Characterization of human IgG Fc receptors.
A murine monoclonal antibody, KuFc79, has been developed that reacts with human IgG Fc receptors on monocytes, B lymphocytes, and granulocytes. The specificity of KuFc79 for Fc receptors was demonstrated by the ability of Fab fragments to block Fc-mediated phagocytosis by monocytes. This finding was further substantiated by the decrease of KuFc79 binding to monocytes and granulocytes (58 and 70%, respectively) after modulation of surface IgG receptors with aggregated IgG. In addition, Fab KuFc79-conjugated Sepharose was used to isolate functional IgG Fc-binding molecules from soluble extracts of the human monocyte-like cell line U937. By immunoprecipitation, it was further shown that KuFc79 immunoprecipitated molecules of 42,000 and 70,000 daltons from U937 and a human lymphoblastoid cell line, SB. A lower m.w. species of approximately 33,000 was also precipitable from granulocytes. Extensive microheterogeneity of these molecules was noted by isoelectric focusing, which appears to be due to differential sialation.
Vaughn
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Taylor
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Mohanakumar
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D000818:Animals; D000911:Antibodies, Monoclonal / Q000502:physiology; D000918:Antibody Specificity; D001666:Binding Sites, Antibody; D001667:Binding, Competitive; D005455:Fluorescent Antibody Technique; D006023:Glycoproteins / Q000378:metabolism; D006801:Humans; D007140:Immunoglobulin Fab Fragments / Q000502:physiology; D007074:Immunoglobulin G / Q000378:metabolism* / Q000502:physiology; D008214:Lymphocytes / Q000145:classification / Q000378:metabolism; D051379:Mice; D008807:Mice, Inbred BALB C; D008970:Molecular Weight; D009000:Monocytes / Q000276:immunology; D010587:Phagocytosis; D011233:Precipitin Tests; D011961:Receptors, Fc / Q000276:immunology / Q000302:isolation & purification / Q000378:metabolism*; D017452:Receptors, IgG
D000911:Antibodies, Monoclonal; D006023:Glycoproteins; D007140:Immunoglobulin Fab Fragments; D007074:Immunoglobulin G; D011961:Receptors, Fc; D017452:Receptors, IgG