Characteristics of the effector cells mediating cytotoxicity against antibody-coated target cells. II. The mouse nonadherent K cell

A cell of lymphoid morphology capable of killing antibody-coated chicken erythrocytes was isolated from nonimmune mouse spleen using a combination of carbonyl iron treatment and glass bead column passage. This nonphagocytic effector cell, which is referred to as the nonadherent K (killer) cell, is distinguished from the non-phagocytic myeloid K cell described earlier (Greenberg, A.H., Shen, L. and Roitt, I.M., Clin. Exp. Immunol. 1973. 15: 251) by its relatively weak surface adherence properties and low concentration within the mouse spleen. The cell is further characterized by its relatively large size, lack of theta or immunoglobulin determinants, the presence of Mg⁺⁺-independent complement receptors, affinity for aggregated IgG₂ myeloma proteins, inhibition by cytochalasin B and good survival in cell culture. The possible lineage of the cell is discussed.