嵌合NY-ESO-1 DNA疫苗诱导黑色素瘤小鼠模型抗肿瘤免疫的研究

A Genetic Vaccine Encoding Chimeric NY-ESO-1 Induces Anticancer Immunity in A Mouse Model

NY-ESO-1作为一种肿瘤抗原,具有较强的免疫抗原性,并且已成为肿瘤候选疫苗之一。但由于目前大多应用NY-ESO-1多肽以及蛋白质疫苗,其临床试验效果欠佳,亟需更为有效的NY-ESO-1抗原设计的肿瘤免疫治疗出现。该研究的目的是探索将NY-ESO-1与具有增强免疫效应的五种因子分别重组成嵌合蛋白抗原,使其更有效地被加工、转运和呈递,以期找到最佳的基因佐剂,增强NY-ESO-1作为肿瘤治疗性DNA疫苗的免疫效果。采用电脉冲体内细胞高效转入的方法对C57BL/6小鼠进行DNA免疫,发现用编码NY-ESO-1或连接有HSP70的嵌合体质粒免疫可诱导强烈的NY-ESO-1特异性Ig G1反应。NY-ESO-1连接泛素的质粒免疫小鼠主要诱导NY-ESO-1特异性Ig G2a反应,表明此基因佐剂诱导强的Th1免疫反应。与其他嵌合NY-ESO-1质粒免疫相比,NYESO-1连接泛素的质粒免疫小鼠,有效地保护小鼠对有NY-ESO-1表达的B16F10黑色素瘤细胞系的挑战作用,证明强的Th1免疫反应对预防和治疗肿瘤具有重要作用。去除调节性T细胞(regulatory T cells,Treg)可进一步增强泛素-NY-ESO-1嵌合DNA疫苗治疗黑色素瘤的作用。此外,Ub-NY-ESO-1质粒结合编码异源黑素瘤抗原GP100和TRP-2的质粒免疫可诱导对抗含有NY-ESO-1表达的B16F10黑色素瘤的协同抗肿瘤免疫疗效。该研究结果表明,编码泛素-NY-ESO-1嵌合抗原的质粒DNA疫苗或与编码其他相关黑色素瘤抗原的质粒的联合可能是有效的治疗黑色素瘤的疫苗。

The NY-ESO-1 is one of the most immunogenic tumor antigens and an attractive candidate for developing cancer immunotherapy. However, trials using NY-ESO-1 peptide and protein vaccines so far have generated insufficient clinical outcomes, and improvement in antigen design is therefore needed for efficient cancer immunotherapy. In this study we designed different genetic vaccines （plasmids） encoding NY-ESO-1 fusion with various proteins that affect antigen processing, trafficking or presentation with the aim to identify an improvedgenetic adjuvant for this antigen. We studied the vaccines in a mouse model and measured humoral and cellular immune responses. We found that plasmids encoding NY-ESO-1 alone or linked with HSP70 induced strong NY- ESO-1-specific IgG1 response. Mice immunized with plasmid encoding ubiquitin-linked NY-ESO-1, however, induced primarily a NY-ESO-l-specific IgG2a response indicating that this genetic adjuvant drives the immune system towards a strong Thl response. Mice immunized with plasmid encoding ubiquitin-linked NY-ESO-1 showed significant enhanced protection against challenge with a B 16F 10 melanoma cell line expressing NY-ESO-1 as compared to other chimeric NY-ESO-1 vaccine constructs. It demonstrated the importance of a strong Thl response in tumor protection. Depletion of regulatory T （Treg） cells by denileukin diftitox further enhanced the antitumor effect of the ubiquitin-linked NY-ESO-1 DNA vaccine in a therapeutic study. Finally, combining ubiquitin-linked NY- ESO-1 construct with plasmids encoding the melanoma antigens gpl00 and TRP-2 induced a synergic antitumor effect against NY-ESO- 1 expressing B 16F I 0 tumor. Overall, these data suggested that genetic vaccine encoding the ubiquitin-linked NY-ESO-1, alone or in combination with other relevant melanoma antigens might be a potent therapeutic cancer vaccine.