Immunological unresponsiveness during induction of experimental autoimmune orchitis in guinea-pigs: studies in vivo and in vitro.

Groups of male and female guinea-pigs were immunized with homologous sperm derived from testis (TS) or epididyimis (ES) in Freund's complete adjuvant (FCA). In vivo investigations included skin tests at 2 weeks and development of aspermatogenesis (testis weight) at 4 weeks; in vitro assays were inhibition of migration of peritoneal exudate cells (PEC) and culture of blood leucocytes (lymphocyte transformation) at weekly intervals after immunization. Antigens used were heat-treated extracts of sperm used for immunization (BTS, BES); cells were also cultured simultaneously with PPD. Skin tests revealed anergy in males as compared with females: a larger quantity of antigen which caused partial unresponsiveness in females, caused profound unresponsiveness in males although the aspermatogenesis was less severe. In vitro tests also showed anergy during the active stages of the orchitis. This was non-specific for PEC (specific unresponsiveness was not excluded), but blood leucocytes showed only specific unresponsiveness (to BES). These and previous studies suggest that the unresponsiveness results from a desensitisation by sperm antigens released during the development of aspermatogenesis.