Quantitative studies on the Rh-antigen D. Effect of the C gene.

Using an automated antiglobulin consumption test and Scatchard's analysis, the authors measured the number of D antigen epitopes on each of 46 samples of washed red cells (RBC) that represented six different Rh phenotypes. A clear D dosage effect was observed only when C was missing from the Rh genome, which confirmed the previously recognized suppressive effect of C. Thus, RBC of the Rh phenotype R2R2 had almost twice as many D epitopes (mean, 30,300/cell) as RBC of the Rh phenotypes R2r and R0r (means, 17,200 and 16,500 respectively). The data indicated that C in trans and cis suppressed similar amounts of D epitopes.