title: Characterization of Lassa virus cell entry and neutralization with Lassa virus pseudoparticles.
abstract: The cell entry and humoral immune response of the human pathogen Lassa virus (LV), a biosafety level 4 (BSL4) Old World arenavirus, are not well characterized. LV pseudoparticles (LVpp) are a surrogate model system that has been used to decipher factors and routes involved in LV cell entry under BSL2 conditions. Here, we describe LVpp, which are highly infectious, with titers approaching those obtained with pseudoparticles displaying G protein of vesicular stomatitis virus and their the use for the characterization of LV cell entry and neutralization. Upon cell attachment, LVpp utilize endocytic vesicles for cell entry as described for many pH-dependent viruses. However, the fusion of the LV glycoproteins is activated at unusually low pH values, with optimal fusion occurring between pH 4.5 and 3, a pH range at which fusion characteristics of viral glycoproteins have so far remained largely unexplored. Consistent with a shifted pH optimum for fusion activation, we found wild-type LV and LVpp to display a remarkable resistance to exposure to low pH. Finally, LVpp allow the fast and quantifiable detection of neutralizing antibodies in human and animal sera and will thus facilitate the study of the humoral immune response in LV infections.
authors.affiliation: Université de Lyon, UCB-Lyon 1, IFR128, INSERM, U758, and Ecole Normale Supérieure de Lyon, Lyon F-69007, France. flcosset@ens-lyon.fr
authors.forename: François-Loic
authors.initials: FL
authors.lastname: Cosset
authors.forename: Philippe
authors.initials: P
authors.lastname: Marianneau
authors.forename: Geraldine
authors.initials: G
authors.lastname: Verney
authors.forename: Fabrice
authors.initials: F
authors.lastname: Gallais
authors.forename: Noel
authors.initials: N
authors.lastname: Tordo
authors.forename: Eve-Isabelle
authors.initials: EI
authors.lastname: Pécheur
authors.forename: Jan
authors.initials: J
authors.lastname: ter Meulen
authors.forename: Vincent
authors.initials: V
authors.lastname: Deubel
authors.forename: Birke
authors.initials: B
authors.lastname: Bartosch
mesh_terms: D000818:Animals; D000914:Antibodies, Viral / Q000097:blood; D002460:Cell Line; D004705:Endocytosis; D011992:Endosomes / Q000821:virology; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007836:Lassa virus / Q000276:immunology* / Q000502:physiology*; D009500:Neutralization Tests; D022701:Virosomes / Q000276:immunology*; D053586:Virus Internalization
chemical_list: D000914:Antibodies, Viral; D022701:Virosomes