Demonstration of the dosage effect of Rho(D) antigens on human red blood cells by an EA rosette assay.

Abstract

Utilizing an EA rosette assay, we were able to distinguish genotypic differences of the Rho (D) antigen on human red blood cells (RBC) based on the number of rosettes formed between human peripheral B lymphocytes and RBC optimally sensitized with anti-Rho (D) antibody. In this study, RBC with possible Rh genotypes R1R1 (CDe/CDe), R1r (CDe/cde), R2R2 (cDE/cDE), R2r (cDE/cde) and R1R2 (cDe/cDE) were sensitized with either RhoGAM (anti-D) or Ripley serum (anti-G). When RBC were optimally sensitized with RhoGAM, R1r formed 60% as many rosettes as R1R1 and R2r formed 64% as many rosettes as did R2R2. Using Ripley serum for sensitization and comparing the number of rosettes formed, R1r exhibited 70% of R1R1 and R2r showed 76% R2R2. Furthermore, R1R1 cells sensitized with Ripley serum formed a higher percentage of rosettes than R1R2 or R2R2.