1. The Role of KLRG1 in Human CD4+ T-Cell Immunity Against Tuberculosis.
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Zhidong Hu, Hui-Min Zhao, Chun-Ling Li, Xu-Hui Liu, Barkan, Daniel, Lowrie, Douglas B., Shui-Hua Lu, Xiao-Yong Fan, Hu, Zhidong, Zhao, Hui-Min, Li, Chun-Ling, Liu, Xu-Hui, Lu, Shui-Hua, and Fan, Xiao-Yong
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KILLER cells , *TUBERCULOSIS -- Immunological aspects , *IMMUNOCOMPETENT cells , *T cells , *CD4 antigen - Abstract
Background: KLRG1 is a marker of terminally differentiated CD8+ T cells in viral infection, but its role in human Mycobacterium tuberculosis infection remains elusive.Methods: A set of cohorts of patients with tuberculosis was designed, and the expression profiles and functions of KLRG1+CD4+ T cells were determined with and without antibody blocking.Results: KLRG1 expression on CD4+ T cells was significantly increased in patients with active tuberculosis, compared with healthy controls and patients without tuberculosis. Upon M. tuberculosis-specific stimulation, the ability to secrete interferon γ, interleukin 2, and tumor necrosis factor α was significantly greater in KLRG1-expressing CD4+ T cells than in their KLRG-negative counterparts and was accompanied by a decreased proportion of regulatory T cells and increased Akt signaling. However, KLRG1-expressing CD4+ T cells had a shorter life-span, which was associated with a higher apoptosis rate but a similar proliferative response. Blockade of KLRG1 signaling significantly enhanced interferon γ and interleukin 2 secretion without affecting either cell apoptosis or multiplication. Addition of a specific Akt inhibitor prevented this increased cytokine response, implicating the Akt signaling pathway.Conclusions: Our study delineated the profile of KLRG1+CD4+ T cells in patients with tuberculosis and suggests that M. tuberculosis infection drives CD4+ T cells to acquire increased effector function in a terminally differentiated state, which is restrained by KLRG1 via KLRG1/Akt signaling pathway. [ABSTRACT FROM AUTHOR]- Published
- 2018
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