抄録
Gc globulin (Vitamin D3 binding protein) modified by β-galactosidase of lysophosphatidylcholine-activated B cells and sialidase of T cells has been reported to enhance Fcγ receptor-mediated phagocytosis by murine peritoneal macrophages. In order to clarify the mechanism of enzymatically modified Gc globulin (mGc) -induced enhancement of Fc receptor mediated phagocytosis, we investigated the Fc receptor expression by rosette formation and flow cytometry. mGc enhanced Fc receptor-mediated phagocytosis and rosette formation dose dependently. Modified Gc also enhanced Fcγ receptor-mediated rosette formation in both the trypsintreated and cycloheximide-treated macrophages. Flow cytometric analysis revealed that mGc augmented the cell surface expression of FcγR I and FcγR II in macrophages. Modified Gc-induced enhancement of the Fc receptor-mediated phagocytosis and rosette formation was specifically inhibited by galactose and Nacetylgalactosamine.
These data suggest that mGc enhances Fcγ receptor-mediated phagocytosis in murine peritoneal macrophages by inducing translocation of FcγR I and FcγR II from intracellular storage compartments to the cell surface, and that Gal/GaINAc specific lectin of the macrophage surface membrane may be responsible for the mGc-induced activation.
