Characterization of Glycoproteins and Preparation of HCV Pseudoparticles with High Infectivity of Subtype 3b from Chinese Patients.

We wished to characterize the envelope protein coding gene of the hepatitis-C virus (HCV) from Chinese patients and prepare HCV pseudoparticles (HCVpp) of subtype 3b. Two of the HCV genotype 3b envelope protein coding genes (C27, C30) were cloned from Chinese HCV patients followed by sequencing analyses. Then, two envelope protein expression plasmids were constructed and characterized by western blotting. HCVpp were prepared and target cells infected in vitro. Results showed that the sequences of nucleotides and amino acids from two HCV subtype 3b envelope protein encoding genes (C27, C30) had high homology (98. 5% and 98. 2%, respectively) and had a close phylogenetic relationship with the international reference strain 3b TrKj. Ten amino-acid sites were substituted in the envelope protein coding region of C27 and C30. Expression of the C27 envelope protein was significantly higher than that of HCV subtype 1 (Conl) and C30. The corresponding HCVpp infectivity in vitro was also significantly different, whereby C27 could be used to prepare HCVpp subtype 3b with high infectivity. In conclusion, two envelope protein encoding genes of HCV subtype 3b were sequenced and their expression in vitro investigated. This is the first report on preparation of HCVpp subtype 3b with high infectivity. This study might provide an effective tool for HCV research and development of a vaccine for HCV.