New H-2-linked cell and serum antigens.

A system of two public serum antigens, alpha and delta, whose distribution in inbred strains of mice is different from that of all serum antigens known, is described. Their distribution in the H-2 congenic and in the recombinant inbred HTG strain indicates that they are determined by a gene(s) tightly linked to H-2. Backcross tests confirmed this; only 1.1-cM recombinants were found. The gene(s) is located at the D side of H-2. The immunogenicity of the serum specificities in A/Sn animals, but not in other strains, is sex-limited. These serum antigens are also present in most tissues and, in high amounts, in red blood cells. No sex differences in the absorbing capacity of tissues or the agglutinability of red blood cells were found. All these findings indicate that alpha and delta antigens belong to a new H-2-linked system. A relationship with the recently found new class I genes is suggested.