Role of the ABO, Secretor, and Lewis determinants in the primed lymphocyte test.

The antigenic determinants of the combined ABO, Lewis, and Secretor genes have been detected on the surface of lymphocytes by the lymphocytotoxicity test. We have studied the role of these determinants in the primed lymphocyte test (PLT), and the data demonstrate that Lewis incompatibility causes proliferative responses in PLT. On the other hand, no effects of ABO and Secretor incompatibilities were observed in this test. The frequency of the alloantigen-reactive cells (ARC) responding to Lewis and HLA-DR antigens in PLT was estimated by the limiting dilution analysis. The frequency of ARC to allogeneic Lewis-negative donors, who are positive for the sensitizing HLA-DR antigens ranged between 1:58 and 1:97. The incidence of ARC to Lewis-positive allogeneic donors who did not carry the sensitizing HLA-DR specificity was 1:94 to 1:142. These results demonstrate the presence of lymphocyte clones that are able to respond to antigens of the Lewis system. This study suggests that non-HLA antigens belonging to the Lewis system can cause stimulation of lymphocytes in the PLT test.