负载小鼠端粒酶逆转录酶基因的树突状细胞体内诱导抗肝癌免疫应答

目的 探讨小鼠端粒酶逆转录酶(mTERT)基因修饰的树突状细胞(Ad-mTERT-DC)在体内诱导抗肝癌活性的情况.方法 选用Bal B/c小鼠肝癌种植模型,用携带mTERT基因的重组腺病毒载体(Ad-mTERT)转染小鼠体外培养的DC,对同系小鼠进行免疫.采用酶联免疫吸附法(ELISA)检测脾细胞体外抗原再刺激后白介素2(IL-2)和γ干扰素(IFN-γ)水平,酶联免疫斑点法(ELISPOT)检测分泌IFN-γ细胞的数量,51Cr释放法检测细胞毒T淋巴细胞杀伤活性.接种H22细胞后,观察肿瘤大小及荷瘤小鼠存活情况.并进一步观察,在H22移植瘤存在的情况下,Ad-mTERT-DC是否能够有效抑制肿瘤生长.结果 小鼠脾细胞体外接受抗原再刺激后,Ad-mTERT组IL-2和IFN-γ水平以及IFN-γ分泌细胞的数量分别为871.25 pg/ml、169.15 ng/ml和378/106个脾细胞,显著高于Ad-GFP组(131.6 pg/ml、15.4 ng/ml和36/106个脾细胞,均P<0.05)、DC组(71.3 pg/ml、10.5ng/ml和21/106个脾细胞)和PBS组(65.8 pg/ml、7.4 ng/ml和18/106个脾细胞,均P<0.05).Ad-mTERT-DC能诱导特异性CTL的产生,在效靶比为90:1时,Ad-mTERT组的特异性杀伤率为58.7%,明显高于Ad-GFP组(10.3%)、DC组(2.9%)和PBS组(1.7%).接种后第27天,Ad-mTERT组中成瘤小鼠的肿瘤平均直径明显低于各对照组(P<0.05),小鼠存活时间明显延长(P<0.05).Ad-mTERT组抑瘤率为43.6%,明显高于PBS组、DC组和Ad-GFP组(均P<0.01).结论 Ad-mTERT-DC在小鼠体内可诱导出mTERT抗原特异性的抗肿瘤活性,对肝癌有预防和治疗作用.

Immunization with dendritic cells infected with mTERT adenovirus vector effectively elicits immunity against mouse H22 hepatoma in vivo

Objective To investigate the effects of dendritic cells (DCs) infected with adenovirus vector encoding mTERT on induction of mTERT antigen specific immunity against H22 hepatoma in vivo. Methods Forty Bal B/c mice were subcutaneously immunized with Ad-mTERT infected DC. Cytotoxicity of mTERT specific CTL was determined by 51Cr release assay. IL-2 and IFN-γ were tested by ELISA. IFN-γ ELISPOT assays were performed for measuring antigen specific IFN-γ production by T cells. Tumor size and survival of the immunized mice were recorded and evaluated whether preexisting hepatoma metastases could be supressed after immunization with mTERT-expressing DCs. Results The lyric activity of CTL, IL-2 (871.25 pg/ml), IFN-γ(169.15 ng/ml) and IFN-γ secreting cells (378/106 spleen cells) elicited by the Ad-mTERT infected DCs were much stronger and higher than that by Ad-GFP group( 131.6 pg/ml, 15.4 ng/ml, 36/106 spleen cells, P < 0. 05 ), DC group ( 71.3 pg/ml, 10.5 ng/ml, 21/106 spleen cells, P < 0.05), PBS group(65.8 pg/ml, 7.4 ng/ml, 18/106 spleen cells,P<0.05). In prophylaxis and treatment experiment the Ad-mTERT/DCs immunized mice lived significantly longer than other groups, demonstrating that primary DCs were genetically modified to express the mTERT antigen and could suppress the tumor growth. Conclusion Adenovirus vector mediated mTERT infected DCs can effectively induce mTERT antigen specific antitumor activity, and can induce protective and therapeutic antitumor immunity.