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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↗
PubMedDate not supplied

Monoclonal sperm antibodies: their potential for investigation of sperms as target of immunological contraception.

We generated 149 hybridoma cell lines secreting antibodies against human spermatozoal antigens of which antibodies from 136 hybridoma lines also reacted with seminal plasma constituents. The occurrence of common antigeneic determinants on spermatozoa and seminal plasma was further demonstrated by competitive inhibition ELISA tests. We found that seven hybridoma clones secreted antibodies reactive with spermatozoa but nonreactive with seminal plasma. Antibodies from 5 clones were sperm-agglutinating and from 15 clones sperm-immobilizing. Localization of sperm antigens reactive with the monoclonal antibodies was demonstrated by indirect immunoperoxidase staining. A synthetic decapeptide, earlier shown to be reactive with naturally occurring human iso- and autosperm antibodies, was shown to be reactive with the monoclonal antibody VII-5 in ELISA tests.

Agglutination↗
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↗
PubMed1994

The suitability of human chorionic gonadotropin (hCG)-based birth-control vaccines.

It has been widely hoped that immunological methods of fertility regulation by active immunization against specific antigens of the oocyte, sperm, zygote and early embryo, and the placental pregnancy hormone human chorionic gonadotropin (hCG), will provide a means to control the problem of worldwide population growth. The most advanced candidate vaccines are based on hCG immunogens and have entered clinical trials. However, during the past few years, increasing evidence has emerged that the current approaches using hCG as the target molecule may have some major drawbacks. On the basis of their recent findings, Stephan Dirnhofer and colleagues raise doubts on the suitability, safety and efficacy of gonadotropin-based immunological contraceptive vaccines.

Chorionic Gonadotropin↗
PubMed1982

[Current status of the development of interceptive agents].

An account is given of present applications of interceptively acting substances. Pharmaceuticals used so far for postcoital conception (oestrogens, gestagens, and combinations of these) are suitable for single application, but their regular use is limited by side-effects. Various approaches are being taken to the development of effective interceptives for high-continuity application but with low side-effects. Antigestagens, LHRH-analogues, and immunological contraceptives seem to be among the most promising classes of substances for the above purpose. Yet, none of these substances has been developed as yet to the level of clinical applicability.

Animals↗
PubMed1986

Control of fertilization by immunization with peptide fragments of sperm specific LDH-C4.

The use of a well-defined, synthetic antigen is essential to progress in developing a vaccine for fertility control and to establish with certainty the utility of such technology. The studies with LDH-C4 are consistent with the feasibility of using a synthetic antigen in a vaccine to control fertility. LDH-C4 remains the best-developed candidate for future studies. Immunization with LDH-C4 does suppress fertility, and the complete biochemical characterization of this isozyme is well underway. These studies will provide a wealth of synthetic antigens to substitute for the natural product in experiments to determine whether immunologic contraception is appropriate and desirable for wide-scale application in human beings.

Animals↗
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↗
PubMedDate not supplied

Application of monoclonal antibodies for antigen mapping of male and female generative tissue.

With the single experiment of nature hindering the rejection of the fetus in the mother, new basic mechanisms of this immunological phenomenon can be studied. The technique of monoclonal antibodies provides a helpful tool for the study of membrane structural and cytoplasmic molecules. Hybridoma clones offer for the first time the possibility of obtaining unlimited amounts of almost pure antibodies or very high titers and of defined characteristics. The most common application with reproductive tract monoclonals are found as follows: 1) Immuno-assays; 2) Immuno-diagnostics; 3) Imaging of tumors; 4) Immuno-therapy; 5) Induction of anti-idio-types; 6) Fertility control; 7) Application in basic studies and mechanisms. The following interesting results were obtained in this area: 1) The biological role of hormones can be critically analysed by the use of highly specific non-cross-reactive monoclonal antibodies. 2) A synthetic decapeptide earlier shown by our group to be reactive with naturally occurring human iso and autosperm antibodies demonstrated to be reactive with the monoclonal antibodies Ki VII-5 presenting potentials for an investigation of sperm as target of immunological contraception for possible diagnostic and therapeutic use in immunologic infertility. 3) A specific post fertilization-development influencing antigen was identified by Menge using monoclonal antibodies. 4) Five hybridoma clones producing monoclonals to porcine zona pellucida were established, and showed a characteristic staining pattern of oocytes from human eggs, hamsters, rabbits and mice by immunofluorescence.

Abortifacient Agents, Nonsteroidal↗
PubMed1982

Fertility following discontinuation of different methods of fertility control.

The possibility of permanent sterility following use of modern contraceptive agents is a concept which causes great concern amongst members of the lay public. However, a thorough review of the literature gives a great deal of reassurance on this topic. The combined oral contraceptive pill causes slight delay, and the injectable contraceptives a moderate delay in the return of fertility following discontinuation, but there is no evidence of a greater likelihood of permanent infertility than in the normal population. The progestogen-only minipill should be risk-free, but final data are lacking. Epidemiological studies do not indicate an increased risk of infertility following IUD use, but it seems likely that there must be a very small number of IUD users who develop permanent infective damage to the Fallopian tubes. Barrier methods and periodic abstinence probably do not have any significant effect on subsequent fertility. Barrier methods could be protective. Therapeutic abortion may have a small deleterious effect on long-term reproductive success, but the data are inconclusive. Detailed information on fertility following use of other methods is not available.

Abortion, Induced↗
PubMed1994

The value and use of different contraceptive methods.

Reductions in the rates of maternal and child mortality as well as in demographic growth are directly linked to contraceptive usage. The development and availability of safer, improved contraceptives which are convenient to use could be expected to be used by a larger group of individuals and thus make an impact on reproductive health as well as on population growth rates. Such arguments have been used to support contraceptive research. This article deals with some of the developments that have occurred as a consequence of such efforts.

Contraception↗
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↗