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At least 37 records · Page 2Linked to original sources
PubMed2004

Fertilin beta peptidic liposomes inhibit fertilization by steric blockage.

Liposomes presenting fertilinbeta peptides are inhibitors of mouse in vitro fertilization. We undertook a study of the relationship between IC(50) and mole fraction of fertilinbeta in the liposome, and the size dependence of inhibition of fertilization to understand the mechanism of their inhibition. Our results indicate that a small number of multivalent contacts are required for efficient attachment of inhibitor to receptor on the target membrane, and that, as designed, the liposomes target the egg membrane but not the sperm membrane. The size dependence of the liposome inhibition demonstrates that the liposomes physically block access of the sperm to the egg membrane thereby preventing sperm binding to all egg receptors not just the fertilinbeta receptor.

ADAM Proteins↗
PubMed1998

A combinatorial phage display library for the generation of specific Fab fragments recognizing human spermatozoa and inhibiting fertilizing capacity in vitro.

To select a source of lymphocytes for the generation of an anti-sperm-biased combinatorial phage display library, venous blood was obtained from 34 vasovasostomy (vasectomy reversal) patients approximately 3 mo after surgery. Using a variety of immunoassays, serum was analyzed for antibodies against human spermatozoa, and a patient was selected on the basis of high titer of antibodies that recognized the equatorial region of the sperm head and inhibited sperm fertilizing capacity in vitro. Total RNA isolated from the stored lymphocytes of this individual was reversed transcribed, and gamma1 (Fd) region and kappa chains were amplified by polymerase chain reaction for the successful construction of an antibody phage display library. The library was panned against human spermatozoa to isolate sperm-specific phage that recognized the equatorial region of the sperm head. Three preparations of Fab were tested via the hamster egg penetration test. Each preparation significantly (p < 0. 005) inhibited sperm-egg binding and fusion, with one preparation (designated Fab-G) causing complete inhibition. Sequence analysis of the kappa light gene encoding Fab-G revealed a 93% homology with the light chain of human anti-human immunodeficiency virus gp120 p35 variable region. This technology may have a practical application in characterization of the immune response to spermatozoa and for the design of sperm-based contraceptive vaccines.

Amino Acid Sequence↗
PubMed1984

Monoclonal antibody to a human germ cell membrane glycoprotein that inhibits fertilization.

A monoclonal antibody to an antigen in the human germ cell membrane did not agglutinate or immobilize sperm but inhibited binding and penetration of zona-free hamster ova by human sperm and blocked murine fertilization in vitro. The antibody, of the 2a subclass of immunoglobulin G, was germ cell-specific but not species-specific. It recognized a single antigen of 23 kilodaltons that has been isolated from human germ cells. This fertilization antigen, located on the postacrosome , midpiece, and tail of human sperm, is a glycoprotein of testicular origin associated with some types of human involuntary immunoinfertility .

Animals↗
PubMed1964

INSECT FERTILITY: INHIBITION BY FOLIC ACID DERIVATIVES.

Folic acid antagonists inhibited oviposition by screw-worm flies [Cochliomyia hominivorax (Coquerel); Diptera: Calliphoridae]. Fertility was unaltered when sufficient folic acid was administered simultaneously, or it was partly restored spontaneously about 2 weeks after treatment. Folic acid antagonists principally affected only maturing eggs at any age, rather than those already matured.

Aminopterin↗
PubMed1993

Human follicular fluid from pre-ovulatory follicles in patients undergoing in-vitro fertilization inhibits the in-vitro growth of gram-positive micro-organisms.

In this study, we assessed the antibacterial activity of human follicular fluid obtained from patients undergoing oocyte aspiration for in-vitro fertilization and embryo transfer. Gram-positive and Gram-negative microorganisms and Candida albicans were added to the follicular fluid and broth cultures which served as controls. Follicular fluid was shown to be inhibitory against Gram-positive microorganisms; this inhibition was probably due to lysosyme and progesterone. Growth of Gram-negative micro-organisms and C. albicans were, however, supported by follicular fluid incubation.

Candida albicans↗
PubMed2006

Multivalent fertilinbeta oligopeptides: the dependence of fertilization inhibition on length and density.

The sperm protein fertilinbeta, a member of the ADAM family of proteins, is implicated in sperm-egg binding in all mammals studied to date. Multivalent inhibitors containing the three amino acid binding sequence of fertilinbeta, ECD, have been shown previously to be more effective inhibitors of fertilization than their monovalent counterparts. Here, we probed sperm-egg interactions with ruthenium-catalyzed ring-opening metathesis polymers that contained from 3 to 70 ECD pharmacophores in densities ranging from 10% to 100%. Evaluation of the polymer potencies, and synthesis of a triblock copolymer from two building blocks, revealed that two multivalent contacts are sufficient for maximal inhibition, and that the distance between ECD pharmacophores required is 7-9 monomers spanning 4-5 nm. We conclude that inhibition requires recruitment of two receptors on the egg surface into an inhibitory complex.

ADAM Proteins↗
PubMed1995

Potential contraceptive use of epididymal proteins: evidence for the participation of specific antibodies against rat epididymal protein DE in male and female fertility inhibition.

Previous studies in our laboratory indicated that immunization of male and female Wistar and Lewis rats with epididymal protein DE, resulted in the development of anti-DE antibodies in over 90% of the animals, with a significant and reversible reduction of fertility. In the present study, ELISA assays performed to analyze the evolution of the immune response indicated that antibody levels in the sera of immunized animals reached a maximum at 8 weeks after the initial injection and then gradually decreased, returning to control values by the end of the sixth month. Western blot experiments demonstrated that the immune sera specifically recognized DE in epididymal sperm extracts and epididymal cytosol, while no reaction was observed with different reproductive and essential organs. The immune sera were also capable of recognizing DE on the surface of both fresh and capacitated sperm as indicated by indirect immunofluorescence experiments. Finally, the exposure of sperm to immune sera prior to uterine insemination resulted in a significant (P < 0.05) reduction in the percentage of fertilized eggs compared to controls, with no effect on sperm motility and viability, nor on their ability to undergo capacitation. Together, these results support the participation of the raised antibodies as mediators of the antifertility effect and suggest a specific interference at the sperm-egg interaction level.

Animals↗