title: Follicular Helper T Cells.
abstract: Although T cell help for B cells was described several decades ago, it was the identification of CXCR5 expression by B follicular helper T (Tfh) cells and the subsequent discovery of their dependence on BCL6 that led to the recognition of Tfh cells as an independent helper subset and accelerated the pace of discovery. More than 20 transcription factors, together with RNA-binding proteins and microRNAs, control the expression of chemotactic receptors and molecules important for the function and homeostasis of Tfh cells. Tfh cells prime B cells to initiate extrafollicular and germinal center antibody responses and are crucial for affinity maturation and maintenance of humoral memory. In addition to the roles that Tfh cells have in antimicrobial defense, in cancer, and as HIV reservoirs, regulation of these cells is critical to prevent autoimmunity. The realization that follicular T cells are heterogeneous, comprising helper and regulatory subsets, has raised questions regarding a possible division of labor in germinal center B cell selection and elimination.
authors.affiliation: Department of Immunology and Infectious Disease, John Curtin School of Medical Research, Australian National University, Canberra, ACT 2601, Australia; email: carola.vinuesa@anu.edu.au.
authors.forename: Carola G
authors.initials: CG
authors.lastname: Vinuesa
authors.affiliation: Lymphocyte Signalling and Development Institute Strategic Programme, Babraham Institute, Cambridge CB22 3AT, United Kingdom; email: michelle.linterman@babraham.ac.uk.
authors.forename: Michelle A
authors.initials: MA
authors.lastname: Linterman
authors.affiliation: Laboratory for Molecular Immunomodulation, Department of Biochemistry and Molecular Biology, and Center for Inflammatory Diseases, Monash University, Melbourne, Victoria 3800, Australia; email: di.yu@monash.edu.
authors.forename: Di
authors.initials: D
authors.lastname: Yu
authors.affiliation: School of Immunity and Infection, University of Birmingham, Birmingham B15 2TT, United Kingdom.
authors.forename: Ian C M
authors.initials: IC
authors.lastname: MacLennan
mesh_terms: D000818:Animals; D001402:B-Lymphocytes / Q000276:immunology*; D002454:Cell Differentiation; D005786:Gene Expression Regulation; D018858:Germinal Center / Q000276:immunology*; D006801:Humans; D056724:Immunity, Humoral; D007156:Immunologic Memory; D008213:Lymphocyte Activation; D035683:MicroRNAs / Q000235:genetics; D051560:Proto-Oncogene Proteins c-bcl-6 / Q000378:metabolism; D054380:Receptors, CXCR5 / Q000378:metabolism; D016176:T-Lymphocyte Subsets / Q000276:immunology*; D006377:T-Lymphocytes, Helper-Inducer / Q000276:immunology*
chemical_list: C084103:BCL6 protein, human; D035683:MicroRNAs; D051560:Proto-Oncogene Proteins c-bcl-6; D054380:Receptors, CXCR5
keywords: B follicular helper T (Tfh) cell; antibody responses; germinal center