Notes on the Ena and U antigens of Ena(En.OP) heterozygotes, and the U antigen of En(a--) individuals.

Using two anti-Ena antibodies, from which anti-Wrb had been removed, and anti-U antibodies, the authors have failed to demonstrate any difference in the amounts of Ena and U antigens on the red blood cells of individuals with one and two functioning Ena(En.OP) genes. Two En(a--) samples, one from an individual who is En/En (En.op/En.op) and the other En/Mk (En.op/Mk), could not be distinguished from U-positive samples from individuals with two functioning U (U.OP) genes in dosage studies with anti-U.