Use of specific monoclonal antibodies to secretory IgA for the detection of spermatozoal antibodies in serum and seminal plasma by enzyme-linked immunosorbent assay

Secretory monoclonal IgA antibody to human sperm produced by gastrointestinal immunization inhibits human sperm activity and mouse in vitro fertilization

BALB/c mice were immunized intragastrically with human sperm. Cells from the Peyer's patches and spleens of the immunized mice were for the preparation of hybridomas secreting antisperm monoclonal IgA (mcIgA). The specific ratio of IgA-secreting cells in Peyer's patches was much higher than that in spleen. The binding site on human sperm of 9 of 19 mcIgA was in the post-acrosomal region using an immunofluorescent assay. Two of eight selected mcIgA caused strong human sperm agglutination and three of them produced significant inhibition of mouse in vitro fertilization. No mcIgA tested caused obvious human sperm immobilization or inhibited mouse in vivo fertilization. In vitro assembly of selected mcIgA in ascites with mouse secretory component (SC) caused no significant changes in effects on sperm function and in vitro fertilization. By use of Western blotting, dimer or higher polymers were demonstrated in all selected mcIgAs and corresponding protein antigens in 6 of 8 selected mcIgAs. These results suggest that human sperm function may be inhibited and fertilization rate reduced by specific secretory IgA to human sperm and that secretory immunity to protein antigens of human sperm could be induced by intragastrointestinal immunization.

Analysis of human sperm membrane antigens reacting with sera from antisperm antibody positive and negative patients by western blotting

Immunological infertility is thought to be caused by the binding of antibodies to 'fertility-related' antigen(s) on the sperm membrane. We compared antibody profiles in sera from 20 ASA(+) and ASA(-) men, using a sperm membrane extract as an antigen. Antigens were separated by SDS-PAGE under reducing conditions. The patients were classed as ASA(+) by the MAR (> 50%), d-IBT (> 20%) and TAT (> 1:64). The results showed that immunoreactive bands in both the ASA(+) and ASA(-) groups were heterogeneous and included bands covering the whole molecular weight range. Statistical analysis showed significantly more patients in the ASA(+) group having immunoreactive bands at molecular weights of 32 Kd (P = 0.006) and 79 Kd (P = 0.02) when compared to the ASA(-) group. In the ASA(-) group significantly more patients had reactive bands at 81 Kd (P = 0.01) when compared to the ASA(+) group. The 32 Kd antigen reacted only with sera from ASA(+) patients. We conclude that differences exist between the ASA(+) and ASA(-) groups when this extraction method is used and that the isolation and purification of the 32 Kd protein may justify further investigation.