NONSELECTIVE CYTOTOXIC CELL (N CELL)

When effector lymphocytes were reacted with cultured human tumors, the total cytotoxic reaction could be divided into selective and nonselective components. The nonselective part of the reaction was due to a cell type called N cells. Fractionation of effector suspensions indicated that N cells were neither T[thymus-derived] nor B[bone marrow-derived] cells. Like B cells, N cells did not form rosettes with sheep erythrocytes. They were retained by columns coated with Ig[immunoglobulin] or antiserum to Ig and died preferentially when stored at an ambient temperature. N cells were differentiated from B cells by their inability to form complement-receptor rosettes and their survival when incubated at 30.degree. C. The effect of the N cell must be differentiated from selective activity in studies of specificity for cell-mediated cytotoxicity.