Abstract
1 Laboratory of Hepatitis Viruses II, Department of Enteroviruses
2 Department of Veterinary Medicine
and3 Department of Medical Entomology, National Institute of Health, 2-10-35 Kamiosaki, Shinagawa-ku, Tokyo 141,
4 Department of Biological Science and Technology, Science University of Tokyo, Noda-shi 278,
5 St Marianna University School of Medicine, Kawasaki-shi 216
and6 Laboratory of Molecular Genetics, The Institute of Medical Sciences, The University of Tokyo, Minato-ku, Tokyo 108, Japan
A cDNA fragment encompassing the 5'-terminal half of the NS1 region of the hepatitis C virus (HCV) genome was cloned. The cDNA was expressed in insect cells using a recombinant baculovirus, and a protein band of approximately 21K was identified by immunoblotting with a serum sample from a patient with chronic hepatitis C. Antibody to the protein was detected in sera from 13.4% of patients with chronic non-A, non-B hepatitis (NANBH), 20.8% of patients with liver cirrhosis and 16.8% of patients with hepatocellular carcinoma with no serum markers for hepatitis B virus infection. However, the antibody was not detected in sera from patients with actute NANBH. The prevalence of antibody to the protein encoded by the NS1 region was lower than that of antibody to the HCV core protein, but much higher than that of antibody to the envelope protein. Thus, the NS1 region of the HCV genome is suggested to encode a protein produced during the course of HCV replication.