Blockade of the immunosuppressive KIR2DL5/PVR pathway elicits potent human NK cell–mediated antitumor immunity
Xiaoxin Ren, … , Deyou Zheng, Xingxing Zang
Xiaoxin Ren, … , Deyou Zheng, Xingxing Zang
Published November 15, 2022
Citation Information: J Clin Invest. 2022;132(22):e163620. https://doi.org/10.1172/JCI163620.
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Research Article Immunology Oncology

Blockade of the immunosuppressive KIR2DL5/PVR pathway elicits potent human NK cell–mediated antitumor immunity

Abstract

Cancer immunotherapy targeting the TIGIT/PVR pathway is currently facing challenges. KIR2DL5, a member of the human killer cell, immunoglobulin-like receptor (KIR) family, has recently been identified as another binding partner for PVR. The biology and therapeutic potential of the KIR2DL5/PVR pathway are largely unknown. Here we report that KIR2DL5 was predominantly expressed on human NK cells with mature phenotype and cytolytic function and that it bound to PVR without competition with the other 3 known PVR receptors. The interaction between KIR2DL5 on NK cells and PVR on target cells induced inhibitory synapse formation, whereas new monoclonal antibodies blocking the KIR2DL5-PVR interaction robustly augmented the NK cytotoxicity against PVR+ human tumors. Mechanistically, both intracellular ITIM and ITSM of KIR2DL5 underwent tyrosine phosphorylation after engagement, which was essential for KIR2DL5-mediated NK suppression by recruiting SHP-1 and/or SHP-2. Subsequently, ITIM/SHP-1/SHP-2 and ITSM/SHP-1 downregulated the downstream Vav1/ERK1/2/p90RSK/NF-κB signaling. KIR2DL5+ immune cells infiltrated in various types of PVR+ human cancers. Markedly, the KIR2DL5 blockade reduced tumor growth and improved overall survival across multiple NK cell–based humanized tumor models. Thus, our results revealed functional mechanisms of KIR2DL5-mediated NK cell immune evasion, demonstrated blockade of the KIR2DL5/PVR axis as a therapy for human cancers, and provided an underlying mechanism for the clinical failure of anti-TIGIT therapies.

Authors

Xiaoxin Ren, Mou Peng, Peng Xing, Yao Wei, Phillip M. Galbo Jr., Devin Corrigan, Hao Wang, Yingzhen Su, Xiaoshen Dong, Qizhe Sun, Yixian Li, Xiaoyu Zhang, Winfried Edelmann, Deyou Zheng, Xingxing Zang

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Figure 5

KIR2DL5 ITIM and ITSM mediated NK cell inhibition and suppressed downstream signaling.

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KIR2DL5 ITIM and ITSM mediated NK cell inhibition and suppressed downstr...
(A) Tyrosine (Y) in ITIM and ITSM of KIR2DL5 was mutated to phenylalanine (F). The KIR2DL5– primary NK cells were transduced with WT KIR2DL5 or the indicated mutants, and then examined for protein expression with F8B30 (open) or mIgG1 (shaded). NC, negative control. Data are representative of 2 independent experiments. (B and C) Transduced primary NK cells were treated with (+) or without (–) pervanadate (VO4) for 5 minutes. Cell lysates were immunoprecipitated with anti-KIR2DL5 antibodies. Phospho-tyrosine (4G10), SHP-1, SHP-2, and total KIR2DL5 were detected by immunoblots (B). Quantification of p-Tyr, SHP-1, and SHP-2 association with WT or mutant KIR2DL5 in VO4-treated NK cells (C). WCL, whole-cell lysates. (D) Representative imaging of cell conjugates acquired upon the indicated transduced primary NK and PVR/Raji cell contact followed by staining with anti-KIR2DL5 mAb and DAPI. Scale bars: 10 μm. (E) Lysis of scramble control or PVRKO A427 (top) and Jurkat (bottom) by WT or mutant KIR2DL5–transduced primary NK cells at the indicated E/T ratios. Data are mean for duplicate measurements and representative of 3 independent experiments with 3 different donors. (F and G) Expression and phosphorylation of Vav1, ERK1/2, p90RSK, and NF-κB in sorted KIR2DL5+ primary NK cells after cross-linking with indicated mAbs at indicated time points (F). Quantification of immunoblotting (G). GαM, goat anti–mouse IgG antibody. Data are mean ± SEM from 2 independent experiments. In A, B, and F, data are representative of 3 independent experiments. *P < 0.05, **P < 0.01, ***P < 0.001, ****P < 0.0001, by 1-way ANOVA (C), paired (D) or unpaired Student’s t test (G).