HPV16 E7抗原CTL表位拟肽设计及活性评价

人乳头瘤病毒(human papillomavirus,HPV)早期基因E7是致癌的关键基因,其表达在宫颈癌细胞癌变进程及维持癌细胞恶性表型方面发挥重要作用,已成为宫颈癌治疗的理想靶标.目前,基于HPV16 E7抗原细胞毒性T淋巴细胞(cytotoxic lymphocyte,CTL)表位设计多肽疫苗是抗宫颈癌治疗发展的重要方向,但天然CTL表位肽普遍存在体内半衰期短、激发CTL反应效果不佳等缺点.因此,本研究基于前期HPV16 E7抗原CTL表位鉴定的基础,结合多肽酶解实验结果,进行分子动力学模拟及结合自由能计算,初步筛选了3条表位模拟肽.人工合成相关待测表位肽,并利用T2细胞株测定各肽与HLA-A2分子的结合力.研究结果表明,3条表位模拟肽体外抗酶解能力较天然HPV16 E7抗原CTL表位肽均有提高,以(d)RAHYNIVTF表位模拟肽的效果最为明显.此外,(d)RAHYNIVTF表位模拟肽与HLA-A2分子的结合力也有所提高(荧光系数为2.06).以上结果表明,基于HPV16 E7抗原CTL表位模拟肽进行结构修饰有望为宫颈癌治疗性疫苗的设计奠定基础.

HPV16 E7 CTL Epitope Antigen Peptide Design and Activity Evaluation

Human papillomavirus E7 gene is the key to cancer, which expressed in most HPV-contains cervical cancers. E7 plays an important role in the induction and maintenance of cellular transformation, and it was regarded as the ideal target in cervical cancer treatment. An important development direction of cervical cancer therapy is based on HPV16 E7 antigen CTL epitope peptide vaccine design, but Short half-life in vivo and poor stimulation effect are the major therapeutic obstacles for native CTL epitope peptide. In this study, three epitope peptides were screened by molecular dynamics simulations with MM-PBSA method, associated with previous research results and polypeptide enzymolysis experiment. These predicted peptides were synthesized, examining the affinity between HLA-A2 molecule and each peptide by T2 cell line. The result showed synthesized peptides had a great improvement on enzyme-resistant ability comparing with natural HPV16 E7 CTL epitope antigen peptide, and (d)RAHYNIVTF was the most obvious epitope peptide. Meanwhile, the affinity was improved between (d)RAHYNIVTF and HLA-A2 (fluorescence indexes was 2.06). The method of structural modification in this study is expected to lay the foundation for cervical cancer therapeutic vaccine design.