PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “Contraception, Immunologic”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 55 records · Page 3Linked to original sources
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↗
PubMed1986

The development of a contraceptive vaccine by purification of antigens from gametes.

There are several ways to make immunological contraceptive vaccines. We are trying to purify gamete antigens from human seminal plasma and porcine zona pellucida (ZP) by using several monoclonal antibodies (Mabs) for this purpose. A human seminal antigen relevant to sperm immobilization with corresponding antibody was purified by immunoaffinity chromatography-bound Mab 1C4. This antigen was common to human milk protein but is different from lactoferrin. It was termed "ferrisplan" and was secreted mainly from the epithelial cells of seminal vesicle and adhered to the midpiece and postnuclear cap region of spermatozoa. Another Mab 2C6 reacted only to the SP component but not to other organ extract including human milk protein. The corresponding antigen to Mab 2C6 is aimed to purify by using high performance liquid chromatography and immunoaffinity chromatography-bound Mab 2C6. Several Mabs to porcine ZP antigens common to human ZP did not block human in vitro fertilization unless the second antibody (anti-mouse gamma-globulin) was used. It is speculated that porcine ZP will not contain the antigenic component that relates to sperm receptor of human ZP. Therefore, an antigenic molecule located close to sperm receptor of human ZP must be purified from the porcine ZP by using immunoaffinity chromatography-bound Mab and other biochemical methods, expecting production of a corresponding antibody that blocks the fertilization in humans.

Animals↗
PubMed1999

Mapping of dominant B-cell epitopes of a human zona pellucida protein (ZP1).

Zona pellucida (ZP) glycoproteins contain numerous antigenic determinants including carbohydrate, protein, and conformational epitopes; and the immunogenicity of these complex glycoproteins varies in different mammalian hosts. Studies have now shown that antibodies from primates immunized with a cDNA-expressed recombinant rabbit ZP protein (the homologue of the human ZP1 [hZP1]) inhibit sperm binding to the ZP without altering ovarian function, unlike immunization with ZP3 and ZP2 protein families. The ZP1 protein or peptides derived from it (recombinant or synthetic) are therefore primary candidates for use in designing safe and reversible human and animal contraceptive vaccines. In order to define peptide epitope(s) that may be critical for eliciting an immune response sufficient to effect immunological contraception without causing any adverse effects on ovarian physiology, studies have been carried out to identify immunodominant B-cell epitopes of the ZP1 protein. The amino acid sequence of the hZP1 was used to design a set of 94 (15-mer) biotinylated peptides having an overlap of 9 amino acids. Using these peptides in a modified enzyme-linked immunoassay, antibodies in sera from rabbits or baboons immunized with native porcine ZP protein were screened for ZP1 peptide recognition. These studies demonstrate that there are a limited number of peptides recognized by primate antibodies but that the overlapping peptides sharing the sequence GPLTLELQI are recognized by both rabbit and baboon antibodies regardless of the adjuvant system used to induce the immune response. This peptide is 100% conserved in amino acid sequence between the human and pig, although the rabbit protein has two conserved amino acid substitutions (100% similar, 77% identical). Because this peptide is immunogenic as well as antigenic in primates, it could play a major role in the development of human contraceptive vaccines.

Amino Acid Sequence↗
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↗
PubMed2002

[Study on the male contraceptive based on epididymis].

More and more study on the epididymal function and sperm maturation has shown that epididymis will be one of the best target organs of male contraception, although at present there is not a male contraceptive medicine based on epididymis for clinical practice. The promoting research aspects in epididymal contraception in animal included affecting directly epididymis (such as Sulpasalazine), interfering energy metabolism and sperm mobility (such as Chlorinated Glycerol), altering the internal environment of epididymis (such as copper particles and TW19). The epididymal specific proteins could bring out some new target antigens for immunological contraception, to produce contraceptive vaccine. Some special genes, which expressed distinctively in epididymis such as SC342, bin1, have been cloned and studied on their function. These works would be helpful not only for clinical diagnosis and treatment of epididymitis and male infertility, but also for male contraceptive research and progress.

Contraception↗
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↗
PubMed1985

Effect of early postpartum use of the contraceptive implants, NORPLANT, on the serum levels of immunoglobulins of the mothers and their breastfed infants.

Ten breastfeeding women had the contraceptive implants NORPLANT inserted between days 30 and 39 postpartum. The immunoglobulins IgG, IgM and IgA were measured in the serum of the mothers and the infants before insertion and five months later. A control group of breastfeeding mothers who did not use any contraception or used local barrier methods were similarly studied. Although there were changes in the immunoglobulin levels with time in both mothers and infants, there were no group differences; this indicates that the use of NORPLANT does not influence these factors of humoral immunity.

Adult↗
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↗
PubMed1996

Identification and selective destruction of shared epitopes in human chorionic gonadotropin beta subunit.

The feasibility of producing epitope-specific antigens by mutation of the gene is demonstrated, the aim being to eliminate unwanted surface epitopes yet allowing the natural folding of the protein to maintain the desired epitope(s). The model protein is the beta subunit of human chorionic gonadotropin (hCG beta) which previously has been used as an immunological contraceptive vaccine but has extensive cross-reaction with human luteinizing hormone. Of a series of mutants made, the mutant with substitutions of Glu for Arg 68, Ser for Arg 74, His for Gly 75 and His for Val 79, lost the ability to react with a panel of cross-reacting monoclonal antibodies while retaining the discontinuous and linear epitopes specific to the holo-hormone. In addition, allocation of amino acid residues to established epitope clusters could be made: residues 24, 25, 68 and 71 probably contribute to the cluster termed beta 3, residues 20, 21, 22, 75 and 77 to cluster beta 6 and residue 68 to clusters beta 2, beta 4 and beta 5.

Chorionic Gonadotropin, beta Subunit, Human↗
PubMed1990

Partial purification of a boar sperm membrane protein inducing sperm agglutinating antibody.

For the development of immunological contraception, attention is being concentrated on the possibility of using a sperm membrane antigen. Boar sperm membrane was extracted with triton-X 100 and fractionated by Sephadex G-150 column chromatography. The glycosylated and nonglycosylated portions of protein peaks from the gel filtration were obtained by fractionating on concanavalin A-Sepharose and eluting the bound protein with 0.3 M methyl mannoside. A glycosylated fraction was found to induce sperm agglutinating antibodies in rabbit. The partially purified protein has a molecular weight of 30 kilodaltons, as determined by sodium dodecyl polyacrylamide gel electrophoresis. Further work is planned on the histochemical determination of the origin of this protein and species cross-activity of the antibody.

Animals↗