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

Abstract

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 NH(2) terminus. The N protein is a potential diagnostic antigen and vaccine candidate for SARS-CoV.

• Authors: Zeliang Chen, Decui Pei, Lingxiao Jiang, Yajun Song, Jin Wang, Hongxia Wang, Dongsheng Zhou, Junhui Zhai, Zongmin Du, Bei Li, Maofeng Qiu, Yanping Han, Zhaobiao Guo, Ruifu Yang
• Journal: Clinical chemistry (Clin Chem) Vol. 50 Issue 6 Pg. 988-95 (Jun 2004) ISSN: 0009-9147 [Print] England
• PMID: 15054081 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Antigens, Viral
• Coronavirus Nucleocapsid Proteins
• DNA, Complementary
• Epitopes
• Nucleocapsid Proteins

Topics

• Antigens, Viral (genetics, immunology)
• Cloning, Molecular
• Coronavirus Nucleocapsid Proteins
• DNA, Complementary (genetics)
• Epitopes
• Escherichia coli (metabolism)
• Humans
• Nucleocapsid Proteins (biosynthesis, genetics, immunology)
• Protein Array Analysis
• Severe acute respiratory syndrome-related coronavirus (immunology, isolation & purification)
• Severe Acute Respiratory Syndrome (diagnosis)