Abstract
The extent of binding of anti-D antibody to intact Rh (D) positive human erythrocytes at -2.5° was approximately one-third that at.3-°. An Arrhenius plot of the temperature dependence of antibody binding showed a clear and reproducible discontinuity at approximately 6-8°. Phospholipasc A2 digestion of the intact erythrocytes resulted in a diminuticr. of exclusively phosphatidylcholine (PC) from the membrane, and an approximately parallel loss of Rh antigen activity at 37° to about 50% of the original. An Arrhenius slot showed no change in the temperature dependence below 6-8° but significant diminution above that point suggesting that the outer membrane PC is involved in Rh(D) antigen activity manifested above that temperature.