Reactions of antisera to HCG with living human spermatozoa.

Antisera to hCG were incubated with living human spermatozoa. Agglutination and complement-dependent immobilization of the spermatozoa occurred with the anti-hCG sera but not with control sera. The antisera also reacted with human blood cells. The anti-sperm activities were largely removed by absorbing the sera with human blood cells, although these absorptions had no apparent effect on the anti-hCG activities measured by passive haemagglutination. There was, therefore, little evidence for the presence of hCG-like molecules at the surface of living human spermatozoa.