通过维持微环境IL－2水平抑制肿瘤形成

为研究肿瘤微环境中ＩＬ－２对肿瘤生长的抑制效应，用转基因方法，将携带ｍＩＬ－２ｃＤＮＡ基因的牛乳头瘤病毒载体（ＢＣＭＧ）转染小鼠Ｂ１６瘤细胞，获稳定持久分泌ｍＩＬ－２的Ｂ１６细胞株（ｍＩＬ－２＋Ｂ１６）。动物实验结果显示：ｍＩＬ－２＋Ｂ１６细胞的致瘤性明显下降，但体外生长率与其亲代Ｂ１６细胞相比较无区别。用ｍＩＬ－２＋Ｂ１６细胞诱导的小鼠腹腔渗出细胞（ＰＥＣ）对ＹＡＣ－１靶细胞和Ｂ１６靶细胞的体外杀伤能力比对照组ＰＥＣ（Ｂ１６诱导的ＰＥＣ）高一倍以上（Ｐ＜０．０１）。表明提高微环境中的ＩＬ－２水平能提高抗肿瘤免疫细胞对肿瘤细胞的杀伤能力，从而抑制肿瘤的形成。

Inhibition of Tumor Formation in vivo via Increased IL-2 Level in Microenvironment

To study the antitumor effect of local production of Interleukin-2(IL-2) from B16 tumor cells, the murine melanoma cells were transfected with murine IL-2 cDNA in a bovine papilloma virus vector(BCMG) by electrical pulse method. A B16 cell line of steadily secreting mIL-2(mIL-2+B16) was obtained. Experimental results showed that the mIL-2+B16 cell line did not alter their growth rate compared with its parental B16 cells in vitro, but their ability of tumorigenesis in vivo was reduced. Intraperitoneal inoculation of IL-2+B16 generated a large number of peritoneal exudate cells(PEC) and these cells had a higher cytotoxic activity against B16 and YAC-1 compared with those PEC induced by B16 inoculation. The results suggest that increased IL-2 level in microenvironment of tumor cells can enhance the cytolytic activity of immune cells and thus inhibit the tumor-formation.