Characterization of Norwalk virus GI specific monoclonal antibodies generated against Escherichia coli expressed capsid protein and the reactivity of two broadly reactive monoclonal antibodies generated against GII capsid towards GI recombinant fragments
1 Division of Food Microbiology, Osaka Prefectural Institute of Public Health, Nakamichi 1-3-69, Higashinari-ku, Osaka 537-0025, Japan
2 Division of Pathology, Osaka Prefectural Institute of Public Health, Nakamichi 1-3-69, Higashinari-ku, Osaka 537-0025, Japan
3 Division of Virology, Osaka Prefectural Institute of Public Health, Nakamichi 1-3-69, Higashinari-ku, Osaka 537-0025, Japan
4 Division of Industrial Health, Osaka Prefectural Institute of Public Health, Nakamichi 1-3-69, Higashinari-ku, Osaka 537-0025, Japan
5 Department of Pharmacology, Osaka University of Pharmaceutical Sciences, Nasahara 4-20-1, Takatsuki, Osaka 569-1094, Japan
6 Department of Molecular Microbiology, the Gifu Prefectural Institute for Bio-industrial Technology, 3481-2 kamihachiya Hachiya-cho, Minokamo, Gifu 505-0004, Japan
7 Department of Virology II, National Institute of Infectious Diseases, Shinjuku-ku, Tokyo 162-8640, Japan
8 Gifu Research Laboratory, Immunology Division, JBS Inc., Kaidu, Gifu 503-0617 Japan
BMC Microbiology 2001, 1:24 doi:10.1186/1471-2180-1-24Published: 8 October 2001
Norwalk virus causes outbreaks of acute non-bacterial gastroenteritis in humans. The virus capsid is composed of a single 60 kDa protein. In a previous study, the capsid protein of recombinant Norwalk virus genogroup II was expressed in an E. coli system and monoclonal antibodies were generated against it. The analysis of the reactivity of those monoclonal antibodies suggested that the N-terminal domain might contain more antigenic epitopes than the C-terminal domain. In the same study, two broadly reactive monoclonal antibodies were observed to react with genogroup I recombinant protein.
In the present study, we used the recombinant capsid protein of genogroup I and characterized the obtained 17 monoclonal antibodies by using 19 overlapping fragments. Sixteen monoclonal antibodies recognized sequential epitopes on three antigenic regions, and the only exceptional monoclonal antibody recognized a conformational epitope. As for the two broadly reactive monoclonal antibodies generated against genogroup II, we indicated that they recognized fragment 2 of genogroup I. Furthermore, genogroup I antigen from a patient's stool was detected by sandwich enzyme-linked immunosorbent assay using genogroup I specific monoclonal antibody and biotinated broadly reactive monoclonal antibody.
The reactivity analysis of above monoclonal antibodies suggests that the N-terminal domain may contain more antigenic epitopes than the C-terminal domain as suggested in our previous study. The detection of genogroup I antigen from a patient's stool by our system suggested that the monoclonal antibodies generated against E. coli expressed capsid protein can be used to detect genogroup I antigens in clinical material.