A monoclonal antibody to the HLA-DR product recognizes a polymorphic Ia determinant in mice.

A rat monoclonal antibody which recognizes a product of the HLA-DR locus is described. The determinant recognized by this antibody is monomorphic in man but polymorphic in mice. Mapping studies with inbred and recombinant strains of mice show that this antigen as associated with H-2 haplotypes b, d and q and is coded for by genes within the I-A subregion.