title: Contribution of mannose receptor to signal transduction in Fc gamma receptor-mediated phagocytosis of mouse peritoneal macrophages induced by liposomes.
abstract: The contribution of mannose receptors on the cell surface of mouse peritoneal macrophages to the process of liposome-induced phagocytosis of immunoglobulin G-opsonized sheep red blood cells (SRBCs) through Fc gamma receptor has been investigated. Fc gamma receptor-mediated phagocytosis of opsonized SRBCs was activated by modified alpha 2-macroglobulin, which was produced in the incubation mixture of alpha 2-macroglobulin and liposome-treated splenic B cells. The phagocytosis was specifically inhibited by the addition of D-mannose, and the inhibition was dependent on the D-mannose concentration. The binding of modified alpha 2-macroglobulin to macrophages was also reduced by the addition of D-mannose. The activation effect of modified alpha 2-macroglobulin was not inhibited when in the presence of alpha 2-macroglobulin-trypsin and -methylamine complexes. In the presence of cycloheximide, activated phagocytosis was reduced to the control level. By Scatchard plot analysis of IgG binding studies, the number of Fc gamma receptors of a macrophage had been increased to 4.6-fold that of a control macrophage by treatment with modified alpha 2-macroglobulin. These findings suggest that macrophage mannose receptors are involved in activating the process of Fc gamma receptor-mediated phagocytosis of opsonized SRBCs induced by modified alpha 2-macroglobulin. Lectins may participate in a signal transduction in macrophage activation by liposomes.
authors.affiliation: Tokyo College of Pharmacy, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Murai
authors.forename: Y
authors.initials: Y
authors.lastname: Aramaki
authors.forename: S
authors.initials: S
authors.lastname: Tsuchiya
mesh_terms: D000818:Animals; D003513:Cycloheximide / Q000494:pharmacology; D004912:Erythrocytes / Q000276:immunology; D007074:Immunoglobulin G / Q000276:immunology; D037181:Lectins, C-Type; D008081:Liposomes / Q000494:pharmacology*; D017737:Macrophages, Peritoneal / Q000187:drug effects / Q000378:metabolism / Q000502:physiology*; D008297:Male; D008358:Mannose / Q000378:metabolism / Q000494:pharmacology; D000090323:Mannose Receptor; D037241:Mannose-Binding Lectins; D051379:Mice; D008807:Mice, Inbred BALB C; D009005:Monosaccharides / Q000494:pharmacology; D010587:Phagocytosis / Q000187:drug effects / Q000502:physiology*; D011956:Receptors, Cell Surface / Q000187:drug effects / Q000378:metabolism / Q000502:physiology*; D017452:Receptors, IgG / Q000187:drug effects / Q000378:metabolism / Q000502:physiology*; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology*; D013379:Substrate Specificity; D000511:alpha-Macroglobulins / Q000378:metabolism
chemical_list: D007074:Immunoglobulin G; D037181:Lectins, C-Type; D008081:Liposomes; D000090323:Mannose Receptor; D037241:Mannose-Binding Lectins; D009005:Monosaccharides; D011956:Receptors, Cell Surface; D017452:Receptors, IgG; D000511:alpha-Macroglobulins; D003513:Cycloheximide; D008358:Mannose