The 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 suspension indicated that N cells were neither T nor B cells. Like B cells, N cells did not form rosettes with sheep erythrocytes; they were retained by columns coated with lg or antiserum to lg and died preferentially when stored at an ambient temperature. However, N cells were differentiated from B cells by their inability to form complement-receptor rosettes and by their survival when incubated at 30 degrees C. The effect of the nonselective cytotoxic cell must be differentiated from selective activity in studies of specificity for cell-mediated cytotoxicity.