Blood group D antigen content of nucleated red cell precursors

The D antigen content of nucleated red cell precursors in human bone marrow was estimated using autoradiography and 125I-anti-D. D antigen first appeared in the pronormoblast, and the quantity of antigen progressively increased during red cell maturation. Maximal anti-D binding occurred on mature red blood cells. Pronormoblasts, basophilic normoblasts, polychromatophilic normoblasts, and orthochromatic normoblasts, respectively, had approximately 1/4, 1/2, 2/3, and 3/4 the quantity of antigen found on mature red cells. None of the other cell types were found in bone marrow labeled with anti-D.