title: The induction of antibody production by IL-6 is indirectly mediated by IL-21 produced by CD4+ T cells.
abstract: Interleukin (IL) 6 is a proinflammtory cytokine produced by antigen-presenting cells and nonhematopoietic cells in response to external stimuli. It was initially identified as a B cell growth factor and inducer of plasma cell differentiation in vitro and plays an important role in antibody production and class switching in vivo. However, it is not clear whether IL-6 directly affects B cells or acts through other mechanisms. We show that IL-6 is sufficient and necessary to induce IL-21 production by naive and memory CD4(+) T cells upon T cell receptor stimulation. IL-21 production by CD4(+) T cells is required for IL-6 to promote B cell antibody production in vitro. Moreover, administration of IL-6 with inactive influenza virus enhances virus-specific antibody production, and importantly, this effect is dependent on IL-21. Thus, IL-6 promotes antibody production by promoting the B cell helper capabilities of CD4(+) T cells through increased IL-21 production. IL-6 could therefore be a potential coadjuvant to enhance humoral immunity.
authors.affiliation: Department of Medicine/Immunobiology Program, University of Vermont, Burlington, VT 05405, USA.
authors.forename: Oliver
authors.initials: O
authors.lastname: Dienz
authors.forename: Sheri M
authors.initials: SM
authors.lastname: Eaton
authors.forename: Jeffrey P
authors.initials: JP
authors.lastname: Bond
authors.forename: Wendy
authors.initials: W
authors.lastname: Neveu
authors.forename: David
authors.initials: D
authors.lastname: Moquin
authors.forename: Rajkumar
authors.initials: R
authors.lastname: Noubade
authors.forename: Eva M
authors.initials: EM
authors.lastname: Briso
authors.forename: Colette
authors.initials: C
authors.lastname: Charland
authors.forename: Warren J
authors.initials: WJ
authors.lastname: Leonard
authors.forename: Gennaro
authors.initials: G
authors.lastname: Ciliberto
authors.forename: Cory
authors.initials: C
authors.lastname: Teuscher
authors.forename: Laura
authors.initials: L
authors.lastname: Haynes
authors.forename: Mercedes
authors.initials: M
authors.lastname: Rincon
mesh_terms: D000818:Animals; D000914:Antibodies, Viral / Q000097:blood / Q000276:immunology; D000917:Antibody Formation / Q000187:drug effects / Q000502:physiology*; D001402:B-Lymphocytes / Q000187:drug effects / Q000378:metabolism; D015496:CD4-Positive T-Lymphocytes / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D016207:Cytokines / Q000235:genetics / Q000378:metabolism / Q000494:pharmacology; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D015870:Gene Expression; D007074:Immunoglobulin G / Q000097:blood / Q000378:metabolism; D007075:Immunoglobulin M / Q000097:blood / Q000276:immunology; D015850:Interleukin-6 / Q000235:genetics / Q000494:pharmacology / Q000502:physiology*; D053698:Interleukin-6 Receptor alpha Subunit / Q000378:metabolism; D007378:Interleukins / Q000235:genetics / Q000378:metabolism* / Q000494:pharmacology; D008213:Lymphocyte Activation / Q000187:drug effects; D051379:Mice; D008810:Mice, Inbred C57BL; D008815:Mice, Inbred Strains; D018345:Mice, Knockout; D008822:Mice, Transgenic; D009975:Orthomyxoviridae / Q000276:immunology; D011948:Receptors, Antigen, T-Cell / Q000378:metabolism; D053655:Receptors, Interleukin-21 / Q000235:genetics / Q000378:metabolism; D000098546:Interleukin-21
chemical_list: D000914:Antibodies, Viral; D016207:Cytokines; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D015850:Interleukin-6; D053698:Interleukin-6 Receptor alpha Subunit; D007378:Interleukins; D011948:Receptors, Antigen, T-Cell; D053655:Receptors, Interleukin-21; D000098546:Interleukin-21