Immunohistochemical localization of a plasma protein (glycoprotein 60) which inhibits complement-mediated prevention of immune precipitation.

Using various immunocytochemical techniques it has been shown that glycoprotein 60 (gp60), an IgG Fc-binding protein recently isolated from normal human plasma, is found localized in human hepatocytes, platelets and a subpopulation of normal peripheral blood lymphocytes (PBL). This protein, which appears to be identical to a 60,000 MW IgG-binding protein (60-IBF) previously isolated from normal human PBL culture supernatants, also appears to be distinct from the three well-defined leucocyte Fc gamma-receptors: Fc gamma RI, Fc gamma RII and Fc gamma RIII.