Antibodies to testicular antigens in vasectomized rabbits

Circulating antibodies to testicular antigens have been found in 27 of 46 bilaterally vasectomized rabbits. Approximately 30% of these rabbits had antibodies detectable by tanned cell hemagglutination, 50% by complement fixation. 33% by indirect immunofluorescence (IF) on cryostat sections of testis, 50% by indirect IF on sperm smears, and 11% by precipitation in agar. Indirect IF on sections of testis showed staining in the central and intermediate parts of the seminiferous tubules but no reactions in the basal layers of the tubules or in the interstitial tissue. Indirect IF on sperm smears showed staining of the acrosomal region of spermatozoa. None of the prevasectomy sera from the same rabbits and none of the sera from 13 sham-vasectomized and 20 normal untreated rabbits gave positive reactions. The percentage of positive animals increased with time after vasectomy. Antibodies to testicular antigens were usually detected 6 months following vasectomy, when the incidence was 8% by indirect IF on sperm smears. The percentage increased in the following months, reaching a maximum of 37% at 18 months. Bilaterally vasectomized rabbits with high titers of antibodies to testicular antigens may be a good model for the study of the possible immunological effects of vasectomy.