Comparison of the cytotoxic activities of different human lymphoid tissues

Normal human lymphoid cells from peripheral blood, spleen, tonsils and thymus were examined for their ability to mediate three different cytotoxic effector cell functions: antibody-dependent cellular cytotoxicity (ADCC); lectin-induced cellular cytotoxicity (LICC) and natural killer activity (NK), against 51Cr labelled erythroid and tumor target cells. We found a hierarchy of cytotoxic activities in the different lymphoid tissues. Peripheral blood and spleen cells were able to mediate LICC, ADCC and NK activities. Tonsil cells showed a natural segregation of the different cytotoxic functions: NK and ADCC activity against tumor target cells were absent, whereas LICC activity was fully present. With respect to ADCC activity against erythroid targets, tonsil cells showed low, but significant, cytotoxicity. Thymus cells had no detectable ADCC, NK and LICC activities. Correlation in the different lymphoid tissues between cytotoxic activities and cell surface marker studies revealed: (a) that the presence of E-SRBC rosette forming cells was not always associated with the detection of LICC activity, as is the case with the thymus; (b) that, in the absence of detectable Eox-7S rosette forming cells (thymus and tonsils), NK and ADCC activities against tumor cells were always absent, but LICC was observed (tonsils), indicating that the presence of this Fc(7S) receptor bearing cells is strongly associated with the expression of NK and ADCC but not with LICC.