Blood dendritic cells interact with splenic marginal zone B cells to initiate T-independent immune responses.
Marginal zone (MZ) and B1 B lymphocytes participate jointly in the early immune response against T-independent (TI) particulate antigens. Here we show that blood-derived neutrophil granulocytes and CD11c(lo) immature dendritic cells (DC) are the primary cells that efficiently capture and transport particulate bacteria to the spleen. In a systemic infection, CD11c(lo) DC, but not neutrophils, provide critical survival signals, which can be inhibited by TACI-Fc, to antigen-specific MZ B cells and promote their differentiation into IgM-secreting plasmablasts. In a local TI response, peritoneal cavity macrophages provide similar support to B1 B-derived Ag-specific blasts. In the absence of soluble TACI ligands, Ag-activated MZ- and B1-derived blasts lack survival signals and undergo apoptosis, resulting in severely impaired antibody responses.
D019264:Adoptive Transfer; D000818:Animals; D017951:Antigen Presentation / Q000276:immunology*; D000955:Antigens, T-Independent / Q000276:immunology*; D017209:Apoptosis / Q000276:immunology; D016175:B-Lymphocyte Subsets / Q000276:immunology*; D001419:Bacteria / Q000276:immunology; D001773:Blood Cells / Q000276:immunology; D039521:CD11c Antigen / Q000032:analysis; D002454:Cell Differentiation; D002478:Cells, Cultured / Q000276:immunology; D002634:Chemotaxis, Leukocyte; D003713:Dendritic Cells / Q000276:immunology*; D007075:Immunoglobulin M / Q000096:biosynthesis / Q000276:immunology; D007153:Immunologic Deficiency Syndromes / Q000276:immunology; D008213:Lymphocyte Activation / Q000276:immunology; D017737:Macrophages, Peritoneal / Q000276:immunology; D008565:Membrane Proteins; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D008822:Mice, Transgenic; D009504:Neutrophils / Q000276:immunology*; D010950:Plasma Cells / Q000276:immunology; D018124:Receptors, Tumor Necrosis Factor / Q000276:immunology; D013154:Spleen / Q000166:cytology / Q000276:immunology*; D053303:Transmembrane Activator and CAML Interactor Protein
D000955:Antigens, T-Independent; D039521:CD11c Antigen; D007075:Immunoglobulin M; D008565:Membrane Proteins; D018124:Receptors, Tumor Necrosis Factor; C486361:Tnfrsf13b protein, mouse; D053303:Transmembrane Activator and CAML Interactor Protein