Antigenicity analysis of different regions of the severe acute respiratory syndrome coronavirus nucleocapsid protein

作者：Chen ZL; Pei DC; Jiang LX; Song YJ; Wang J; Wang HX; Zhou DS; Zhai JH; Du ZM; Li B; Qiu MF; Han YP; Guo ZB; Yang RF^*

来源：Clinical Chemistry, 2004, 50(6): 988-995.

DOI：10.1373/clinchem.2004.031096

Background: The widespread threat of severe acute respiratory syndrome (SARS) to human health has made urgent the development of fast and accurate analytical methods for its early diagnosis and a safe and efficient antiviral vaccine for preventive use. For this purpose, we investigated the antigenicity of different regions of the SARS coronavirus (SARS-CoV) nucleocapsid (N) protein.
Methods: The cDNA for full-length N protein and its various regions from the SARS-CoV was cloned and expressed in Escherichia coli. After purification, all of the protein fragments were printed on glass slides to fabricate a protein microarray and then probed with the sera from SARS patients to determine the reactivity of these protein fragments.
Results: The full-length protein and two other fragments reacted with all 52 sera tested. Four important regions with possible epitopes were identified and named as EP1 (amino acids 51-71), EP2 (134-208), EP3 (249-273), and EP4 (349-422), respectively. EP2 and EP4 possessed linear epitopes, whereas EP1 and EP2 were able to form conformational epitopes that could react with most (>80%) of the tested sera. EP3 and EP4 also formed conformational epitopes, and antibodies against these epitopes existed in all 52 of the sera tested.
Conclusion: The N protein is a highly immunogenic protein of the SARS-CoV. Conformational epitopes are important for this protein, and antigenicity of the COOH terminus is higher than that of the NH2 terminus. The N protein is a potential diagnostic antigen and vaccine candidate for SARS-CoV.

• 出版日期2004
• 单位中国人民解放军军事医学科学院