Description of monoclonal antibody defining an HLA allotypic determinant that includes specificities within the B5 cross-reacting group.

The selection and characterization of a cloned murine monoclonal antibody (4D12) that defines an HLA allotypic determinant is described. Antibody 4D12 immunoprecipitates HLA heavy and light chains. From studies on 4D12 reactivity with a large panel of well-characterized target cells, antibody 4D12 defines a public HLA determinant that includes specificities within but not identical to the B5 cross-reacting group. Antibody 4D12 should be useful in the study of HLA-B5--related supratypic antigens.