Murine non-lymphoid tumors are lysed by a combination of NK and NC cells.

Natural cell-mediated cytotoxicity (NCMC) against a variety of tumor targets is mediated by a heterogeneous group of effector cells with the natural killer (NK) and natural cytotoxic (NC) cells being the predominant prototypes in mice. This report shows that non-lymphoid tumor targets, mostly derived from chemically induced fibrosarcomas, are susceptible to either (1) NK-mediated lysis with all the activity being the function of a poly-IC augmentable Qa-5+ effector cell; (2) NC-mediated lysis with all activity being the function of a Qa-5- cell not augmented by poly-IC; and (3) a combination of NK-and NC-mediated lysis with activity being the function of both Qa-5+ and Qa-5- cells, the NK (Qa-5+) augmented by poly-IC. These studies further support the view that murine NC and NK cells are distinct and collectively make up the NCMC system, and also that the previous association of NK cells with lymphoid tumor lysis and NC cells with non-lymphoid tumor lysis is not a valid one.