Diversification of T-helper-cell lineages: finding the family root of IL-17-producing cells.
CD4+ T helper 1 (T(H)1) and T(H)2 cells have long been regarded as two sides of a coin in terms of adaptive immune responses. However, as I discuss here, this concept needs to be reconsidered. In particular, recent data indicate that interleukin-17 (IL-17) is produced by T(H) cells that are distinct from the traditional T(H)1- and T(H)2-cell subsets. Furthermore, the generation of these IL-17-producing CD4+ T cells from naive precursors during immune responses is not dependent on the cytokines and transcription factors that mediate T(H)1- and T(H)2-cell development. Given that IL-17 has crucial roles in regulating tissue inflammation and the development of disease in several animal models of autoimmunity, I propose that IL-17-producing CD4+ T cells represent a distinct inflammatory T(H)-cell lineage.
Dong
Chen
C
Department of Immunology, MD Anderson Cancer Center, Houston, Texas 77030, USA. cdong@mdanderson.org
D000818:Animals; D015496:CD4-Positive T-Lymphocytes / Q000166:cytology / Q000276:immunology / Q000378:metabolism; D002454:Cell Differentiation / Q000276:immunology / Q000502:physiology; D019070:Cell Lineage / Q000276:immunology*; D006801:Humans; D007249:Inflammation / Q000276:immunology / Q000378:metabolism; D020381:Interleukin-17 / Q000096:biosynthesis / Q000502:physiology; D053759:Interleukin-23; D053760:Interleukin-23 Subunit p19; D007378:Interleukins / Q000096:biosynthesis / Q000502:physiology; D018448:Models, Immunological; D016176:T-Lymphocyte Subsets / Q000166:cytology* / Q000276:immunology / Q000378:metabolism; D006377:T-Lymphocytes, Helper-Inducer / Q000166:cytology* / Q000276:immunology / Q000378:metabolism
C508840:IL23A protein, human; D020381:Interleukin-17; D053759:Interleukin-23; D053760:Interleukin-23 Subunit p19; D007378:Interleukins