Mutations That Alter Use of Hepatitis C Virus Cell Entry Factors Mediate Escape From Neutralizing Antibodies

Inserm, U748, Hôpitaux Universitaires de Strasbourg, Strasbourg, France.
Gastroenterology (Impact Factor: 16.72). 04/2012; 143(1):223-233.e9. DOI: 10.1053/j.gastro.2012.04.006
Source: PubMed


The development of vaccines and other strategies to prevent hepatitis C virus (HCV) infection is limited by rapid viral evasion. HCV entry is the first step of infection; this process involves several viral and host factors and is targeted by host-neutralizing responses. Although the roles of host factors in HCV entry have been well characterized, their involvement in evasion of immune responses is poorly understood. We used acute infection of liver graft as a model to investigate the molecular mechanisms of viral evasion.
We studied factors that contribute to evasion of host immune responses using patient-derived antibodies, HCV pseudoparticles, and cell culture-derived HCV that express viral envelopes from patients who have undergone liver transplantation. These viruses were used to infect hepatoma cell lines that express different levels of HCV entry factors.
By using reverse genetic analyses, we identified altered use of host-cell entry factors as a mechanism by which HCV evades host immune responses. Mutations that alter use of the CD81 receptor also allowed the virus to escape neutralizing antibodies. Kinetic studies showed that these mutations affect virus-antibody interactions during postbinding steps of the HCV entry process. Functional studies with a large panel of patient-derived antibodies showed that this mechanism mediates viral escape, leading to persistent infection in general.
We identified a mechanism by which HCV evades host immune responses, in which use of cell entry factors evolves with escape from neutralizing antibodies. These findings advance our understanding of the pathogenesis of HCV infection and might be used to develop antiviral strategies and vaccines.

Download full-text


Available from: Francois habersetzer, Dec 17, 2013
  • Source
    • "Mutations in the GPs confer viral escape to humoral responses by altering the use of the host cell receptors Fofana I. et al., Gastroenterology 2012 HCV genetic variability allows the virus its adaptation to the host "
    [Show abstract] [Hide abstract]
    ABSTRACT: Hepatitis C virus (HCV) infects an estimated more than 150 million people and is a leading cause of liver disease worldwide. The development of direct-acting antivirals (DAAs) will markedly improve the outcome of antiviral treatment with cure of the majority of treated patients. However, several hurdles remain before HCV infection can be considered a menace of the past: High treatment costs will most likely result in absent or limited access in middle and low resource countries and will lead to selective use even in wealthier countries. The limited efficacy of current HCV screening programs leads to a majority of cases being undiagnosed or diagnosed at a late stage and DAAs will not cure virus-induced end-stage liver disease such as hepatocellular carcinoma. Certain patient subgroups may not respond or not be eligible for DAA-based treatment strategies. Finally, reinfection remains possible, making control of HCV infection in people with ongoing infection risk difficult. The unmet medical needs justify continued efforts to develop an effective vaccine, protecting from chronic HCV infection as a mean to impact the epidemic on a global scale. Recent progress in the understanding of virus–host interactions provides new perspectives for vaccine development, but many critical questions remain unanswered. In this review, we focus on what is known about the immune correlates of HCV control, highlight key mechanisms of viral evasion that pose challenges for vaccine development and suggest areas of further investigation that could enable a rational approach to vaccine design. Within this context we also discuss insights from recent HCV vaccination studies and what they suggest about the best way to go forward.
    Preview · Article · Nov 2014 · Journal of Hepatology
  • Source
    • "Mutations that alter use of the CD81 receptor also allowed the virus to escape neutralizing antibodies. These experiments replicate the mechanism of viral infection, mediating viral escape and leading to persistent infection in general [Fofana et al., 2012]. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Several cell surface molecules have hepatitis C virus (HCV) binding properties and may serve as receptors facilitating viral entry into cells. The large extracellular loop (LEL) of CD81 has been shown to bind the HCV envelope protein E2 with several critical residues for the CD81-HCV-E2 interaction. It was hypothesised that variation in the CD81 LEL sequence may modify susceptibility to HCV infection. HCV RNA negative patients with spontaneous viral clearance (RNA -ve); HCV RNA positive cases, who are affected chronically (RNA +ve); and patients at high risk of HCV infection, exposed but uninfected patients (EU) were studied. Genomic DNA was extracted from whole blood samples and four exons of the CD81 LEL gene were amplified by PCR and sequenced. The cDNA derived from CD81 (≈700 bp) was sequenced following RNA extraction from peripheral blood mononuclear cells. Patients, who are RNA positive, RNA negative, and exposed uninfected were sequenced for four DNA sections (A, B, C, and D). Sixty-two (43M:19F) patients, from all the patient cohorts, were sequenced and compared for the C section alone (which encompasses the important binding region of the molecule for envelope protein) including 21 (14M:7F) HCV RNA negative, 15 (10M:5F) HCV RNA positive and 26 (20M:6F) exposed uninfected and no sequence differences were observed. The entire CD81 sequence from cDNA was obtained in 23 cases-11 RNA -ve, 5 RNA +ve and 7 EU. In 7 of the 23 cases, the nucleotides were confirmed with the genomic sequence (4 RNA -ve and 3 EU cases). No sequence variation was found in any of the patients studied by either method, including gene sections encoding the residues most important for CD81-HCV E2 binding. The LEL of CD81 is a molecule that is highly conserved. No differences in nucleotide sequence influencing susceptibility to, or outcome of HCV infection or evidence of methylation of the gene were found. J. Med. Virol. © 2013 Wiley Periodicals, Inc.
    Full-text · Article · Jan 2014 · Journal of Medical Virology
  • Source
    • "We have previously demonstrated that viral entry is a key determinant for HCV re-infection during LT and that HCV-CD81 interactions play an important role in this process [8], [46]. Moreover, we have demonstrated that receptor-specific antibodies or kinase inhibitors specifically inhibit entry of highly infectious HCV escape variants that are resistant to autologous host responses and re-infect the liver graft [8], [9], [25], [38]. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Hepatitis C virus (HCV) infection is a challenge to prevent and treat because of the rapid development of drug resistance and escape. Viral entry is required for initiation, spread, and maintenance of infection, making it an attractive target for antiviral strategies. Using genetic immunization, we produced four monoclonal antibodies (mAbs) against the HCV host entry factor CD81. The effects of antibodies on inhibition of HCV infection and dissemination were analyzed in HCV permissive human liver cell lines. The anti-CD81 mAbs efficiently inhibited infection by HCV of different genotypes as well as a HCV escape variant selected during liver transplantation and re-infecting the liver graft. Kinetic studies indicated that anti-CD81 mAbs target a post-binding step during HCV entry. In addition to inhibiting cell-free HCV infection, one antibody was also able to block neutralizing antibody-resistant HCV cell-cell transmission and viral dissemination without displaying any detectable toxicity. A novel anti-CD81 mAb generated by genetic immunization efficiently blocks HCV spread and dissemination. This antibody will be useful to further unravel the role of virus-host interactions during HCV entry and cell-cell transmission. Furthermore, this antibody may be of interest for the development of antivirals for prevention and treatment of HCV infection.
    Full-text · Article · May 2013 · PLoS ONE
Show more