Head-to-head agglutination of ram and boar epididymal spermatozoa and evidence for an epididymal antagglutinin

Summary. Spermatozoa from the corpus epididymidis of boars and rams showed head-to-head agglutination when diluted. The occurrence of agglutination coincided with the appearance of motility but preceded the ability to bind to zona-free hamster eggs. Head-to-head agglutination was inhibited by the addition of caudal epididymal plasma. A protein acting as an antagglutinin on spermatozoa from the corpus epididymidis was extracted from cauda epididymal plasma and partly purified.