Premium
Antisperm Antibody Binding to Human Sperm Inhibits Capacitation Induced Changes in the Levels of Plasma Membrane Sterols
Author(s) -
BENOFF SUSAN,
COOPER GEORGE W.,
HURLEY IAN,
MANDEL FRANCINE S.,
ROSENFELD DAVID L.
Publication year - 1993
Publication title -
american journal of reproductive immunology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.071
H-Index - 97
eISSN - 1600-0897
pISSN - 1046-7408
DOI - 10.1111/j.1600-0897.1993.tb00612.x
Subject(s) - sperm , capacitation , filipin , biology , cholesterol , antiserum , endocrinology , antibody , medicine , membrane fluidity , andrology , membrane , chemistry , biochemistry , immunology , genetics
PROBLEM: Human spermatozoa express mannose ligand receptors (MLRs) over the entire head when incubated under conditions that promote loss of free cholesterol. Binding of IgA, IgG. and/or IgM head‐directed anti‐sperm antibodies (ASAs) to freshly isolated sperm blocks MLR expression in a dose dependent manner. METHODS: Comparison of Western blots of immunoprecipated glycoproteins from fresh sperm exposed to ASAs from women with those of sperm membrane proteins isolated from capacitated sperm probed with a goat anti‐human macrophage MLR antiserum showed that ASAs do not react with human sperm MLRs of 48 and 61 kd apparent molecular weight. RESULTS: The direct effect of ASA binding was to increase membrane free cholesterol content which remained greater than 0.005 μmol/10 9 sperm after 18 h incubations, whereas the sterol content of controls decreased to less than 0.001 μmol/10 9 sperm. Cholesterol addition to sperm inhibited MLR expression in a manner analogous to ASA binding, while increasing temperatures up to the crystalline/liquid‐crystalline phase transition for sperm membranes; less than 45°C failed to promote the appearance of MLRs on the surface of fresh sperm. CONCLUSIONS: We conclude that ASA effects on membrane cholesterol content prevent the membrane fluidity changes needed for MLR expression.