ABSTRACT
Background: The occurrence of tumor is closely related to the function of immune system. As an effector cell of innate immunity, the function of γδ T cells is reported to be regulated by co-stimulatory molecules. T-cell immunoglobulin mucin-3 (Tim-3) and programmed death-1 (PD-1), two critical inhibitory co-stimulatory molecules, may affect the immune function of T lymphocytes via binding with their ligands, thus mediating the immune escape of tumor cells. Aims: To investigate the expressions and clinical significance of Tim-3 and PD-1 on γδ T cells in peripheral blood of colon cancer patients. Methods: Peripheral blood samples of 44 colon cancer patients were collected preoperatively at the First Affiliated Hospital of Soochow University from Dec. 2017 to Jun. 2018. Forty healthy volunteers were served as controls. The peripheral blood mononuclear cells (PBMCs) were isolated by density gradient centrifugation. Expressions of Tim-3 and PD-1 on γδ T cells were detected by flow cytometry, and their correlations with tumor clinicopathological characteristics were analyzed. Results: The proportions of Tim-3+, PD-1+ and Tim-3+PD-1+ γδ T cells in peripheral blood of colon cancer patients were significantly higher than those of healthy volunteers (P0.05). Conclusions: Tim-3 and PD-1 are highly expressed on γδ T cells in peripheral blood of colon cancer patients and associated with the clinicopathological stage of tumor. Expressions of Tim-3 and PD-1 on peripheral blood γδ T cells might be the promising objective indicators for evaluating the development and progression of colon cancer.