Human monocytes, B lymphocytes, and non-B lymphocytes each have structurally unique Fc gamma receptors.

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Human Fc gamma-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 degrees C. Fc gamma 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 Mr Fc gamma receptor from nonadherent cell populations. Both rosetting and nonrosetting subpopulations of non-B lymphocytes expressed the 52,000 to 58,000 Mr receptor. The predominant Fc gamma receptor isolated from plastic-adherent cells was a 60,000 to 68,000 Mr macromolecule. Cell preparations enriched in B lymphocytes yielded prominent 43,000 Mr Fc gamma receptors. Thus human monocytes, B lymphocytes, and non-B lymphocytes each appear to have structurally distinct and unique Fc gamma receptors.