SEQUENCE-ANALYSIS OF HYPERVARIABLE REGION OF HEPATITIS-C VIRUS (HCV) ASSOCIATED WITH IMMUNE-COMPLEX IN PATIENTS WITH CHRONIC HCV INFECTION

Immune complex (IC) frequently exists in sera of patients with hepatit is C virus (HCV) infection, When circulating HCV particles are fractio nated by differential flotation ultracentrifugation, HCV in the bottom fraction appears to be in the form of IC. Flotation ultracentrifugati on of serum was done in 7 patients positive for serum anti-C3d-binding circulating IC and in 7 negative patients. In all IC-positive patient s, HCV RNA was detected in the bottom fraction but not in the top frac tion of 3 patients, Amino acid sequences of hypervariable region (HVR) of HCV in the bottom fraction of IC-positive patients were almost the same as those of whole serum, while those of the top fraction conside rably differed from those of whole serum except for 1 case. These data suggest that the major population of HCV forms IC in IC-positive pati ents, and antibody response to the HVR of HCV is responsible for IC fo rmation.