title: Specialization of Hepatitis C Virus Envelope Glycoproteins for B Lymphocytes in Chronically Infected Patients.
abstract: Hepatitis C virus (HCV) productively infects hepatocytes. Virion surface glycoproteins E1 and E2 play a major role in this restricted cell tropism by mediating virus entry into particular cell types. However, several pieces of evidence have suggested the ability of patient-derived HCV particles to infect peripheral blood mononuclear cells. The viral determinants and mechanisms mediating such events remain poorly understood. Here, we aimed at isolating viral determinants of HCV entry into B lymphocytes. For this purpose, we constructed a library of full E1E2 sequences isolated from serum and B lymphocytes of four chronically infected patients. We observed a strong phylogenetic compartmentalization of E1E2 sequences isolated from B lymphocytes in one patient, indicating that E1E2 glycoproteins can represent important mediators of the strong segregation of two specialized populations in some patients. Most of the E1E2 envelope glycoproteins were functional and allowed transduction of hepatocyte cell lines using HCV-derived pseudoparticles. Strikingly, introduction of envelope glycoproteins isolated from B lymphocytes into the HCV JFH-1 replicating virus switched the entry tropism of this nonlymphotropic virus from hepatotropism to lymphotropism. Significant detection of viral RNA and viral proteins within B cells was restricted to infections with JFH-1 harboring E1E2 from lymphocytes and depended on an endocytic, pH-dependent entry pathway. Here, we achieved for the first time the isolation of HCV viral proteins carrying entry-related lymphotropism determinants. The identification of genetic determinants within E1E2 represents a first step for a better understanding of the complex relationship between HCV infection, viral persistence, and extrahepatic disorders.
  
  
  OBJECTIVE
  Hepatitis C virus (HCV) mainly replicates within the liver. However, it has been shown that patient-derived HCV particles can slightly infect lymphocytes in vitro and in vivo, highlighting the existence of lymphotropism determinants within HCV viral proteins. We isolated HCV envelope glycoproteins from patient B lymphocytes that conferred to a nonlymphotropic HCV the ability to enter B cells, thus providing a platform for characterization of HCV entry into lymphocytes. This unusual tropism was accompanied by a loss of entry function into hepatocytes, suggesting that HCV lymphotropic variants likely constitute a distinct but parallel source for viral persistence and immune escape within chronically infected patients. Moreover, the level of genetic divergence of B-cell-derived envelopes correlated with their degree of lymphotropism, underlining a long-term specialization of some viral populations for B-lymphocytes. Consequently, the clearance of both hepatotropic and nonhepatotropic HCV populations may be important for effective treatment of chronically infected patients.
authors.affiliation: CIRI, International Center for Infectiology Research, Team EVIR, Université de Lyon, Lyon, France INSERM, U1111, Lyon, France Ecole Normale Supérieure de Lyon, Lyon, France Université Claude Bernard Lyon 1, Centre International de Recherche en Infectiologie, Lyon, France CNRS, UMR5308, Lyon, France LabEx Ecofect, Université de Lyon, Lyon, France CNRS, UMR 5557 Microbial Ecology, Microbial Dynamics and Viral Transmission team; Université Claude Bernard Lyon 1, Université de Lyon, Lyon, France.
authors.forename: Florian
authors.initials: F
authors.lastname: Douam
authors.affiliation: CNRS, UMR3525, Microbial Evolutionary Genomics, Institut Pasteur, Université Pierre et Marie Curie, Cellule Pasteur UPMC, Paris, France.
authors.forename: Louis-Marie
authors.initials: LM
authors.lastname: Bobay
authors.affiliation: CIRI, International Center for Infectiology Research, Team EVIR, Université de Lyon, Lyon, France INSERM, U1111, Lyon, France Ecole Normale Supérieure de Lyon, Lyon, France Université Claude Bernard Lyon 1, Centre International de Recherche en Infectiologie, Lyon, France CNRS, UMR5308, Lyon, France.
authors.forename: Guillemette
authors.initials: G
authors.lastname: Maurin
authors.affiliation: CIRI, International Center for Infectiology Research, Team EVIR, Université de Lyon, Lyon, France INSERM, U1111, Lyon, France Ecole Normale Supérieure de Lyon, Lyon, France Université Claude Bernard Lyon 1, Centre International de Recherche en Infectiologie, Lyon, France CNRS, UMR5308, Lyon, France.
authors.forename: Judith
authors.initials: J
authors.lastname: Fresquet
authors.affiliation: CIRI, International Center for Infectiology Research, Team EVIR, Université de Lyon, Lyon, France INSERM, U1111, Lyon, France Ecole Normale Supérieure de Lyon, Lyon, France Université Claude Bernard Lyon 1, Centre International de Recherche en Infectiologie, Lyon, France CNRS, UMR5308, Lyon, France.
authors.forename: Noémie
authors.initials: N
authors.lastname: Calland
authors.affiliation: INRA, UMR754, ENVL, Rétrovirus et Pathologie Comparée, Université Claude Bernard Lyon 1, Université de Lyon, Lyon, France.
authors.forename: Carine
authors.initials: C
authors.lastname: Maisse
authors.affiliation: UMR913, Institut des Maladies de l'Appareil Digestif (IMAD), Faculté de Médecine, INSERM, Nantes, France.
authors.forename: Tony
authors.initials: T
authors.lastname: Durand
authors.affiliation: CIRI, International Center for Infectiology Research, Team EVIR, Université de Lyon, Lyon, France INSERM, U1111, Lyon, France Ecole Normale Supérieure de Lyon, Lyon, France Université Claude Bernard Lyon 1, Centre International de Recherche en Infectiologie, Lyon, France CNRS, UMR5308, Lyon, France LabEx Ecofect, Université de Lyon, Lyon, France.
authors.forename: François-Loïc
authors.initials: FL
authors.lastname: Cosset
authors.affiliation: INSERM, U955, Groupe Hospitalier Universitaire Albert Chenevier-Henri Mondor, Créteil, France.
authors.forename: Cyrille
authors.initials: C
authors.lastname: Féray
authors.affiliation: CIRI, International Center for Infectiology Research, Team EVIR, Université de Lyon, Lyon, France INSERM, U1111, Lyon, France Ecole Normale Supérieure de Lyon, Lyon, France Université Claude Bernard Lyon 1, Centre International de Recherche en Infectiologie, Lyon, France CNRS, UMR5308, Lyon, France CNRS, UMR 5557 Microbial Ecology, Microbial Dynamics and Viral Transmission team; Université Claude Bernard Lyon 1, Université de Lyon, Lyon, France dimitri.lavillette@univ-lyon1.fr.
authors.forename: Dimitri
authors.initials: D
authors.lastname: Lavillette
mesh_terms: D001402:B-Lymphocytes / Q000821:virology*; D002460:Cell Line; D016174:Hepacivirus / Q000302:isolation & purification / Q000502:physiology*; D019698:Hepatitis C, Chronic / Q000821:virology*; D022781:Hepatocytes / Q000821:virology; D006801:Humans; D014161:Transduction, Genetic; D014759:Viral Envelope Proteins / Q000378:metabolism*; D056189:Viral Tropism; D053586:Virus Internalization
chemical_list: C087035:E1 protein, Hepatitis C virus; D014759:Viral Envelope Proteins; C091015:glycoprotein E2, Hepatitis C virus