Association constants of anti-hapten monoclonal IgG1 with mouse Fc gamma RII in the presence and absence of hapten.

The binding of five different mouse monoclonal anti-dinitrophenyl (DNP) IgGl monomers, in the presence and absence of DNP-glycine, to Fc gamma RII on the mouse macrophage-like cell line J774 has been investigated. Membrane association constants were estimated using a competitive radioimmunoassay in which the ability of the IgG1 monomers to block the binding of 125I-labelled Fabs of the anti-Fc gamma RII monoclonal antibody 2.4G2 was monitored. The IgG1-Fc gamma RII association constants ranged from (8 +/- 1) x 10(4) M-1 to (6 +/- 2) x 10(5) M-1. No large differences in the IgG1-Fc gamma RII association constants were measured for different IgG1 antibodies or for any single IgG1 antibody in the presence and absence of DNP-glycine.