Immunodetection of a human chorionic gonadotropin-like substance in human sperm

The presence of a human chorionic gonadotropin (hCG)-like substance in human spermatozoa is reported. A highly sensitive immunocytochemical procedure was utilized (double-antibody immunofluorescence technique). Rabbit anti-hCG or rabbit anti-hCG beta-subunit was used as the first antibody. A positive fluorescence reaction was found in all human specimens analyzed and in positive controls (choriocarcinoma cells). No fluorescence was detected in other species studied (sheep, pig, goat, horse, bull, and guinea pig), nor in the negative controls. These findings open a new research area on the physiologic role of this hCG-like substance in human reproduction.