Autoantigenicity of the basal compartment of seminiferous tubules in the rat.

ABSTRACT

The expression of testicular autoantigens has been thought to be restricted to the luminal compartment of the seminiferous tubules. In the present study it was observed that germ cells in the basal compartment of seminiferous tubules and lamina propria of the seminiferous tubule bound antibodies in anti-testis immunosera in vivo after passive transfer of the sera by intra-peritoneal injection. The anti-testis immunosera were prepared in orchiectomised rats to avoid pre-collection adsorption of antibodies in the basal compartment of the seminiferous tubules. When testis-immune sera collected from non-orchiectomised rats or normal sera were transferred no such binding of antibodies to the basal germ cell surface or the lamina propria occurred. In Western blot analysis the anti-testis immune sera prepared in orchiectomised rats defined polypeptides from the adult rat testis with relative MWs of 19-23, 26-28, 30, 34, 38, 40-43, 45-47, 51-52, 56-57, 68, 78 and 97 kDa. The 40-43 kDa band was not detected by sera prepared in non-orchiectomised rats, suggesting that this autoantigen was expressed in the basal compartment of the seminiferous tubules. These observations suggest that the segregation of testicular autoantigens in the luminal compartment of seminiferous tubules is not complete for all of them in the rat and emphasize the role of more dynamic mechanisms in prevention of anti-germ cell autoimmune disease.