Expression of H-Y antigen by female mice carrying Sxr.

The minor transplantation antigen H-Y can cause graft rejection and can stimulate the generation of H-2-restricted T cell responses. We have used both responses to type karyotypically abnormal mice for the presence of H-Y antigen, in order to investigate the role of H-Y in sex determination. The mice under scrutiny were Sxr5-carrying females derived by crossing females carrying the T(16;X)16H translocation with Sxr carrying males. These females were fully fertile and were H-Y positive. These results are consistent with the testis determining gene, Tdy, which may or may not be H-Y, having a threshold effect on testis differentiation during embryogenesis. They also show that the presence of H-Y in adult females does not impair reproduction.