T follicular helper (TFH) cells in normal and dysregulated immune responses.
T cell help for antibody production is a fundamental aspect of immune responses. Only recently has a better understanding of the cellular and molecular mechanisms for T cell help emerged. A subset of T cells, termed T follicular helper cells (T(FH) cells), provides a helper function to B cells and represents one of the most numerous and important subsets of effector T cells in lymphoid tissues. T(FH) cells are distinguishable from Th1 and Th2 cells by several criteria, including chemokine receptor expression (CXCR5), location/migration (B cell follicles), and function (B cell help). Central to the function of CD4(+) T cells is IL-21, a "helper" cytokine produced by T(FH) cells that potently stimulates the differentiation of B cells into Ab-forming cells through IL-21R. Consequently, dysregulation of T(FH) cell function, and over- or under-expression of T(FH) cell-associated molecules such as ICOS or IL-21, most likely contributes to the pathogenesis of certain autoimmune diseases or immunodeficiencies.
King
Cecile
C
Immunology and Inflammation Research Program, Garvan Institute of Medical Research, Sydney, NSW 2010, Australia. c.king@garvan.org.au
Tangye
Stuart G
SG
Mackay
Charles R
CR
D000818:Animals; D000917:Antibody Formation / Q000276:immunology*; D018858:Germinal Center / Q000166:cytology / Q000276:immunology*; D006801:Humans; D007154:Immune System Diseases / Q000276:immunology*; D018448:Models, Immunological; D016176:T-Lymphocyte Subsets / Q000166:cytology / Q000276:immunology / Q000378:metabolism; D006377:T-Lymphocytes, Helper-Inducer / Q000166:cytology / Q000276:immunology* / Q000378:metabolism