A laboratory-adapted HCV JFH-1 strain is sensitive to neutralization and can gradually escape under the selection pressure of neutralizing human plasma

• Published in: Virus research Vol. 169; no. 1; pp. 154 - 161
• Main Authors: Song, Hongshuo, Ren, Furong, Li, Jin, Shi, Shuang, Yan, Ling, Gao, Feng, Li, Kui, Zhuang, Hui
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.10.2012
• Subjects: Adaptations; Adult; Antibodies; Antibodies, Neutralizing - immunology; Blood; Cell culture adaptation; Cell Line, Tumor; Data processing; Envelopes; Epitopes; Escape mutation; HCV; Hepacivirus - genetics; Hepacivirus - growth & development; Hepacivirus - immunology; Hepatitis C; Hepatitis C Antibodies - immunology; Hepatitis C virus; Hepatocytes - virology; Hepatoma; Humans; Immune Evasion; Infection; Male; Molecular modelling; Mutation; Mutation, Missense; Neutralization; Replication; Viral Envelope Proteins - genetics; Viral Envelope Proteins - immunology; Virus Cultivation; Young Adult; HCV; Cell culture adaptation; Escape mutation; Neutralization
• ISSN: 0168-1702; 1872-7492
• DOI: 10.1016/j.virusres.2012.07.022

► We screened the neutralizing activity of 7 anti-HCV positive human plasma samples from individuals who have cleared the virus. ► A cell-culture adapted JFH-1 strain is more sensitive to neutralization than wild-type JFH-1. ► We applied nAb selection pressure onto the cell-culture adapted JFH-1. ► The E2 residues T414 and P500 are critical residues under the selection pressure of nAbs. Viral replication and neutralization of hepatitis C viruses (HCV) have been studied using the infectious molecular clone JFH-1. By passaging JFH-1 in hepatoma cells in the absence or presence of HCV neutralizing antibodies (nAbs), we investigated the molecular mechanisms of cell-culture adaptation and sensitivity to nAbs. The cell culture-adapted JFH-1 virus (JFH-1-CA) became more sensitive to nAbs than its parental virus. Sequence analysis revealed that the predominant viruses in the JFH-1-CA population carried two mutations in their envelopes (I414T and V293A). Plasma that could neutralize JFH-1-CA was found in 2 of 7 HCV-infected individuals who have cleared the virus in blood. Plasma 226233 with a higher 50% neutralization titer was used for in vitro selection of neutralization resistant viruses. Under the increasing selection pressure of plasma 226233, the neutralizing sensitivity of JFH-1-CA decreased gradually. Two mutations (T414I and P500S) in envelope were found in all but one sequenced clones in the viral population after eight rounds of selection. Interestingly, the cell-culture adapted mutation I414T reverted back to the wild-type residue (I414) under the selection pressure. By introducing mutations at positions 414 and 500 into the JFH-1 clone, we confirmed that the T414I mutation alone can confer neutralization resistance. The results of this current study suggest that nAbs are present in a subset of HCV-infected individuals who have cleared the virus in blood. Our data also provide the first evidence that, the E2 residue P500, located within a previously identified highly conserved polyclonal epitope, may be a target for neutralizing antibodies present in individual who have spontaneously resolved the HCV infection.