Human monocytes, B lymphocytes, and non-B lymphocytes each have structurally unique Fc(γ) receptors

Human Fc(γ)-binding macromolecules were isolated from subpopulations of mononuclear cells by repetitive affinity chromatography. Mononuclear cells, nylon wool-filtered cells, plastic-nonadherent cells, and plastic-adherent cells from normal donors were radiolabeled by using ¹²⁵I and lactoperoxidase. Washed cells were solubilized in 1% NP-40 buffer containing proteinase inhibitors at 0° C. Fc(γ) receptors were purified on human IgG-Sepharose columns by use of the repetitive affinity chromatography procedure. Analysis by SDS-polyacrylamide gel electrophoresis demonstrated only a 52,000 to 58,000 M(r) Fc(γ) receptor from nonadherent cell populations. Both rosetting and nonrosetting subpopulations of non-B lymphocytes expressed the 52,000 to 58,000 M(r) receptor. The predominant Fc(γ) receptor isolated from plastic-adherent cells was a 60,000 to 68,000 M(r) macromolecule. Cell preparations enriched in B lymphocytes yielded prominent 43,000 M(r) Fc(γ) receptors. Thus human monocytes, B lymphocytes, and non-B lymphocytes each appear to have structurally distinct and unique Fc(γ) receptors.