Lack of association of human "B cell" antigens and Fc receptor activity of antibody-dependent cytotoxic lymphocytes.

Heterologous antisera directed against human B cell antigens were tested for their ability to inhibit the function of Fc receptors on human lymphocytes. These antisera coated on the attacking cells in a lymphocyte-dependent antibody-mediated cytotoxic assay inhibited lysis of sensitized target cells. However, the F(ab)2 fragments of the IgG fraction of an anti-human Ia antiserum failed to inhibit the killing of sensitized targets by attacking cells. Antisera against other lymphocyte membrane antigens also inhibited target cell lysis when coated on attacking cells. These results suggest that there is not identity between human B cell antigens and Fc receptors of antibody-dependent cytotoxic lymphocytes.