ISOLATION OF AN FC-GAMMA-BINDING PROTEIN FROM CELL-MEMBRANE OF A MACROPHAGE-LIKE CELL LINE (P388D) AFTER DETERGENT SOLUBILIZATION

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  • 1 January 1978
    • journal article
    • research article
    • Vol. 120  (3) , 709-715
Abstract
Lactoperoxidase-catalyzed iodination, NP-40 [Nonidet P-40] lysis and subsequent affinity chromatography on Ig[immunoglobulin]G-Sepharose were used in an attempt to define some of the molecular properties of the Fc receptor of P388D1, a macrophage-like mouse tumor line. Radioiodinated material retained on columns of Sepharose coupled to monomeric mouse IgG2a or monomeric human IgG1 appeared on SDS [sodium dodecyl sulfate] polyacrylamide gel electrophoresis to contain principally 3 labeled components, a major band of about 57,000 MW, and 2 minor bands of 28,000 and 24,000 MW. The mobilities of these components changed little on reduction, which suggested that they represented single polypeptide chains. An identical pattern was obtained with Sepharose-linked Fc fragments of human IgG1, but neither Fab fragments of IgG1 nor IgM appeared to bind these components. Since the specificity of binding to the immobilized proteins is the same as that observed in vivo, these proteins probably represent all or some portion of the P338D1 Fc receptor.