Structural similarities between a product of the T/t locus isolated from sperm and teratoma cells, and H 2 antigens isolated from splenocytes

Molecules specified by the H 2 linked T/t locus in the mouse are expressed on H 2 negative cells such as early embryos, sperm, and teratoma cells. By means of enzymatic radioiodination of cells and immunoprecipitation of lysates with congenic antiserum, one of these molecules, known as F9, has been obtained from sperm and teratoma cells and compared to H 2 isolated from murine splenocytes. Our studies indicate that both H 2 and F9 have identical molecular weights and subunit structure, including the presence of a B2 microglobulin like subunit. These findings, taken together with previous studies of TL alloantigens, suggest that a number of gene products of the 9th linkage group show structural homology with each other and, in addition, with immunoglobulin. The genes in question may therefore have arisen from a primitive gene concerned with cellular recognition.