Functionally impaired CD103⁺CD39⁺CD8⁺ T cell subsets with immune-suppressive properties infiltrating gastric cancer tissues promote tumor progression

To detect the infiltration level of CD103⁺CD39⁺CD8⁺ T cell subsets in gastric cancer tissues and analyze their response characteristics, clarifying the clinical relevance of this subset.

Surgical specimens (tumor tissues, adjacent tissues, and peripheral blood) were collected from gastric cancer patients at the Department of General Surgery, Second Affiliated Hospital of Army Medical University between January 2023 and May 2024. Flow cytometry and immunofluorescence staining quantified the proportion and number of CD103⁺CD39⁺CD8⁺ T cells in tumor versus adjacent tissues. Flow cytometry further analyzed CD69, PD-1, and IFN-γ expression in this subset. Peripheral blood mononuclear cells (PBMCs) were isolated and cultured in vitro to assess TGF-β1-induce-induced differentiation. Correlation with disease stage was analyzed by detecting the infrltration level of CD103⁺CD39⁺CD8⁺ T Cell subsets via flow cytometry.

Compared with adjacent tissues, gastric cancer tissues showed significantly increased proportions of CD103⁺CD39⁺CD8⁺ T cells (P<0.05); immunofluorescence confirmed higher numbers in tumor tissues. Relative to CD103⁺CD39^- and CD103^-CD39^-CD8⁺ T subsets, CD103⁺ CD39⁺CD8⁺ T cells exhibited elevated CD69 and PD-1 expression (P<0.05) but reduced IFN-γ (P<0.05). In vitro TGF-β1 stimulation upregulated co -expression of CD103 and CD39 in CD8⁺ T cells (P<0.05). Moreover, advanced gastric cancer patients had higher tumor infiltration of this subset than early-stage patients (P<0.05).

CD103⁺CD39⁺CD8⁺ T cell subsets display increased infiltration and functionally impaired responses in gastric cancer, facilitating tumor immune escape.