title: Effect of interleukin 2 on the inhibition of human natural killer activity by monolayer cells.
abstract: We have previously shown that human endogenous natural killer activity against K562 is inhibited by primary cultures of natural killer-resistant monolayer target cells. In this study we have analyzed the sensitivity of activated killer cells to this inhibitory effect. Interleukin-2 (IL-2), when present during an 18-hr contact of peripheral blood lymphocytes with monolayers, did not affect the inhibition of natural killer cell activity. Pretreatment of effector cells with IL-2 for 24-62 hr before the contact with monolayer cells eradicated the inhibition caused by malignant cells, benign cells remaining inhibitory. The IL-2-pretreated effector cells killed preferentially malignant target cells, although significant cytotoxicity was also detectable against benign cell cultures. The results indicate that activation of killer cells in vitro by IL-2 involves the desensitization of effector cells to the inhibitory signals of target cells, and that the selectivity of IL-2-activated killer cells toward malignant target cells involves weaker inhibition of activated killer cells by malignant cells.
mesh_terms: D002478:Cells, Cultured / Q000276:immunology; D003602:Cytotoxicity, Immunologic; D006801:Humans; D007111:Immunity, Cellular; D007376:Interleukin-2 / Q000502:physiology*; D007694:Killer Cells, Natural / Q000276:immunology*; D014407:Tumor Cells, Cultured / Q000276:immunology*
chemical_list: D007376:Interleukin-2