Cheung Ying-Kit, Cheng Samuel Chak-Sum, Sin Fion Wan-Yee, Chan Kin-Tak, Xie Yong
Department of Biology, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong SAR, China.
Vaccine. 2007 Aug 10;25(32):6070-7. doi: 10.1016/j.vaccine.2007.05.025. Epub 2007 Jun 4.
The severe acute respiratory syndrome coronavirus nucleocapsid protein (SARS-CoV N) is one of the major targets for SARS vaccine due to its high potency in triggering immune responses. In this study, we have identified a novel HLA-A*0201 restricted epitope, N220 (LALLLLDRL), of the SARS-CoV N-protein through bioinformatics analysis. The N-protein peptide N220 shows a high binding affinity towards human MHC class I in T2-cells, and is capable of activating cytotoxic T-cells in human peripheral blood mononuclear cells (PBMCs). The application of using the N220 peptide sequence with a single-chain-trimer (SCT) approach to produce a potential DNA vaccine candidate was investigated in HLA-A2.1K(b) transgenic mice. Cytotoxicity assay clearly showed that the T-cells obtained from the vaccinated animals were able to kill the N-protein expressing cells with a cytotoxicity level of 86% in an effector cells/target cells ratio of 81:1 one week after the last vaccination, which is significantly higher than other N-protein peptides previously described. The novel immunogenic N-protein peptide revealed in the present study provides valuable information for therapeutic SARS vaccine design.
严重急性呼吸综合征冠状病毒核衣壳蛋白（SARS-CoV N）因其在引发免疫反应方面的高效力，成为SARS疫苗的主要靶点之一。在本研究中，我们通过生物信息学分析，鉴定出一种新型的、受HLA-A*0201限制的SARS-CoV N蛋白表位N220（LALLLLDRL）。N蛋白肽N220在T2细胞中对人类MHC I类分子表现出高结合亲和力，并且能够激活人外周血单个核细胞（PBMC）中的细胞毒性T细胞。我们在HLA-A2.1K(b)转基因小鼠中研究了采用单链三聚体（SCT）方法利用N220肽序列制备潜在DNA疫苗候选物的应用。细胞毒性测定清楚地表明，在最后一次接种疫苗一周后，从接种动物获得的T细胞能够以81:1的效应细胞/靶细胞比例杀死表达N蛋白的细胞，细胞毒性水平达86%，这显著高于先前描述的其他N蛋白肽。本研究中揭示的新型免疫原性N蛋白肽为治疗性SARS疫苗设计提供了有价值的信息。
