Binding of Aggregated IgG by Human B Lymphocytes Independent of Fc Receptors

We present data concerning the mechanism of the binding of aggregated IgG and of IgG‐sensitized erythrocytes by different human lymphocyte‐like cells. The results showed that the two phenomena are related to different subpopulations of lymphocytes. By fractionation and depletion studies of B lymphocytes, T lymphocytes, and lymphocyte‐like cells binding IgG‐sensitized erythrocytes (EA‐RFC), it was demonstrated that binding of aggregated IgG is related to B lymphocytes, whereas binding of IgG‐sensitized erythrocytes depends on another subpopulation of lymphocyte‐like cells. Whereas binding of IgG‐sensitized erythrocytes by EA‐RFCs depends entirely on the Fc fragment, binding studies with IgG fragments suggested that the interaction of aggregated IgG with B lymphocytes is different.