Effect of antisperm sera on the acrosomal proteolytic activity in vitro

The effect of isoimmune antisperm sera from heifers and the effect of sera from cows and women with unexplained infertility were studied on the sperm acrosomal proteolytic activity (SAPA) of bull and human spermatozoa. All the sera were preliminarily tested by the method of Kibrick, and the cow sera were additionally tested by method of Isojima et al. Ejaculated bull and human spermatozoa were incubated in a medium containing antisera. SAPA was monitored on KODAK AR-10 autoradiographic plates according to Wendt et al. In some experiments the bull spermatozoa were preincubated in a medium containing 30% follicular fluid to induce capacitation and acrosomal reaction. The incubation of spermatozoa in isoimmune sera led to a marked inhibition of SAPA. A similar effect was observed when sera from cows and women with unexplained infertility were used. Preincubation of bull spermatozoa in follicular fluid intensified SAPA. The subsequent treatment with sera from infertile cows with high titres of spermagglutinins strongly inhibited this activity.