白细胞介素-7促进CD8^＋T细胞干扰素-γ的分泌增强小鼠抗乳腺肿瘤的免疫效应

Enhancement of antltumor effect on breast cancer by interleukln-7-indueed interferon-γ production

目的观察白细胞介素（IL）-7是否通过促进CD8^＋T细胞干扰素-1（IFN-y）分泌来增强小鼠抗乳腺肿瘤的免疫效应。方法荷瘤小鼠瘤体内直接注射IL-7真核表达质粒（pcDNA3一IL-7）；免疫磁珠分选CD4^＋T、CD8^＋T细胞并体外培养；流式细胞仪检测细胞内干扰素（IFN）-7的分泌量；酶联免疫吸附试验（ELISA）检测培养上清IFN-1的量；噻唑蓝（MTr）法检测CD8^＋T细胞体外杀伤活性；小鼠体内预先注射anti—CD8抗体阻断活化。结果pcDNA3-IL-7注射组CD8^＋T细胞内IFN-1（38．6±4．4）％、CD8^＋T细胞培养上清IFN一1（136．0±11．2）ng／L，与对照组比较，pcDNA3一IL-7明显促进CD8^＋T细胞IFN．1表达量（P〈0．05）；IL-7处理过的荷瘤小鼠CD8^＋T细胞杀伤活性显著增强，尤其效靶比为100：I；小鼠体内预先注射anti-CD8抗体阻断CD8^＋T细胞活化，显著抑制IL-7抗瘤效应（P〈0．05）。结论IL-7通过促进小鼠体内CD8^＋T细胞分泌IFN-1介导抗瘤效应，从而增强小鼠机体抗乳腺肿瘤的免疫反应。

Objective To investigate whether inter｜enkin （IL）-7 enhances antitumor effect on breast cancer by promoting interferon （IFN）-T production in CD8^＋T cells in a mouse model. Methods The tumor-bearing mice were subjected to direct intratumoral injection of PODNA3-IL-7. Spleen CD4 ＋ and CD8^＋ T cells were enriched from tumor-bearing mice using magnetic heads and cultured in vitro. Enzyme linked immunosorbent assay （ELISA） was used for IFN-γ/detection in splenocyte culture supernatants. The intracellular expression of IFN--y in splenocytes was detected by using flow cytometry. MTI method was used to detect CD8^＋ T cell-mediated cytotoxicity. In vivo antitnmor effect of IL-7 was assessed by neutrali- zing CD8^＋T ceils with anti-CD8 monoclonal antibodies in tumor-bearing mice. Results The secretion of intracellular IFN-~/in CD8 ＋ T cells （38. 6 ＋ 4.4） % and the production of IFN-~/fromCD8^＋T ceils cul- ture supernatants （136. 0 ＋ 11.2） ng/L in pcDNA3-IL-7 injection group were significantly increased as compared with those in control group. IL-7 could promote IFN-~ production by CD8^＋T cells. IL-7 could profoundly enhance spleen CD8^＋ T cell-mediated cytotoxicity in tumor-bearing mice, and the cytotoxicity was more significant at the ratio orE （effect） to T （target） as 100：1. Antitumor effect of IL-7 was signifi- cantly inhibited after neutralizing CD8^＋ T cells by anti-CD8 monoclonal antibody injection into tumor-bear- ing mice. Conclusion Interleukin-7 enhances antitumor effect on breast cancer through promoting IFN-~ production by CD8 ＋ T cells. IL-7-mediated antitumor effect enhances immune response to mammary tumor