Innate cytotoxicity of CBA mouse spleen cells to Sendai virus-infected L cells

The presence in the spleens of unsensitized CBA mice of cells that are spontaneously cytotoxic for Sendai virus-infected L cells was confirmed. This innate cytotoxic activity to virus-infected cells was shown to exhibit some H-2 restriction. Partial identity of only the D end of the H-2 gene complex between the target and effector cells was required to produce cytolysis. Attempts to characterize the kind of cell active in this system indicated that neither the theta antigen nor the surface immunoglobulin markers were present. Furthermore, the cells appeared to have no adherent or phagocytic properties. The relationship between the effector cells responsible for innate cytotoxicity to virus-infected cells and the natural killer (NK) cells spontaneously cytotoxic for certain tumor cells is discussed.