Quantitative estimation of HLA-A and HLA-B antigens carrying the Bw4 supertypic specificity in human peripheral blood lymphocytes.

A monoclonal antibody specific for HLA-Bw4 was employed for the quantitative estimation of class I antigens on human peripheral blood lymphocytes and on the human macrophage cell line U 937. The epitopes reactive with the HLA-Bw4-specific antibody, which are present on different antigens coded by the HLA-A or the HLA-B locus, were characterized in terms of equilibrium and kinetic binding parameters. The level of expression of class I antigens on human lymphocytes was found to be in direct proportion to the gene dose. Variations between donors of the same phenotype were of minor importance. Estimation of the association constant, association rate constant, and half-life of dissociation for the interaction of the antibody with lymphocytes heterozygous for either HLA-A24, HLA-A32, HLA-A9, or HLA-Bw4 strongly suggested that the public antigenic determinant shared by these antigens is identical.