Dynamism of the development of "Fc receptor-blocking antibodies" after immunization with buffy coat.

Eight healthy male blood donors who had not received transfusion previously, were immunized 5 times at 6-week intervals. The immunization was carried out with "buffy coat" separated from 400 ml freshly obtained donor blood. Donor-recipient pairs showed a mismatching for 1 to 4 HLA antigens. The production of HLA antibodies could be demonstrated in 4 patients during the repeated immunizations. Fc receptor-blocking antibody activity was determined with the erythrocyte antibody inhibition (EAI) method in serum samples for the recipients. An increase in the Fc receptor-blocking antibody serum level could be detected already on the second day after the first immune stimulus. Fc receptor-blocking activity was maximum on the 10th day after immunization. After repeated immune stimuli, the increased non-specific Fc receptor-blocking antibody activity was demonstrated independently of the appearance of specific HLA cytotoxic antibodies.