Characterization of sperm agglutinins in sera from infertile women.

Sperm agglutinins detectable by a tray agglutination technique in sera from women from infertile couples were characterized. Preparative zone electrophoresis of seven head-to-head-agglutinating sera revealed two patterns. In two sera sperm agglutinins were obtained in the gamma-globulin fraction, whereas in five sera the agglutinating activity was detected in the beta-globulin fraction only. By immunoaffinity chromatography, IgM and IgG sperm antibodies were demonstrated in the former two sera and also in two tail-to-tail-agglutinating sera. The beta"sperm agglutinin was not found to share physicochemical or immunological characteristics with beta-lipoprotein in the present investigation by ultracentrifugation, by precipitation of beta-lipoprotein with heparin and MnCl2, by absorption of beta-lipoprotein with colloidal silic acid, or by affinity chromatography on an anti-beta-lipoprotein column. An apparent neutralizing effect of anti-beta-lipoprotein by simple addition of antiserum to sera containing the beta-sperm agglutinin was shown to be due to a reaction with sperm components released from the spermatozoa by which the antiserum had been absorbed before use. These sperm components were found to neutralize the activity of the beta-sperm agglutinin only, whereas no effect was observed in sera containing sperm antibodies. By Sephadex G-200 fractionation the beta-sperm agglutinin was shown to have a high molecular weight (MW greater than or equal to 600,000). Ultrafiltration and dialysis experiments gave no evidence of involvement of low-molecular compounds in head-to-head agglutination.