IDENTIFICATION OF ANTI-AGGLUTININ FOR SPERMATOZOA IN EPIDIDYMAL BOAR PLASMA

The present report identifies epididymal boar anti-agglutinin and exam ines its effect on sperm motility. Boar spermatozoa from the cauda epi didymidis were washed and incubated in modified Krebs-Ringer bicarbona te at 37-degrees-C (5% CO2 in air). In the samples washed three or fiv e times and then incubated for 3-5 h, higher rates (72-79%) of spermat ozoa were associated with one another at the acrosomal region, mainly in groups of 2-5 cells (head-to-head agglutination), and many cells ex hibited intensively flagellant and/or circular types of movement but r arely progressive motility. The addition of epididymal plasma or 25 kD a protein purified from it markedly inhibited the occurrence of head-t o-head agglutination in washed spermatozoa, whereas heat treatment and subsequent removal of insoluble materials reduced the anti-agglutinat ion activity of epididymal plasma. The percentages of progressively mo tile cells in the samples incubated with epididymal plasma or 25 kDa e pididymal protein rose coincident with the reduction of sperm agglutin ation. These findings demonstrate that the 25 kDa epididymal protein i s an anti-agglutinin for the cauda spermatozoa and that it effectively functions to maintain progressive motility of the cells in vitro. (C) 1994 Wiley-Liss, Inc.