应用移植瘤胃癌模型探讨Tregs对DC-CIK细胞抗肿瘤活性的影响

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

目的利用胃癌移植瘤模型探讨CD4+CD25+调节性T细胞(Tregs)对外周血来源的树突状细胞与细胞因子诱导的杀伤细胞(DC-CIK)体内抗肿瘤作用的影响。方法以SGC-7901胃癌细胞接种BALB/c裸鼠构建胃癌移植瘤模型。分离健康人外周血单个核细胞,体外诱导分化为DC-CIK细胞,培养分两组:DC-CIK组为常规单个核细胞诱导分化的DC-CIK;DC-CIK-Treg/del组为培养前利用免疫磁珠分选去除CD4+CD25+T细胞的外周血单个核细胞诱导分化的DC-CIK。流式细胞仪检测DC-CIK细胞表型,利用胃癌移植瘤模型观察两组DC-CIK细胞体内抑瘤作用。结果 DC-CIK细胞在培养第15天左右获得大量增殖,DC-CIK-Treg/del组细胞扩增倍数高于DC-CIK组,并且CD3+CD56+双阳性细胞所占的比例高于DC-CIK组(P<0.05);尾静脉注射DC-CIK细胞能抑制裸鼠体表移植瘤的生长,而去除Tregs的DC-CIK-Treg/del组对肿瘤的抑制作用明显高于DC-CIK组(P<0.05)。结论 DC-CIK细胞是一种具有较强体内抗肿瘤作用的免疫活性细胞。CD4+CD25+T细胞对DC-CIK细胞具有免疫抑制功能,去除CD4+CD25+T细胞,可增强机体的抗肿瘤作用,为有效治疗肿瘤提供了一种切实可行的方法。

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 ceils 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 （ P 〈 0. 05 ） ; DC - CIK cells had a stronger suppressive effect on tumor growth in nude mice beating 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 （P 〈 0.05 ） . Conclusion： DC - CIK cells are immunocompetent cells which have a stronger suppression against growth of tumor in vivo. CIM ＋ 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~ anti - tumor effect, which provide a practical method for the effective immunotherapy of tumor.