Another example of an antibody reacting optimally with p red cells

An antibody is described that reacted strongly with red cells of the p(Tj(a-)) phenotype and moderately to strongly with cord red cells of the P2 phenotype. The antibody failed to react, or reacted very weakly, with red cells of the P1k and phenotypes and with the red cells of five children of a p individual, ahd reacted weakly with occasional red cell samples from adults of the P2 phenotype. These results suggest that the antibody does not detect a product of the p gene but instead detects a P system precursor substance. In p individuals this P system precursor substance is not altered by the p genes. In individuals of the P1 or P2 phenocursor substance is not altered by the p genes. In individuals of the P1 or P2 phenotype this precursor substance is apparently converted to P1 and/or P antigens by the P1 or P2 genes.