[Experimental autoimmune orchitis].

Experimental autoimmune orchitis (EAO) has been extensively studied in spite of which its pathogenic mechanisms are still poorly understood. It has been mostly induced in guinea pigs using spermatozoa or a testicular homogenate plus adjuvants. Initially, the aim of our work was to establish if non-spermatic antigens, such as extracellular components of the walls of seminiferous tubules, were able to induce an autoimmune orchitis. For this purpose, we obtained from rat testes: a) a preparation rich in basement membranes of seminiferous tubules (STBM) and b) a soluble fraction of STBM, non-related to collagen (D-STBM), presenting common antigenic determinants with laminin, the main non-collagen glycoprotein of basement membranes. Fifty per cent of rats immunized with STBM, D-STBM or a murine laminin, developed a multifocal and moderate damage of the testes characterized by mild interstitial cell infiltrates, alterations of the basement membranes of seminiferous tubules and Sertoli cells, sloughing of the germinal epithelium and tubular atrophy. Circulating antibodies and a specific cellular immune response were also detected. Moreover, rats passively injected with an heterologous anti-D-STBM serum developed a similar testicular lesion and showed Ig deposits on the basement membranes of seminiferous tubules. In relation to the pathogenic mechanisms of EAO, we studied the variations of T and B cell populations, at the immunization draining lymph nodes, during the development of orchitis. A severe EAO was induced in Wistar rats by immunization with an homologous testes homogenate plus adjuvants.(ABSTRACT TRUNCATED AT 250 WORDS)