Native and inducible levels of natural cytotoxicity in lymph nodes draining mammary carcinoma.

Lymphocytes isolated from axillary nodes draining breast carcinoma possess variable natural cytotoxic capacity. Augmentation of lymph node cell (LNC) cytotoxicity by interferon (IFN) is also variable, with only some populations displaying potentiated lysis following exposure to either IFN-a or gene-cloned IFN-a2. Where present the IFN-induced augmentation of LNC cytotoxicity was invariably weaker than that observed following similar treatment of autochthonous peripheral blood mononuclear cells (PBMC). Irrespective of their responsiveness to IFN the cytotoxic activity of all LNC preparations examined was significantly increased following pre-incubation with either staphylococcal enterotoxin A (SEA) or factors elaborated by lectin-pulsed allogeneic LNC. THe induction or amplification fo LNC-mediated natural cytotoxicity by lymphokines may provide a local potentiation of natural immune function at the host : tumour interface.