Isolation and characterization of a human mononuclear cell Fc receptor

These studies show that human peripheral mononuclear cells have a surface receptor of 60,000 mol. wt (and possibly a disulfide bonded dimeric form of 120,000) which has affinity for heat-aggregated human IgG, IgG₁ myeloma proteins, or the Fc⁺ fragments of either of these but not to F(ab')₂ fragments of IgG. Precipitates of this receptor contain 0.5–1% of the total number of TCA precipitable counts incorporated into the surface membrane. Since this structure was found trysininsensitive and was not identified on the cell membranes of cultured human T cell lines, it appears to be a surface receptor for the Fc portion of IgG.