Quantitative studies of Fc receptors on human monocytes: characterization by binding of homologous and heterologous monomeric IgG and soluble immune complexes of different composition.

摘要: The binding of 125I-labelled monomeric human and rabbit IgG (H-IgG, R-IgG) immune complexes (IC) to monocyte-enriched peripheral blood cells had been investigated quantitatively. Scatchard plots at 4 degrees demonstrated that R-IgG bound the same number Fc receptors per cell (19,000) as H-IgG, but with a lower affinity (2.4 +/- 0.9 X 10(8)/l/mol 3.5 1.1 10(8)l/mol, respectively). Inhibition studies two ligands could mutually inhibit each other, H-IgG having higher inhibitory efficiency versus than reverse. It seems likely reacts receptor for homologous IgG, although affinity. Binding soluble anti-bovine serum albumin (BSA) IC, prepared molar antigen:antibody (Ag:Ab) ratio 2:1 12:1, showed quite different behaviour, IC association constants almost 10-fold R-IgG, six- seven-fold many molecules saturation.