Checkpoint blockade immunotherapy induces dynamic changes in PD-1-CD8+ tumor-infiltrating T cells

An improved understanding of the anti-tumor CD8+ T cell response after checkpoint blockade would enable more informed and effective therapeutic strategies. Here we examined the dynamics of the effector response of CD8+ tumor-infiltrating lymphocytes (TILs) after checkpoint blockade therapy. Bulk and single-cell RNA profiles of CD8+ TILs after combined Tim-3+PD-1 blockade in preclinical models revealed significant changes in the transcriptional profile of PD-1? TILs. These cells could be divided into subsets bearing characterstics of naive-, effector-, and memory-precursor-like cells. Effector- and memory-precursor-like TILs contained tumor-antigen-specific cells, exhibited proliferative and effector capacity, and expanded in response to different checkpoint blockade therapies across different tumor models. The memory-precursor-like subset shared features with CD8+ T cells associated with response to checkpoint blockade in patients and was compromised in the absence of Tcf7. Expression of Tcf7 was requisite for the efficacy of diverse immunotherapies, highlighting the importance of this transcriptional regulator in the development of effective CD8+ T cell responses upon immunotherapy. Overall design: (i) RNAseq of Wild Type Naïve-like, Memory-like and Effector-like subpopulations of PD1-CD8+ Tumor infiltrating lymphocytes isolated from MC38-OVA. CD62LhiSlamf7-CX3CR1-, CD62L-Slamf7hiCX3CR1- and CD62L-Slamf7hiCX3CR1+ subsets within PD-1-CD8+ TILs (ii) RNAseq from WT mice, Tim-3+PD-1+ and Tim-3-PD-1- CD8+ TILs were isolated by cell sorting from MC38-OVA tumor-bearing mice that were treated with anti-PD-1 and anti-Tim-3 antibodies or isotype controls. (iii) Droplet-based single-cell RNA-Seq of Tim-3-PD-1- CD8+ TILs from MC38-OVA tumor-bearing WT mice that were treated with anti-PD-1 and anti-Tim-3 antibodies or isotype controls.

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Kurtulus S, Madi A, Escobar G, Klapholz M, Nyman J, Christian E, Pawlak M, Dionne D, Xia J, Rozenblatt-Rosen O, Kuchroo VK, Regev A, Anderson AC