Genetic susceptibility to testicular autoimmunity: comparison between postthymectomy and postvasectomy models in mice

The genetic susceptibility was compared in six mouse strains to both postthymectomy (post-Tx) autoimmune orchitis, induced by thymectomy at Day 3, and postvasectomy (post-Vx) autoimmune testicular lesions, induced by bilateral vasectomy with ligation at 2 months of age. Results from mice examined at 4 months of age showed that the strain distribution of the post-Vx testicular lesion was similar to that of post-Tx orchitis. The SWR/J strain was susceptible, the DBA/1J, C57L/J, BALB/cJ and probably C57BL/10J strains were resistant, and the A/J strain was intermediate. Anti-sperm antibodies (IgG) were produced to varying degrees in all strains of vasectomized mice irrespective of the testicular lesion. Neither the development of the testicular lesion nor antibody formation was associated with the particular H-2 haplotypes of mice in either system. Neonatal thymectomy significantly enhanced anti-sperm antibody formation in the post-Vx system and resulted in a mild testicular atrophy in a resistant strain BALB/cBy. All these data suggest that a gene(s) outside the major histocompatibility complex may determine the genetic susceptibility to testicular autoimmunity, possibly at the testicular level.