CD155/CD96 promotes immunosuppression in lung adenocarcinoma (LUAD)

Lung adenocarcinoma (LUAD) remains one of the leading causes of death in patients with cancer. The association of CD155 with CD96 transmits an inhibitory signal and suppresses antitumor immune response. This study investigates the effect of CD155/CD96 on immune suppression in LUAD. We demonstrate that LUAD patients with high CD155 expression suffer from immune suppression and experience a poor prognosis, which coincides with an inhibited AKT-mTOR signaling pathway in CD8 T cells and subsequently up-regulated CD96 expression. Moreover, the inhibition effect can be reversed by CD96 blocking antibody. High CD155 expression inhibited the release of IFNγ from CD8 cells. Moreover, Blocking CD96 restored IFNγ production in CD8 T cells and neutralized the inhibition of IFNγ production in CD8 T cells mediated by CD155. Animal experiments showed that CD155-mediated LUAD growth might depend on its suppression antitumor immune response in the tumor microenvironment in PDX mice. In conclusion, our results suggest that LUAD cells suppress antitumor immune response in the tumor microenvironment through CD155/CD96. CD155/CD96 could be a potential therapeutic target for LUAD patients. Abbreviations LUAD: lung adenocarcinoma; IFNγ: interferon gamma; PDX: patient-derived xenograft; NSCLC: non-small cell lung cancer; PRR: poliovirus receptor–related; MDSCs: myeloid-derived suppressor cells; PRR: poliovirus receptor–related; STR: short tandem repeat; IRS: immunoreactive score; SI: staining intensity; PP: percentage of positive cells; RT-PCR: reverse transcription-polymerase chain reaction; PBS: phosphate-buffered saline; PBMCs: peripheral blood mononuclear cells; SDS–PAGE: sodium dodecyl sulfate-polyacrylamide gel electrophoresis; rCD155: recombinant human CD155; LUAD cells: lung adenocarcinoma cells; TILs: tumor-infiltrating lymphocytes; GzmB: granzyme B; IL-2 (Interleukin-2); TNF-α : tumor necrosis factor-alpha; PI: propidium Iodide; PDX: patient-derived xenograft; TIGIT: T cell immunoreceptor with Igand ITIM domains; WBC: white blood cells; MFI: mean fluorescence intensity; HPF: high power field