瘤体内直接注射白细胞介素-7基因抗小鼠乳腺肿瘤免疫效应的研究

Antitumor immune effect of interleukin-7 gene for mouse mammary cancer treated with direct intratumoral injection

目的观察瘤体内直接注射白细胞介素（IL）-7基因抗小鼠乳腺肿瘤免疫效应。方法构建IL-7真核表达质粒（pcDNA3-IL-7）；建立乳腺癌TM40D细胞BALB／C小鼠移植模型；瘤体内直接注射pcDNA3-IL-7，观察小鼠肿瘤体积变化；酶联免疫吸附试验（ELISA）法检测外周血干扰素（IFN）-γ含量；流式细胞仪检测胞内IFN-γ的分泌量；局部肿瘤经治疗后行常规病理分析。结果成功构建pcDNA3-IL-γ；与对照磷酸盐缓冲液（PBS）组（115．2±11．8）ng／L、pcDNA3组（133．6±9．4）ng／L比较，pcDNA3-IL-7注射组（242．3±10．1）ng／L外周血IFN-γ明显增高；pcDNA3-IL-γ明显抑制肿瘤生长（P〈0．05）；流式细胞仪检测显示pcDNA3-IL-7显著促进CD4＋T细胞、CD8＋T细胞内IFN-γ的分泌量；常规病理显示pcDNA3-IL-7注射组肿瘤组织大量坏死，炎性细胞和大量淋巴细胞浸润。结论瘤体内直接注射pcDNA3-IL-7明显抑制小鼠乳腺肿瘤生长，显著促进IFN-γ分泌，增强了小鼠机体抗乳腺肿瘤的免疫效应。

Objective To observe the antitumor immune effect of interleukin （IL）-7 gene for mouse mammary cancer treated with direct intratumoral injection. Methods IL-7 was constructed into the eukaryotic expression plasmid （pcDNA3-IL-7） ; breast cancer cell TM40D BALB/C mice transplantation model was established ; direct intratumoral injection of IL-7 eukaryotic expression plasmid DNA was done ; changes of tumor volume in mice were monitored; Enzyme linked immunosorbent assay （ELISA） assays were used to examine peripheral blood interferon （IFN）-7 production in tumor-bearing mice; the expression levels of intracellular IFN-7 in tumor-bearing mice spleen ceils were detected by using flow cytometry ; local tumor after treatment underwent routine pathological analysis. Results IL-7 was successfully constructed into the eukaryotic expression plasmid （pcDNA3-IL-7） ; the tumor growth rate in pcDNA3-IL-7 injection group was significantly reduced as compared with control group （ P 〈 0. 05 ） ; the production of peripheral blood IFN-γ in pcDNA3-IL-7 injection group （ 242. 3±10. 1 ） ng/L was significantly higher than in PBS group （ 115.2± 11.8） ng/L and pcDNA3 group （ 133.6±9.4） ng/L; the secretion of intracellular IFN-7 in CIM ＋ T cells and CD8 ＋ T cells was increased significantly ; routine pathologic examination showed that there were significant histological changes （ a large number of visible tumor necrosis, plentiful inflammatory cells and large lymphocytes infiltration） in the mice with direct intratumoral injection of IL-7. Conelusion Direct intratumoral injection of IL-7 gene eukaryotic expression plasmid significantly can inhibit the growth of mammary tumors in mice, significantly promote IFN-7 secretion in mice, and enhance the body＇ s immune response to mouse mammary tumor.