树鼩间质视黄醇结合蛋白-3 T细胞抗原表位的预测及其致葡萄膜炎的活性

Prediction of retinol-binding protein 3(RBP3) epitopes in Chinese tree shrew and validation of its uveitogenic activity

目的:预测树鼩间质视黄醇结合蛋白-3(retinol-binding protein 3,RBP3)的T细胞抗原表位,评价其致葡萄膜炎的活性及免疫原性。方法:通过DNAMAN软件比对树鼩RBP3蛋白与人光感受器间维生素A类结合蛋白(interphotoreceptor retinolbinding protein,IRBP)、狒狒IRBP、牛IRBP、大鼠IRBP和小鼠IRBP氨基酸序列的同源性,利用DNAStar软件预测分析树鼩RBP3蛋白T细胞抗原表位及其与鼠主要组织相容性复合体Ⅱ类分子(major histocompatibility complexⅡ,MHC-Ⅱ)相互作用的抗原位点,合成上述预测的RBP3182-192抗原多肽片段评价其致B10.RIII小鼠的葡萄膜炎活性和免疫原性。结果:根据DNAMAN比对分析,树鼩RBP3与人IRBP、狒狒IRBP、牛IRBP、大鼠IRBP和小鼠IRBP的氨基酸同源性分别为83.50%、82.81%、82.23%、82.94%、82.63%。T细胞抗原表位的预测结果显示,RBP3含有47个潜在辅助性T细胞抗原优势表位和34个鼠MHC-Ⅱ类分子结合的CD4+T细胞抗原表位。合成包含预测抗原位点的RBP3182-192抗原多肽能够诱导出B10.RⅢ小鼠的全葡萄膜炎疾病和刺激其T淋巴细胞增殖。结论:树鼩RBP3蛋白包含较多CD4+T细胞抗原表位,选择并合成所预测的RBP3182-192抗原多肽具有诱导T淋巴细胞增殖的免疫活性和致小鼠葡萄膜炎的活性,可为诱导实验性自身免疫性葡萄膜炎树鼩新型模型的抗原筛选及葡萄膜炎研究提供基本理论依据。

Objective：To predict the epitopes of tree shrew retinal-binding protein 3 （RBP3） and to validate its uveitogenic activity. Methods：BLAST was utilized to compare the amino acid sequence homology of RBP3 protein with the IRBP of human,Papio Anubis, bovine, rat and mouse by DNAMAN. The antigenic sites of T cell epitopes of RBP3 and their interaction with murine MHC class Ⅱ molecules were analyzed by DNAStar software. The B10.R Ⅲ mouse was immunized by the predicted RBP3182-192 antigen peptide and T cell proliferation assay was conducted to assess its immunogenicity and pathogenicity. Results：According to DNAMAN alignment analysis,the amino acid homology of.the RBP3 protein in tree shrew with the IRBP of human,Papio anubis,bovine,rat and mice was 83.50%, 82.81% , 82.23% , 82.94% and 82.63% , respectively. Our results showed that T cell epitope of the RBP3 protein con- tained 47 potential T cell epitopes and 34 antigen sites that in teracted with murine MHC- Ⅱ molecule. Conclusion： Critically, experimental autoimmune uveitis（EAU）in B10.RⅢ mouse and T cell proliferation have also been successfully induced with the predicted RBP3182-192 antigen peptide,suggesting that the predicted T cell epitopes have uveitogenie activities and immunogenicity.