辅助性T细胞和细胞毒性T淋巴细胞双表位修饰的树突状细胞肿瘤疫苗治疗胃癌的实验研究

目的研究辅助性T细胞（Th）表位和细胞毒性T淋巴细胞（CTL）双表位修饰的树突状细胞（DCs）肿瘤疫苗用于胃癌免疫治疗的效果。方法用CTL表位MAGE-341-49和Th表位MAGE-322-36混合多肽冲击DCs，每周刺激脾脏T细胞1次，4周后收集多肽特异性T细胞。流式仪分析T细胞亚群分布，测定CD4^＋T细胞识别抗原细胞因子分泌及CD8^＋T细胞杀伤肿瘤细胞效能，观察双表位修饰的DCs肿瘤疫苗治疗胃癌的保护性免疫效应。结果双表位致敏的DCs体外可同时活化CD4^＋和CD8^＋T细胞，其中CD4^＋T细胞识别肿瘤细胞小鼠前胃癌细胞株MFC后分泌大量Th1型细胞因子[干扰素（IFN）-γ，白介素（IL）-2]，CD8^＋T细胞强效杀伤MFC。双表位修饰的DCs肿瘤疫苗小鼠体内免疫治疗获得抵抗后继胃癌细胞MFC的免疫保护能力，并显著高于单一表位（CTL或Th）修饰的DC8疫苗。结论Th和CTL双表位修饰的DCs肿瘤疫苗可同时激活CD4^＋Th1细胞和CD8^＋CTL抗肿瘤免疫，有效清除胃癌细胞。

Immunotherapeutic efficacy of both helper T lymphocytes and cytotoxic T lymphocytes epitopes augmented dendritic cells tumor vaccine on gastric cancer

OBJECTIVE: To investigate the immunotherapy efficacy of both helper T lymphocytes (Th) and cytotoxic T lymphocytes (CTL) epitopes augmented dendritic cells (DCs) tumor vaccine on gastric cancer. METHODS: Na?ve spleen T cells were stimulated by mixed peptides (a mixture of Th epitope MAGE-3 (22-36)) primed DCs per week in vitro. After 4 cycles of restimulation, peptide specific T cells were harvested and subgroups of which were determined with flowcytometry. Cytokines secreting profiles by CD4+ T cells and cytotoxicities of CD8+ T cells on tumor cells were assessed. The protective immunity by referred DCs tumor vaccines was also monitored. RESULTS: Both Th and CTL epitopes primed DCs could elicit both CD4+ T cells and CD8+ T cells in vitro,of which CD4+ T cells released high amount of Th1 type cytokines (IFN-gamma, IL-2) on recognizing specific antigen, as well as CD8+ T cells exhibited efficient tumor-killing capacity. The effects induced by DCs pulsed with single epitope (Th or CTL epitope) in vivo were less effective than those induced by DCs pulsed with mixture epitopes. CONCLUSIONS: Both Th and CTL epitopes augmented DCs tumor vaccine can induce CD4+ Th1 and CD8+ CTL mediated immune responses to eradicate gastric cancer cells.