The Influence of Race and Phenotype on the Erythrocyte D Antigen Studied by I131--labeled Anti--D

A method for the preparation of I¹³¹-labeled anti-D eluates (I^unknown] anti-D)specific for the D antigen by adsorption and elution from intact D positivered cells is presented. A standard D antigen reference system for the quantitative comparison of the red cell D antigen from various donors was developedon the basis of kinetic studies of the effect of pH, temperature and antigenconcentration on the I^unknown] anti-D reaction with the D antigen. The red cell Dantigen determinations of the blood from 33 Negro and 102 Caucasiandonors showed wide monomodal frequency distributions which indicate aheterogeneity of quantitative D antigen reactivity consistent with previousserologic and I¹³¹-labeled anti-D studies. The average red cell D antigenreactivity of the 20 probable D homozygote and 14 established D hemizygoteCaucasian donors was similar to the D antigen reactivity of the 102 randomCaucasian donors. The red cell D antigen reactivity was strongly depressedby the C antigen (or C gene) in Caucasian bloods and enhanced by the Eantigen (or E gene) in Negro bloods. The E antigen (or E gene) may alsohave enhanced the D antigen reactivity in red cells from Caucasian donors,but the difference in D zygosity provides an alternative explanation for theresults. The marked influence on red cell D antigen reactivity in the presenceof the C and E antigen may well have obscured any lesser influence of Dzygosity.

Accepted on December 6, 1962