The biologic activity of affinity cross-linked oligomers of rabbit immunogloblin G as tested by antigody-dependent cell-mediated cytolysis (ADCC).

ABSTRACT

The abilities of normal spleen cells and macrophage-like and lymphocyte-like tumor cells to serve as effectors in antibody-dependent cell-mediated cytolytic (ADCC) reactions were examined. It was observed that those cells which contained Fc receptors on their surfaces were effective mediators of ADCC whereas those not bearing Fc receptors were inactive. Oligomers of IgG were able to inhibit the ADCC reaction and, with the macrophage line, inhibition and binding closely paralleled each other. With the lymphocyte lines, a large degree of inhibition of ADCC occurred when only small amounts of oligomers were bound; with normal spleen cells inhibition occurred in the same range of oligomer concentrations required to inhibit the tumor-mediated ADCC reactions. The data suggest that the interaction between antibody-coated erythrocytes and effector cells is unexpectedly weak.