人肿瘤转移相关抗原肝素酶HLA-A2.1限制性CTL表位的预测及初步鉴定

Prediction and peptide binding assay of HLA-A2.1-restricted CTL epitope from heparanase

目的预测并鉴定肿瘤转移相关抗原肝素酶来源的HLA-A2.1限制性CTL表位。方法采用超基序、量化基序和分子模拟相结合的方法,对肝素酶HLA-A2.1限制性CTL表位进行预测,合成候选表位肽;利用T2细胞的特点,对合成的候选肽与HLA-A2.1分子进行亲和力分析,初步验证预测结果;利用标准51Cr释放试验检测特异性CTLs诱导活性。结果在所筛选的5个候选CTL表位中,Hpa(525-533)、Hpa(277-285)、Hpa(405-413)可在体外有效诱导肝素酶特异性CTLs的产生,对肝素酶阳性且HLA-A2阳性的KATO-Ⅲ细胞具有明显的杀伤效应。结论Hpa(525-533)、Hpa(277-285)、Hpa(405-413)有可能是肿瘤抗原肝素酶HLA-A2.1的限制性CTL表位。

Objective To predict and identify the HLA-A2. 1-restricted cytotoxic T lymphocyte （CTL） epitopes in heparanase （Hpa）, a new tumor associated antigen. Methods Supermotif and quantitative motif methods were used to predict the CTL epitopes. Then the prediction was evaluated by T2 binding test. Results Five predicted highest score candidate epitopes were Hpa（525 -533）, Hpa（353 -361）, Hpa（277 - 285 ）, Hpa（400 -408 ） and Hpa（405 -413 ）. The results of molecular simulations showed that the 5 candidate peptides could effectively bind with HLA-A2.1. Further peptide binding assay demonstrated that these 5 candidate peptides bound to HLA-A2. 1 with high affinity. Hpa （525 - 533 ）, Hpa （277 - 285 ） and Hpa （405 - 413 ） induced heparanase-specific immune responses against KATO-Ⅲ gastric tumor cells, which was both positive for heparanase and HLA-A2. Conclusion Hpa（525 -533）, Hpa（277 -285） and Hpa（405 -413） might be the HLA-A2. 1- restricted epitope of Hpa.