Rho Hyun Seong

T cell‐mediated antitumor immunity is modulated, in part, by N‐glycosylation. However, the interplay between N‐glycosylation and the loss of effector function in exhausted T cells has not yet been fully investigated. Here, we delineated the impact of N‐glycosylation on the exhaustion of tumor‐infiltrating lymphocytes in a murine colon adenocarcinoma model, focusing on the IFN‐γ‐mediated immune response. We found that exhausted CD8 + T cells downregulated the oligosaccharyltransferase complex, which is indispensable for N‐glycan transfer. Concordant N‐glycosylation deficiency in tumor‐infiltrating lymphocytes leads to loss of antitumor immunity. Complementing the oligosaccharyltransferase complex restored IFN‐γ production and alleviated CD8 + T cell exhaustion, resulting in reduced tumor growth. Thus, aberrant glycosylation induced in the tumor microenvironment incapacitates effector CD8 + T cells. Our findings provide insights into CD8 + T cell exhaustion by incorporating N‐glycosylation to understand the characteristic loss of IFN‐γ, opening new opportunities to amend the glycosylation status in cancer immunotherapies.