Immunoglobulins and immunoglobulin receptors associated with human malignant tumors.

Over the past five years 86 malignant tumors were assayed for cell surface IgG, elutable Ag-Ab complexes, and/or cell surface Fc receptors. Surface IgG was measured by indirect radioimmunoassay, using single-cell suspensions and tumor eluates. Fc receptors in tissue sections were identified by the closed chamber technique. The results confirm our previous finding that human tumors are coated in vivo with IgG and that there is a population of cells within solid tumors capable of binding Ag-Ab complexes. In addition, Ag-Ab complexes appear to attach to the cell surface membrane by the Fc zone of antibody. Ag-Ab binding was inhibited by antibody raised against the tumor. Indirect complement consumption assay indicated the presence of Ag-Ab complexes in tumor eluates. It appears that most cell surface immunoglobulin is complexed.