Association of hepatitis C virus particles with immunoglobulin: a mechanism for persistent infection

Biotech Research Institute, LG Chemical Ltd/Research Park 104-1 Munjidong, Yuseung-gu, Daejeon 305-380, Korea The physical properties of hepatitis C virus (HCV) particles were determined by ultracentrifugation on 20–60% isopycnic sucrose density gradients. We report that (i) two populations of HCV particles were found in the sera of patients with chronic HCV infection [at high density (1.186–1.213 g/ml) and at low density (1.099–1.127 g/ml)], (ii) virus particles with high density values were associated with immunoglobulin, and (iii) virus particles with low density values accumulated base changes within a hypervariable region (HVR) of the E2 envelope domain of the RNA genome. The results indicate that base changes within the HVR of E2 lead to the accumulation of immunoglobulin-free virus particles. Therefore, these findings imply that persistent HCV infection is established as a consequence of sequence variation in the E2 envelope domain. * Author for correspondence. Fax +82 42 862 0332. e-mail wsryu@twins.lgchem.co.kr Received 24 February 1995; accepted 4 May 1995.