ANTIBODY-DEPENDENT CELL-MEDIATED CYTO-TOXICITY BY HUMAN-LYMPHOCYTES .2. COMPARISON WITH POLYMORPHONUCLEAR LEUKOCYTES AGAINST ERYTHROCYTE AND NUCLEATED TARGET-CELLS

Abstract

Human peripheral blood lymphocytes were compared to neutrophils with respect to their cytotoxic activity against IgG-sensitized erythrocytes (ox; ORBC) and nucleated (Raji, human Burkitt''s lymphoma) target cells in vitro. Neutrophils were more efficient than lymphocytes in lysing erythrocytes, but lymphocytes were more efficient in lysing Raji cells. The antibody concentrations producing maximal levels of lysis against erythrocyte target cells were similar for both kinds of effector cells and guinea pig complement; in order to obtain Raji cell lysis mediated by neutrophils at a level comparable to that produced by lymphocytes, a higher concentration of antibody was required. Another difference found between the lytic activity of these effector cell populations was kinetics of lysis against erythrocyte targets: a 15 min lag phase was consistently observed only with neutrophil effector cells. Both effector cells lyse Raji cells with similar kinetics and no lag phase. Lysis by lymphocytes and neutrophils was directly proportional to the effector:target cell (E:T) ratio against both target cells. The effector cells were similarly inhibited from lysis of erythrocytes by IgG aggregate, but neutrophil lysis of Raji cells appeared to be more sensitive to inhibition. The neutrophils did not lyse nonsensitized bystander cells, and lymphocytes lysed sheep erythrocyte bystander cells only.