Inhibition of antibody-dependent cellular cytotoxicity by protein A from Staphylococcus aureus.
Protein A, a cell wall constituent of several strains of Staphylococcus aureus, binds strongly to the Fc portion of immunoglobulins. This investigation demonstrated that such binding can inhibit antibody-dependent cellular cytotoxicity (ADCC). The degree to which ADCC was inhibited depended upon the relative concentrations of protein A and anti-target cell antiserum. Protein A also inhibited the formation of rosettes between antibody-coated sheep red blood cells and lymphoid cells with Fc receptors. We, therefore, conclude that protein A inhibits ADCC by preventing the binding of antibody-coated target cells to Fc receptors on cytotoxic effector cells.
D000906:Antibodies; D001426:Bacterial Proteins / Q000494:pharmacology*; D001667:Binding, Competitive; D003601:Cytotoxicity Tests, Immunologic; D007111:Immunity, Cellular; D007141:Immunoglobulin Fc Fragments; D007165:Immunosuppression Therapy; D008565:Membrane Proteins / Q000494:pharmacology; D013211:Staphylococcus aureus / Q000276:immunology; D013601:T-Lymphocytes / Q000276:immunology
D000906:Antibodies; D001426:Bacterial Proteins; D007141:Immunoglobulin Fc Fragments; D008565:Membrane Proteins