Stimulation of human NK-cell activity by cultured cells. I. Response of normals

Abstract
Natural cell‐mediated cytotoxicity, observed on co‐cultivation of peripheral blood lymphocytes (PBL) with malignant melanoma tumor cells (M4), is described. The activity was inhibited when PBL were cultured in autologous serum. Studies using competitive inhibition with cold targets and stimulation of PBL with other tumor cell lines failed to detect specificity.