摘要目的：许多基因治疗方案可以诱导产生抗肿瘤免疫反应，但是ex vivo的操作方式限制了其应用。本研究采用瘤体内直接注射MHC Ⅱ类基因的方法来诱导抗肿瘤免疫反应。方法：针对具有弱免疫原性的小鼠肥大细胞瘤P815和非免疫原性的小鼠黑色素瘤B16，在瘤体的原位注射MHC Ⅱ类基因，观察肿瘤的生长情况。结果：直接注射MHC Ⅱ类基因，使P815肿瘤的致瘤性明显下降，并且对第二次接种P815细胞具有抵抗能力；虽然对B16而言，仅注射MHC Ⅱ类基因无治疗效果，但与B7基因共同注射，却能够显著地抑制B16肿瘤的生长。结论：瘤体内直接注射MHC Ⅱ类基因可以用来进行肿瘤治疗。

AbstractObjective: Many gene therapy protocols can induce antitumor immunity, however, the ex vivo approach restricts their uses. This sutydy intended to induce antitumor immunity by direct transfer of MHC class Ⅱ gene in vivo. Methods: MHC class Ⅱ gene cDNA was introduced directly into two tumors: P815, (a murine weak immunogenic mastocytoma) and B16 (a murine nonimmunogenic melanoma) to observe the survival rate of the mice. Results: Tumorigenicity of P815 was reduced when MHC class Ⅱ gene was introduced directly into tumors in vivo. Further more, most vaccinated mice could survive after second challenge of P815. Co-injection of MHC class Ⅱ and B7 genes in the B16 also resulted in the tumor grow slowly, while the injection of MHC class Ⅱ gene was not enough to induce effective antitumor responses. Conclusion: The results showed the potential applications of direct transfer of MHC class Ⅱ gene in the treatment of tumor.