mTOR signaling promotes a robust and continuous production of IFN‐γ by human memory CD8+ T cells and their proliferation |
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| Authors: | Ruka Setoguchi Yui Matsui Kousuke Mouri |
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| Affiliation: | Center for Innovation in Immunoregulative Technology and Therapeutics, Graduate School of Medicine, Kyoto University, Kyoto, Japan |
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| Abstract: | Human CD8+ T cells are functionally heterogeneous and can be divided into phenotypically and functionally distinct subsets according to CCR7 and CD45RA expression levels. Among these, CCR7lowCD45RAlow effector memory CD8+ T cells (Tem) and CCR7lowCD45RAhigh CD8+ T cells, which are designated as Temra and considered to be terminally differentiated cells, are Ag‐experienced T cells but show different functionalities. Here, we show that, while Tem proliferate vigorously and produce IFN‐γ persistently and robustly, Temra proliferate poorly and lose the ability to produce IFN‐γ over time after TCR stimulation. Temra showed impaired cell growth upon TCR stimulation, which was associated with defective activation of the mammalian target of rapamycin (mTOR) signaling. Furthermore, rapamycin, an inhibitor of mTOR signaling, interfered with the robust and continuous proliferation of and IFN‐γ production by Tem at later time points after TCR stimulation. Thus, these data collectively indicate that activation of mTOR signaling is required for the robust functions of Tem cells in humans and suggest that defective mTOR signaling in Temra contributes to their functional impairment. |
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| Keywords: | CCR7 CD45RA CD8+ T cells IFN‐γ mTOR signaling |
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