Dendritic cells interact directly with naive B lymphocytes to transfer antigen and initiate class switching in a primary T-dependent response.
Dendritic cells (DC) are thought to initiate Ab synthesis by activation of T cells, which then provide cytokine and cell-bound "help" to B cells. Here, we provide evidence that DC can capture and retain unprocessed Ag in vitro and in vivo, and can transfer this Ag to naive B cells to initiate a specific Ab response. The response is skewed with 4- to 13-fold higher titers of IgG than IgM, and the predominant subclasses of Ab produced in naive animals are those associated with Th2-type responses. Ag retention and the skew in class switching is a physiologic phenomenon because DC loaded with Ag in vivo and isolated 24 h later initiated a class-switched, Ag-specific Ab response in naive animals. In vitro studies confirmed that DC provide naive B cells with signals that are essential for the synthesis of class-switched Ab. Taken together, these observations show that DC have an important role in the initiation of Ab synthesis by direct interaction with B cells.
Sir William Dunn School of Pathology, University of Oxford, United Kingdom. michelle.wykes@pathology.ox.ac.uk
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D000818:Animals; D000941:Antigens / Q000378:metabolism*; D001402:B-Lymphocytes / Q000276:immunology* / Q000378:metabolism; D002450:Cell Communication / Q000276:immunology*; D003713:Dendritic Cells / Q000276:immunology* / Q000637:transplantation; D016650:Fluorescein-5-isothiocyanate / Q000378:metabolism; D006433:Hemocyanins / Q000276:immunology; D006735:Horseradish Peroxidase / Q000276:immunology / Q000378:metabolism; D017578:Immunoglobulin Class Switching; D007074:Immunoglobulin G / Q000096:biosynthesis; D007399:Interphase / Q000276:immunology; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D012709:Serum Albumin / Q000276:immunology / Q000378:metabolism; D013601:T-Lymphocytes / Q000276:immunology*
C042158:2,4-dinitrophenyl keyhole limpet hemocyanin; D000941:Antigens; D007074:Immunoglobulin G; D012709:Serum Albumin; D006433:Hemocyanins; D006735:Horseradish Peroxidase; D016650:Fluorescein-5-isothiocyanate