Follicular Helper strongTstrong Cells Lineage and Location.pdf

Immunity Review Follicular Helper T Cells: Lineage and Location Nicolas Fazilleau,1 Linda Mark,1 Louise J. McHeyzer-Williams,1 and Michael G. McHeyzer-Williams1,* 1Department of Immunology and Microbial Sciences, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA *Correspondence: mcheyzer@ DOI 10.1016/j.immuni.2009.03.003 Follicular helper T (Tfh) cells are the class of effector T helper cells that regulates the step-wise development of antigen-specific B cell immunity in vivo. Deployment of CXCR5+ Tfh cells to B cell zones of lymphoid tissues and stable cognate interactions with B cells are central to the delivery of antigen-specific Tfh cell function. Here, we review recent advances that have helped to unravel distinctive elements of developmental programming for Tfh cells and unique effector Tfh cell functions focused on antigen-primed B cells. Under- standing the regulatory functions of Tfh cells in the germinal center and the subsequent regulation of memory B cell responses to antigen recall represent the frontiers of this research area with the potential to alter funda- mentally the design of future vaccines. Introduction Recent evidence suggests that Tfh cells constitute a separate Clonal selection and the programmed development of antigen- lineage of effector T helper cells with distinct developmental specific immune function are the central defining characteristics programming and distinguishable effector function. There is of adaptive immunity. Classical studies identified the cells of the also evidence to suggest that deployment