Research Of Tumor Immune Response Mediates The Tumor-specific CD8~+T Cell And Regulatiry T Cell In Galectin-9Deficient Mice

Objective: In this study,we employed Galectin-9gene-targeted miceto investigate the role and mechanism of galectin-9deficiency on primarytumor growth and tumor metastasis and the frequency or phenotype andfunction of CD8+T cell and Tregs.Methods: The implanted tumor models were respectively establishedby injection of B16F10melanoma cells and EG7lymphoma cells in G9knockout mice(G9KO) and C57BL/6mice(WT),subcutaneously in righthind limb, monitored tumor size in every two days and drawn tumor growthcurve three weeks later. Established B16F10tumor lung metastasis modelwere injected intravenously and closely observation of lung cancermetastasis.Two weeks later,lung nodules were counted. Observed thedifference between the two groups.Take B16F10melanoma G9KO-/-C57BL/6right hind mice subcutaneous solid tumor model, tumors werecompletely isolated,tumor extracted by enzymatic digestion oftumor-infiltrating lymphocytes, and prepared into a single cell suspension, flow cytometry TIL in frequency and CD8+T lymphocytes phenotype withPMA stimulated CD8+T cells in4-6h, to detect the amount of INF-γsecreting cells, CD8+T lymphocyte function analysis. TIL also detected inCD4+Foxp3+Treg cells in the frequency analysis of the frequency of CD8+Tcells and Treg cell frequency ratio.Results: In the solid tumor-bearing mice model, compared with WTmice, G9KO mice were significantly resistant to B16F10(P <0.05) andEG7(P <0.05) in vivo tumor growth and prolong survival time; G9KO micewere significantly inhibited B16F10melanoma metastasis to the lung (P<0.001). By Flow cytometry shown that G9KO mice and WT mice, therewas no difference in the number of CD8+T-lymphocytes, but G9KO micewere increased local tumor CD8+T lymphocyte frequency (P <0.001), whileG9KO mice were significantly reduced functional CD8+T lymphocytephenotype (Tim-3+, PD-1+Tim-3+) frequency (P <0.05, P <0.001), G9KOmice were promoted the CD8+T cells secretion of INF-γ (P<0.01). Gatheredin the main local tumor CD4+Foxp3+Treg cells, G9KO mice weresignificantly reduced local tumor CD4+Foxp3+Treg cell frequency (P <0.01);G9KO mice were increased local tumor CD8+T cells reduced the number ofTreg cells, making CD8/Tregs ratio increased (P <0.001).Conclusion: The lack of galectin-9should delay tumor growth in vivo,inhibit tumor metastasis, reduce the exhaustion of tumor-specific CD8+T cell,then reduced immune function of local tumor Treg cells inhibition,enhance the body’anti-tumor immunity.