目的：探讨高度恶性的小鼠Ｔ淋巴细胞白血病细胞系Ｌ６１５转导Ｂ７１基因后激发移植宿主体内的抗肿瘤免疫情况。方法：以逆转录病毒为载体，将Ｂ７１基因导入小鼠白血病细胞系Ｌ６１５中，获得高表达Ｂ７１分子的Ｌ６１５Ｂ７细胞，作为肿瘤疫苗进行体内移植，观察其免疫保护作用并检测瘤苗体外激活的Ｔ细胞杀伤活性、细胞增殖和因子分泌情况。结果：体内移植实验表明Ｂ７１分子的表达可降低Ｌ６１５细胞在小鼠中的致瘤性，明显延长其生存时间。用Ｂ７瘤苗预先免疫小鼠，对随后的瘤细胞攻击有明显的免疫保护作用。Ｂ７瘤苗体外活化的Ｔ细胞对同种细胞有特异性杀伤活性，并可刺激Ｌ６１５Ｂ７的增殖。结论：Ｂ７１基因的导入并有效表达可增强肿瘤细胞免疫原性，激活Ｔ细胞，提高宿主抗瘤免疫 OBJECTIVE: To investigate the anti-tumor immunity of the highly transplanted mouse T lymphocyte leukemia cell line L615, which transduces the B71 gene and stimulates the transplanted host. METHODS: The retroviral vector was used to introduce the B71 gene into the mouse leukemia cell line L615. L615B7 cells with high expression of B71 molecule were obtained and used as a tumor vaccine for transplantation in vivo. The immunoprotective effect was observed and tested. T-cell killing activity, cell proliferation, and factor secretion of tumor vaccines in vitro. Results: Transplantation experiments in vivo showed that the expression of B71 molecule could reduce the tumorigenicity of L615 cells in mice and prolong its survival time. Preimmunization of mice with B7 tumor vaccines had significant immunoprotective effects on subsequent tumor cell challenge. B7 tumor vaccine in vitro activated T cells have specific killing activity against the same kind of cells, and can stimulate the proliferation of L615-B7. Conclusion: The introduction and effective expression of B71 gene can enhance the immunogenicity of tumor cells, activate T cells, and increase host antitumor immunity.