Abstract:

Objective To study the changes of CD4⁺CD25⁺Treg cells and immunesurveillance function in tumor infiltrating lymphocytes(TIL) and investigate the relationship between CD4⁺CD25⁺Treg cells and tumor immune escape. Methods TIL and spleen cells of the S180 ascites carcinoma mice and spleen cells of the control ones were used for the following detection: the quantities of CD4⁺CD25⁺Treg cells,CD8⁺T cells,NK cells and NKG2D were detected by flow cytometry;the expression level of Foxp3 mRNA was detected by RT-PCR;the killing function of CD8⁺T cells was detected by lactate dehydrogenase release assay. Results Compared with control mice，the quantity of CD4⁺CD25⁺Treg cells and the expression of Foxp3 mRNA were significantly increased in the TIL and spleen cells of the tumor mice (P<0.05);furthermore,the quantity of CD4⁺CD25⁺Treg cells and the expression of Foxp3 mRNA in TIL were both higher than those in spleen cells of tumor mice;the number of CD8⁺T cells in TIL was significantly increased(P<0.05),while the killing function of CD8⁺T cells in TIL was decreased;the number of NK cells and the expression of NKG2D in TIL were significantly increased (P<0.05). Conclusion The quantity and function of CD4⁺CD25⁺Treg cells are significantly increased in location of tumor which might be one of the mechanisms of tumor escaping from immune surveillance.

Key words: CD4+CD25+Treg cells;Foxp3;tumor infiltrating lymphocytes;tumor immunity