SHP-1 phosphatase activity counteracts increased T cell receptor affinity
Michael Hebeisen, … , Daniel E. Speiser, Nathalie Rufer
Michael Hebeisen, … , Daniel E. Speiser, Nathalie Rufer
Published February 8, 2013
Citation Information: J Clin Invest. 2013;123(3):1044-1056. https://doi.org/10.1172/JCI65325.
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SHP-1 phosphatase activity counteracts increased T cell receptor affinity

Abstract

Anti-self/tumor T cell function can be improved by increasing TCR-peptide MHC (pMHC) affinity within physiological limits, but paradoxically further increases (Kd < 1 μM) lead to drastic functional declines. Using human CD8+ T cells engineered with TCRs of incremental affinity for the tumor antigen HLA-A2/NY-ESO-1, we investigated the molecular mechanisms underlying this high-affinity–associated loss of function. As compared with cells expressing TCR affinities generating optimal function (Kd = 5 to 1 μM), those with supraphysiological affinity (Kd = 1 μM to 15 nM) showed impaired gene expression, signaling, and surface expression of activatory/costimulatory receptors. Preferential expression of the inhibitory receptor programmed cell death-1 (PD-1) was limited to T cells with the highest TCR affinity, correlating with full functional recovery upon PD-1 ligand 1 (PD-L1) blockade. In contrast, upregulation of the Src homology 2 domain-containing phosphatase 1 (SHP-1/PTPN6) was broad, with gradually enhanced expression in CD8+ T cells with increasing TCR affinities. Consequently, pharmacological inhibition of SHP-1 with sodium stibogluconate augmented the function of all engineered T cells, and this correlated with the TCR affinity–dependent levels of SHP-1. These data highlight an unexpected and global role of SHP-1 in regulating CD8+ T cell activation and responsiveness and support the development of therapies inhibiting protein tyrosine phosphatases to enhance T cell–mediated immunity.

Authors

Michael Hebeisen, Lukas Baitsch, Danilo Presotto, Petra Baumgaertner, Pedro Romero, Olivier Michielin, Daniel E. Speiser, Nathalie Rufer

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Figure 7

Pharmacological inhibition of SHP-1 phosphatase in TCR engineered CD8+ T cells.

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Pharmacological inhibition of SHP-1 phosphatase in TCR engineered CD8+ T...
(A) Representative histograms of the levels (in MFI) of LAMP-1/CD107a expression in TCR-transduced CD8+ T cells without (control, blue histograms) or with SHP-1 inhibition by SSG (red histograms) prior to 4 hour stimulation with 10 μM NY-ESO-1157–165–loaded T2 cells. CD107a degranulation following stimulation with unloaded T2 cells is depicted as gray histograms. Graphs below each respective histogram represent the direct comparison of TCR stimulation–associated CD107a levels without (–) or with SHP-1 inhibition (+). Paired 2-tailed t test; ***P < 0.001; **P < 0.01; *P < 0.05. Data were obtained from 6 independent experiments. (B) Relative CD107a degranulation ratio (in gMFI) obtained in the presence versus the absence of the SHP-1 inhibitor SSG. Graphs show relative CD107 fold increase following stimulation with unloaded (left panel) or NY-ESO-1–pulsed (right panel) T2 cells. (C) Melanoma cell killing by TCR-transduced CD8+ T cells without (mock) or with SSG treatment for 4 days. Tumor reactivity for the melanoma cell line Me 275 was assessed in a functional 4-hour 51Cr release assay. (D) Relative 51Cr cpm ratio with and without SSG at the indicated E:T ratios. Unpaired 2-tailed t test; ***P < 0.001; **P < 0.01; *P < 0.05.