title: Human dendritic cells handling of binding, uptake and degradation of free and IgG-immune complexed dinitrophenylated human serum albumin in vitro.
abstract: The handling of free and IgG-complexed dinitrophenylated human serum albumin (DNP-HSA) by human dendritic cells (DC) cultured with granulocyte-macrophage colony-stimulating factor (GM-CSF) and interleukin-4 (IL-4) was studied. It has been shown that the amount of uncomplexed or IgG-complexed antigen required by DC to start an immune response is low compared with other antigen-presenting cells. We therefore examined whether such efficient presentation of immune complexes is due to an enhanced Fc gamma RII-mediated endocytosis or to a specialized and efficient antigen handling, i.e., macropinocytosis. The Fc gamma RII expression was found to be heterogeneous on the GM-CSF- and IL-4-cultured DC, i.e. it ranges from low to high expression. The handling of antigen and immune complexes revealed, that the level of binding and uptake of IgG-DNP-HSA complexes by in vitro expanded DC is low compared with free antigen. Uncomplexed DNP-HSA is probably handled either by endocytosis via receptors being more abundant and/or efficient than the Fc gamma RII or via non-receptor-mediated endocytosis. The binding and uptake of IgG-complexed DNP-HSA was blocked by anti-Fc gamma RII antibody, indicating the specificity of the interaction.
authors.affiliation: Department of Clinical Microbiology, Faculty of Health Sciences, Linköping University, Sweden.
authors.forename: M
authors.initials: M
authors.lastname: Larsson
authors.forename: J
authors.initials: J
authors.lastname: Berge
authors.forename: A G
authors.initials: AG
authors.lastname: Johansson
authors.forename: U
authors.initials: U
authors.lastname: Forsum
mesh_terms: D000936:Antigen-Antibody Complex / Q000276:immunology*; D001667:Binding, Competitive; D018929:Cell Culture Techniques; D003713:Dendritic Cells / Q000276:immunology*; D004140:Dinitrophenols / Q000276:immunology*; D004705:Endocytosis; D005434:Flow Cytometry; D006801:Humans; D007074:Immunoglobulin G / Q000276:immunology*; D016130:Immunophenotyping; D007728:Kupffer Cells / Q000276:immunology; D017452:Receptors, IgG / Q000276:immunology; D012709:Serum Albumin / Q000276:immunology*; D013696:Temperature
chemical_list: D000936:Antigen-Antibody Complex; D004140:Dinitrophenols; D007074:Immunoglobulin G; D017452:Receptors, IgG; D012709:Serum Albumin; C058064:dinitrophenyl-human serum albumin conjugate