中文摘要：

目的：评价修饰的CEA610D抗原肽疫苗体外抗肿瘤免疫的有效性,为其临床应用提供依据。方法：多肽固相合成法合成HLA-A2CEA修饰肽（CEA610D）、HLA-A2天然肽CEA605-613（天然肽）和HLA-A2无关肽MAGE-3（无关肽）,采用同种异体混合淋巴细胞与肽共孵育的方法,诱导肽特异性细胞毒性T淋巴细胞（CTL）,利用MTT法检测CTL的增殖和杀伤活性 流式细胞术观察细胞表型 RT-PCR检测细胞穿孔素的表达 ELISA法检测CTL上清中IFN-γ的水平。结果：CEA610D疫苗产生肽特异性CTL的能力最强（P〈0.05）,其CD8＋T细胞数也高于天然肽组和无关肽组 在效靶比为40：1时,CEA610D和天然肽所诱导的CTL对CEA＋HLA-A2限制性人结肠癌细胞T84的杀伤活性可达（56.7±3.73）%和（51.2±1.86）%,而3种肽特异性CTL细胞对CEA＋HLA-A2人结肠癌lovo细胞杀伤活性维持在本底水平 CEA610D组的CTL所释放的杀伤相关介质穿孔素和上清中IFN-γ的水平也显著高于其余两组（P〈0.01）。结论：与天然肽相比,CEA610D疫苗可打破自身表位的免疫耐受,在体外抗肿瘤免疫中更具优势。

英文摘要：

Objective ：To investigated the in vivo efficacy of altered CEA610D peptide vaccine against tumor, so as to provide a basis for its clinical use. Methods： Altered CEA peptide CEA610D, natural CEA peptide CEA605-613 and MAGE- 3 peptide were synthesized by polypeptide solid-phase synthesis system. The cytotoxicity T lymphocytes （CTLs） were induced by autologous mixed lymphocytes reaction implused with above peptides; proliferation and cytotoxicity of different CTLs were measured by MTT; phenotypes of the CTLs were detected by flow cytometry ; expression of perforin in different CTLs were assayed by RT-PCR; IFN-γ levels in the supematants of different CTLs were detected by ELISA. Results： CEA610D peptide more efficiently induced CTL than CEA605-613 and MAGE-3 peptide did （P 〈 0.05）. The number of CD8＋ T cells in CEA610D group was significantly larger than those in CEA605-613 and MAGE-3 groups （P 〈 0. 05）. When the E： T was 40： 1, the cytotoxicity of CTLs induced by CEA610D and CEA605-613against CEA ＋ HLA-A2 ＋ T84 cells were （56.7 ± 3.73） % and （51.2 ± 1.86）%, respectively. But the CTL cytotoxicities induced by the three peptides against CEA ＋ HLA-A2-Lovo cells were all at the background level. Perforin expression and IFN-γ level of CTLs in CEA61oD group were significantly higher than those in the other two groups （P 〈 0.01 ）. Conclusion： Compared with natural CEA605-613 peptide, altered CEA60D peptide can effectively break the immune tolerance to self peptide, and thus has a stronger anti-tumor activity in vitro.