Lymphocyte killer activity in individuals sensitized against antigen-D assessed by direct ADCC lysis of O,Rh-positive erythrocytes.

Lymphocytes from individuals sensitized against the Rh-D antigen were found to lyse O,Rh-positive erythrocytes. The controls consisted of individuals non-sensitized against D antigen. The lytic effect in the absence of additional in vitro added specific antibody was very high in sensitized individuals, but low in the control group. Lytic effect decreased after treating the lymphocytes of sensitized donors with trypsin, but it remained unchanged in the control group. These results suggest that the sensitized donors possessed lymphocytes with specific antibodies in vivo. This phenomenon could prove a valuable diagnostic tool in recognizing responder and non-responder donors in the early phase of immunization.