A new cell surface molecule closely related to mouse class I transplantation antigens.

The "37" H-2 class I mouse gene, located in the Tla complex, is poorly polymorphic and is transcribed in a wide variety of cells and tissues. Using antisera directed against peptides deduced from the gene sequence, we demonstrate that the 37 gene encodes a 45.5-kDa cell surface glycoprotein. This protein, initially identified on the surface of mouse L cells transfected with an overexpressing 37 gene, is present on cells such as splenocytes of various mouse strains except those of A/J mice. Thus, mouse cells may express not only the major transplantation antigens encoded by the K and D region genes, but at least one additional poorly polymorphic class I molecule encoded by the 37 gene.