Abstract
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.
Publication types
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Research Support, N.I.H., Extramural
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Research Support, Non-U.S. Gov't
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Review
MeSH terms
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Animals
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CD4-Positive T-Lymphocytes / cytology
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CD4-Positive T-Lymphocytes / immunology
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CD4-Positive T-Lymphocytes / metabolism
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Cell Differentiation / immunology
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Cell Differentiation / physiology
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Cell Lineage / immunology*
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Humans
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Inflammation / immunology
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Inflammation / metabolism
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Interleukin-17 / biosynthesis
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Interleukin-17 / physiology
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Interleukin-23
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Interleukin-23 Subunit p19
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Interleukins / biosynthesis
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Interleukins / physiology
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Models, Immunological
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T-Lymphocyte Subsets / cytology*
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T-Lymphocyte Subsets / immunology
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T-Lymphocyte Subsets / metabolism
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T-Lymphocytes, Helper-Inducer / cytology*
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T-Lymphocytes, Helper-Inducer / immunology
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T-Lymphocytes, Helper-Inducer / metabolism
Substances
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IL23A protein, human
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Interleukin-17
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Interleukin-23
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Interleukin-23 Subunit p19
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Interleukins