title: IL-4-producing CD4+ T cells in reactive lymph nodes during helminth infection are T follicular helper cells.
abstract: Interleukin (IL)-4 is the quintessential T helper type 2 (Th2) cytokine produced by CD4(+) T cells in response to helminth infection. IL-4 not only promotes the differentiation of Th2 cells but is also critical for immunoglobulin (Ig) G1 and IgE isotype-switched antibody responses. Despite the IL-4-mediated link between Th2 cells and B lymphocytes, the location of IL-4-producing T cells in the lymph nodes is currently unclear. Using IL-4 dual reporter mice, we examined the Th2 response and IL-4 production in the draining mesenteric lymph nodes during infection with the enteric nematode Heligmosomoides polygyrus. We show that although IL-4-competent Th2 cells are found throughout the B and T cell areas, IL-4-producing Th2 cells are restricted to the B cell follicles and associate with germinal centers. Consistent with their localization, IL-4 producers express high levels of CXCR5, ICOS, PD-1, IL-21, and BCL-6, a phenotype characteristic of T follicular helper (Tfh) cells. Although IL-4 was dispensable for the generation of Th2 and Tfh cells, its deletion resulted in defective B cell expansion and maturation. Our report reveals the compartmentalization of Th2 priming and IL-4 production in the lymph nodes during infection, and identifies Tfh cells as the dominant source of IL-4 in vivo.
authors.affiliation: Trudeau Institute, Saranac Lake, NY 12983, USA.
authors.forename: Irah L
authors.initials: IL
authors.lastname: King
authors.forename: Markus
authors.initials: M
authors.lastname: Mohrs
mesh_terms: D000818:Animals; D000917:Antibody Formation; D001402:B-Lymphocytes / Q000276:immunology; D015704:CD4 Antigens / Q000276:immunology; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology*; D006373:Helminthiasis / Q000276:immunology*; D007073:Immunoglobulin E / Q000276:immunology; D007074:Immunoglobulin G / Q000276:immunology; D015847:Interleukin-4 / Q000235:genetics / Q000276:immunology*; D008198:Lymph Nodes / Q000276:immunology*; D051379:Mice; D012333:RNA, Messenger / Q000235:genetics; D013601:T-Lymphocytes / Q000276:immunology*; D018418:Th2 Cells / Q000276:immunology; D014158:Transcription, Genetic
chemical_list: D015704:CD4 Antigens; D007074:Immunoglobulin G; D012333:RNA, Messenger; D015847:Interleukin-4; D007073:Immunoglobulin E