research is the search for trophoblast-specific antigens. It is believed that identification and characterization of these antigens may have many practical applications such as in development of contragestational vaccines. To be acceptable for humans such a vaccine will need to be effective before the completion of implantation and appearance of the primitive streak about 14 days after fertilization. This will not alter the menstrual cycle or the time of menses. Vaccines having a later effect resulting in termination of pregnancy after this time would be considered abortifacients. Although logistical and ethical considerations necessitated the use of post-implantation human trophoblast in WHO Birth Control Vaccine studies, the antigens isolated from such tissues would need to be expressed and be detectable on the surface of pre-implantation trophectoderm if they are to represent appropriate candidates for vaccine development. The criteria for identification and selection of these antigens will be reviewed.

Animals↗
PubMed1992

Anti-hCG vaccines are in clinical trials.

Two vaccines inducing antibodies against human chorionic gonadotropin (hCG) have completed Phase I clinical trials, indicating the reversibility and safety of these vaccines. One is currently in Phase II efficacy trials in women in three major centres in India. The available data suggest that the vaccine prevents pregnancy above antibody titres of 50 ng/ml hCG bioneutralization capacity.

Antibodies↗