Programmed death-1 receptor suppresses ?-IFN producing NKT cells in human tuberculosis - 15/05/14
Summary |
IFN-γ biased Th1 effector immune response is crucial for containment of Mycobacterium tuberculosis infection. Various T cell subsets with regulatory function dictate the generation of Th1 like cells. NKT cells are a specialized T cell subset known to be activated early in immune response and control T cell response via release of immunoregulatory cytokines like IFN-γ, IL-4 and IL-10. M. tuberculosis, with abundance of its cell wall lipids may potently activate NKT cells resulting in cytokine production and PD-1 expression. In this study, among 49 treatment naive active pulmonary tuberculosis patients, we found a higher percentage of PD1+ NKT cells correlating with sputum bacillary load. Furthermore, blocking PD-1 increased the number of IFN-γ producing NKT cells by inhibiting their apoptosis. Moreover, peripheral frequency of NKT cells declined with therapy suggesting their role in host T cell response. In this study, we concluded that PD-1 preferentially induces apoptosis of IFN-γ producing NKT cells while sparing NKT cells that produce IL-4. Such a polarized NKT cell function may impose a Th2 bias on the ensuing effector T cell response leading to inefficient clearance of M. tuberculosis. Inhibiting PD-1 may therefore alter the T cell response in favor of the host by rescuing type 1 NKT cells from apoptosis and boosting Th1 effector T cell functions against M. tuberculosis.
Le texte complet de cet article est disponible en PDF.Keywords : Programmed death-1, Natural killer T cell, T helper-1, Effector T cells, Inteferon-gamma
Abbreviations : APCs, ATD, Ag, Cat-I, Cat-II, HCs, IFN-γ, IL-2, Mtb., mAB, MDR-TB, NS, NKT, PBLs, PBMCs, PD-1, PD-L1, PD-L2, PTB, TB, Teff, Th-1, Th-2, WCL
Plan
Vol 94 - N° 3
P. 197-206 - mai 2014 Retour au numéroBienvenue sur EM-consulte, la référence des professionnels de santé.
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