THE SEROLOGICALLY DETECTED H-Y-ANTIGEN REVISITED

H-Y antigen has been defined by various immunological methods includin g graft rejection. T-cell mediated cytolysis, and antiserum cytotoxici ty. The H-Y phenotype is normally associated with the male sex in mamm als. Using specific T-cell clones, two Y-linked genes coding for H-Y e pitopes have been identified in the mouse, Smcy and Uty, and one of th ese genes, SMCY, is also present on the human Y chromosome. Anti-H-Y a ntisera detect a membrane bound antigen associated with beta(2)-microg lobulin, and a soluble protein secreted by testicular Sertoli cells. T he membrane bound antigen appears to be different from the peptides de tected by cytotoxic T-cells, and for the soluble antigen evidence was provided that, in mammals it may be identical with anti-Mullerian horm one. In non-mammalian vertebrates, serological H-Y antigen is associat ed with the heterogametic sex, and sex-reversal of the homogametic sex results in the occurrence of H-Y antigen. Originally, H-Y antigen was believed to be responsible for sex determination, thus representing t he testis-determining factor (TDF) in mammals, but this hypothesis has been disproved by showing that male gonadal differentiation can also occur tin the mouse) in the absence of H-Y antigen. In the meantime, S RY is consider-ed to be TDF. Although it was revealed that the H-Y ant igens as detected by different assays are genetically heterogeneous, t hey are probably involved in male-specific functions in mammals, and p ossibly in the differentiation of the heterogametic sex in non-mammali an vertebrates.