A transcriptionally and functionally distinct PD-1+ CD8+ T cell pool with predictive potential in non-small-cell lung cancer treated with PD-1 blockade

Abstract

Evidence from mouse chronic viral infection models suggests that CD8+ T cell subsets characterized by distinct expression levels of the receptor PD-1 diverge in their state of exhaustion and potential for reinvigoration by PD-1 blockade. However, it remains unknown whether T cells in human cancer adopt a similar spectrum of exhausted states based on PD-1 expression levels. We compared transcriptional, metabolic, and functional signatures of intratumoral CD8+ T lymphocyte populations with high (PD-1T), intermediate (PD-1N) and no PD-1 expression (PD-1-) from non-small cell lung cancer patients. We observed that, PD-1T T cells show a markedly different transcriptional and metabolic profile as compared to PD-1N and PD-1- lymphocytes, as well as an intrinsically high capacity for tumor recognition. Furthermore, while PD-1T lymphocytes are impaired in classical effector cytokine production, they produce CXCL13 that mediates immune cell recruitment to tertiary lymphoid structures. Strikingly, the presence of PD-1T cells was strongly predictive for both response and survival in a small cohort of non-small cell lung cancer patients treated with PD-1 blockade. The characterization of a distinct state of tumor-reactive, PD-1 bright lymphocytes in human cancer, which only partially resembles that seen in chronic infection, provides novel potential avenues for therapeutic intervention.

A Reproducible, Objective Method Using MitoTracker® Fluorescent Dyes to Assess Mitochondrial Mass in T Cells by Flow Cytometry

“…Although we have focused on MitoTracker® dyes in this report, objective gating could be used to gate populations stained with other mitochondrial dyes, and with other fluorescent antibodies or cellular dyes where delineating “high” and “low” populations is challenging. For example, multiple studies have reported differences in function and response to immunotherapy between PD‐1 “high” and PD‐1 “intermediate” or “low” T cells, but as yet there is no standardized method for identifying these different populations . As we have demonstrated, the method can be modified to gate, for example, cells in the top 50% of the fluorescence range, according to the requirements of the researcher.…”

4‐1BB Delineates Distinct Activation Status of Exhausted Tumor‐Infiltrating CD8+ T Cells in Hepatocellular Carcinoma

“…Another interesting finding is that 4‐1BB was almost exclusively expressed on PD‐1 high CD8 + TILs, which reportedly represent highly exhausted and tumor‐reactive CD8 + TILs . We recently demonstrated that PD‐1 high CD8 + TILs exhibit features of more progressed T‐cell exhaustion compared to PD‐1 int and PD‐1 neg CD8 + TILs and that HCCs with higher proportions of PD‐1 high CD8 + TILs are enriched for the T‐cell–inflamed gene signature .…”

“…We recently demonstrated that PD‐1 + CD8 + TILs from HCC patients can be subdivided into PD‐1 int and PD‐1 high CD8 + TILs and that the latter group shows features of more‐severe T‐cell exhaustion . Another recent study found that PD‐1 high CD8 + TILs exhibit high tumor reactivity . Therefore, we next examined 4‐1BB expression on CD8 + TILs according to differential PD‐1 expression, to investigate the role of 4‐1BB in the context of T‐cell exhaustion and tumor reactivity.…”

“…Exhausted CD8 + T cells are considered a primary target for therapeutic interventions involving ICIs . Therefore, the delineation of distinct features of exhausted CD8 + TILs based on T‐cell activation status could help direct therapeutic strategies to maximize CD8 + TIL activation and assess the degree of preexisting T‐cell activation that can be targeted by immunotherapy.…”

“…We recently demonstrated that PD‐1 high CD8 + TILs exhibit features of more progressed T‐cell exhaustion compared to PD‐1 int and PD‐1 neg CD8 + TILs and that HCCs with higher proportions of PD‐1 high CD8 + TILs are enriched for the T‐cell–inflamed gene signature . Similarly, Thommen et al examined patients with non‐small‐cell lung cancer displaying typical phenotypic features of T‐cell exhaustion and reported that PD‐1 high CD8 + TILs were associated with higher tumor recognition capacity and response to anti–PD‐1 therapy . These findings suggest that PD‐1 high CD8 + TILs indicate active engagement against tumors and resultant exhausted phenotypes.…”