Binding of human IgG to cultured urogenital tumor cells.

Binding of human IgG by the Fc portion of the immunoglobulin molecule was detected on established human tumor cell lines by indirect immunofluorescence microscopy, cytofluorography, quantitative absorption, and rosette formation with the use of antibody-coated erythrocytes. Of the nonlymphoid tumors tested, IgG binding was restricted to the cell membranes of certain prostate and urinary bladder tumor cell lines. Although most cell lines tested shared a common antigenic determinant with monocytes and granulocytes, these cells did not express T- and B-cell antigens, the complement 3b receptor, or bind a monoclonal antibody specific for the Fc receptor expressed on human neutrophils. The facts that IgG binding was present on long-term established tumor lines and was not influenced by in vitro passage provide evidence that these properties are intrinsic to the tumor cells and may play some role in the pathophysiology of these tumors.