Abstract
The number of available [human] G antigen sites within the rhesus system were estimated using trace-labeled antibody. The results given as available antigen sites per cell were as follows: R1R1: 9900-12,200; r''r'': 8200-9700; ryr: 8600; .**GRAPHIC**. 6600; r''xr: 6200; RB1r: 6200; RzRz: 5400; Cdes: 4800-5100; R2R2: 3600-5800; R0R0: 4500-5300; R2r 4200; r"Gr: 1700-3600; RB2r: 1400-1900. The G antigen is detected in optimal amount on C-positive samples. When D is present without C, the number of G sites is apparently dependent on the expression of all the D antigens within the recognized 6 categories of D antigens.