mTORC1 and mTORC2 selectively regulate CD8+ T cell differentiation
Kristen N. Pollizzi, … , Greg M. Delgoffe, Jonathan D. Powell
Kristen N. Pollizzi, … , Greg M. Delgoffe, Jonathan D. Powell
Published April 20, 2015
Citation Information: J Clin Invest. 2015;125(5):2090-2108. https://doi.org/10.1172/JCI77746.
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Research Article Immunology

mTORC1 and mTORC2 selectively regulate CD8+ T cell differentiation

Abstract

Activation of mTOR-dependent pathways regulates the specification and differentiation of CD4+ T effector cell subsets. Herein, we show that mTOR complex 1 (mTORC1) and mTORC2 have distinct roles in the generation of CD8+ T cell effector and memory populations. Evaluation of mice with a T cell–specific deletion of the gene encoding the negative regulator of mTORC1, tuberous sclerosis complex 2 (TSC2), resulted in the generation of highly glycolytic and potent effector CD8+ T cells; however, due to constitutive mTORC1 activation, these cells retained a terminally differentiated effector phenotype and were incapable of transitioning into a memory state. In contrast, CD8+ T cells deficient in mTORC1 activity due to loss of RAS homolog enriched in brain (RHEB) failed to differentiate into effector cells but retained memory characteristics, such as surface marker expression, a lower metabolic rate, and increased longevity. However, these RHEB-deficient memory-like T cells failed to generate recall responses as the result of metabolic defects. While mTORC1 influenced CD8+ T cell effector responses, mTORC2 activity regulated CD8+ T cell memory. mTORC2 inhibition resulted in metabolic reprogramming, which enhanced the generation of CD8+ memory cells. Overall, these results define specific roles for mTORC1 and mTORC2 that link metabolism and CD8+ T cell effector and memory generation and suggest that these functions have the potential to be targeted for enhancing vaccine efficacy and antitumor immunity.

Authors

Kristen N. Pollizzi, Chirag H. Patel, Im-Hong Sun, Min-Hee Oh, Adam T. Waickman, Jiayu Wen, Greg M. Delgoffe, Jonathan D. Powell

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Figure 2

mTORC1 activity is required to promote CD8+ effector T cell responses in vitro.

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mTORC1 activity is required to promote CD8+ effector T cell responses in...
(A) mTORC1 activity was assessed by flow cytometric analysis of phosphorylated S6S235/236 expression from WT, T-Tsc2–/–, and T-Rheb–/– purified CD8+ T cells stimulated (+S) for 48 hours with αCD3/αCD28 compared with unstimulated WT controls (WT NS). The mean fluorescence intensity (MFI) for each genotype is shown in the upper corner. (B) Purified CD8+ T cells were collected from WT, T-Rheb–/–, or T-Tsc2–/– mice. mTORC2 activity was assessed by immunoblot analysis from unstimulated cells or after 1.5-hour stimulation with αCD3/αCD28. (C) Splenocytes were stimulated in vitro with αCD3 for 48 hours and then expanded in media supplemented with IL-2 for 5 days. On day 5, cells were restimulated and intracellular production of IFN-γ, TNF-α, and granzyme B (GzmB) was measured by flow cytometry. Plots are gated from the CD8+ population. (D) Cytokine production and (E) CFSE dilution were determined from purified naive CD8+ WT and T-Tsc2–/– CD8+ T cells stimulated in vitro. Plots were gated from the CD8+ population. CFSE expression was measured 48 hours after stimulation. Nonstimulated controls shown as gray histograms. (F) As in C, CD127 expression of the CD8+ population was assessed by flow cytometry prior to restimulation. Data are representative of at least 3 independent experiments.