Influence of regulatory T cells on antitumor activity of dendritic cells-cytokine induced killer cells in gastric cancer xenograft models

Objective:To investigate the in vivo anti-tumor effect of CD4+CD25+ regulatory T cells on dendritic cells-cytokine induced killer cells(DC-CIK) from peripheral blood in gastric cancer xenograft model.Methods: The BALB/c nude mice inoculated with gastric cancer cell line SGC-7901 were used as animal model.Peripheral blood mononuclear cells were isolated from healthy human.The experiment were divided into two groups: DC-CIK cells group(conventional mononuclear cells were induced to DC-CIK cells) and DC-CIK-Treg/del cells group(the peripheral mononuclear cells depleting CD4+ CD25 + regulatory T cell by+ immunomagnetic beads sorting were induced to DC-CIK cells).The cells phenotype were detected with flow cytometry;the antitumor activity of the DC-CIK cells in vivo were evaluated in BALB/c nude mice.Results: The cell proliferation of DC-CIK-Treg/del group is higher than the DC-CIK group,The levels of CD3+CD56+ were significantly increased in DC-CIK-Treg/del group after 15 days in DC-CIK culture(P0.05);DC-CIK cells had a stronger suppressive effect on tumor growth in nude mice bearing subcutaneous in vivo.The infusion of DC-CIK cells inhibited the growth of tumor cells inoculated in the mice.The tumor inhibition was significantly higher in the DC-CIK-Treg/del group than the DC-CIK group(P0.05).Conclusion: DC-CIK cells are immunocompetent cells which have a stronger suppression against growth of tumor in vivo.CD4+ CD25 + regulatory T cell with immunosuppressive fuction in DC-CIK cells could reduce the antitumor effect and removal of CD4+ CD25 + regulatory T cell could enhance the body's anti-tumor effect,which provide a practical method for the effective immunotherapy of tumor.