OBJECTIVETo generate hepatitis C virus pseudo-particles (HCVpp) containing the complete E1-E2 envelope glycoprotein, in order to establish a HCVpp database covering the six major genotypes of HCV (1b, 2a, 3b, 4, 5, and 6) and to develop a simple and effective method for detection of neutralizing antibodies in HCV patients.

METHODSHCVpp were generated for the six genotypes by co-transfecting 293T cells with a plasmid expressing the respective E1-E2 (p HR, CMVA 8.2 construct) and a MLV-GFP plasmid. Titration of each HCVpp was carried out by p24 ELISA. Infectivity of each HCVpp was assessed by mixing the harvested supernatant of producer cells with sera from HCV patients, adding the mixture to Huh-7 cells, and detecting the subsequent titers of neutralizing antibodies against HCVpp.

RESULTSAll six types of HCVpp were able to infect Huh-7 cells in vitro. For healthy HCV carriers, only two genotypes of HCVpp (1b and 2a) produced neutralizing antibody titers more than 1:40. For cured HCV patients, only the 1b genotype produced neutralizing antibody titers more than 1:40. One patient showed titer of 1:200 for genotype 4. A healthy spouse of a chronic hepatitis C patient showed titers more than 1:40 for four genotypes of HCVpp (3a, 4, 5, 6).

CONCLUSIONWe generated six different genotypes of HCVpp successfully, established the in vitro neutralizing antibody detection method, and provided an effective model for screening antiviral drugs.