Characterization and developmental expression of the chicken B-G heterodimer

Monoclonal antibody R7-3 recognized an erythroid specific cell surface molecule with a m.w. of approximately 98 kilodaltons (Kd) under nonreducing conditions and molecules of 40 and 44 Kd under reducing conditions on both embryonic- and adult-derived peripheral RBC. Immunochemical characterization, including limited peptide map analyses of these molecules, provided evidence that mAb R7-3 was recognizing the MHC coded B-G heterodimer. This is the first report of a monoclonal antibody that recognizes the B-G heterodimer. Affinity binding studies suggested that mAb R7-3 preferentially recognized the 44 Kd molecule. Immune depletion analyses demonstrated the presence of a single population of B-G heterodimers. Endoglycosidase-F and neuraminidase digestions suggested that the 44 and 40 Kd molecules contained very little, if any, carbohydrate. B-G heterodimer expression was examined on primitive and definitive RBC during embryonic development. B-G heterodimer expression was not detected on RBC of other avians.