title: Novel E2 Glycoprotein Tetramer Detects Hepatitis C Virus-Specific Memory B Cells.
abstract: Acute hepatitis C virus (HCV) infection culminates in viral persistence in the majority of cases. Abs that recognize the envelope glycoproteins E1 and E2 are generated during the late stages of acute infection, yet their contribution to spontaneous viral clearance remains controversial. Investigation of the humoral responses during acute HCV infection have been limited by the inability to directly identify and characterize HCV-specific B cells. In this study we describe the development of a novel tetramer of the E2 glycoprotein ectodomain (J6, genotype 2a strain), which allowed us to visualize E2-specific B cells longitudinally in the peripheral blood of HCV-infected individuals. HCV-specific class-switched memory B cells were detected in 3 out of 7 participants during late acute infection, with a mean frequency of 0.63% for positive samples (range 0.16-0.67%) and in 7 out of 7 participants with chronic infection with a mean frequency of 0.47% (range 0.20-0.78%). In a cross-sectional study, E2 tetramer positive population was detected in 28 out of 31 chronically infected individuals. Deep sequencing of the BCR from E2-specific class-switched memory B cells sorted from two independent participants revealed a focused repertoire suggestive of clonal selection. Tetramer-specific B cells exhibited skewed CDR3 length distribution and increased mutation frequency compared with naive B cells. This BCR profile is indicative of clonal expansion and affinity maturation. E2 tetramer allows for specific and sensitive ex vivo characterization of rare HCV-specific B cells in infected individuals, and will enable researchers to gain a better understanding of humoral immunity in HCV infection.
authors.affiliation: Centre de Recherche du Centre Hospitalier de l'Université de Montréal, Montreal, Quebec H2X 0A9, Canada.
authors.forename: Maude
authors.identifier: 0000-0001-9304-7796
authors.initials: M
authors.lastname: Boisvert
authors.affiliation: Yerkes National Primate Research Center, Emory Vaccine Center, Atlanta, GA 30329.
authors.forename: Wanrui
authors.identifier: 0000-0002-0810-685X
authors.initials: W
authors.lastname: Zhang
authors.affiliation: Yerkes National Primate Research Center, Emory Vaccine Center, Atlanta, GA 30329.
authors.forename: Elizabeth J
authors.initials: EJ
authors.lastname: Elrod
authors.affiliation: Research Institute of the McGill University Health Centre, Montreal, Quebec H4A 3J1, Canada.|Division of Experimental Medicine, McGill University, Montreal, Quebec H3A 1A3, Canada.
authors.forename: Nicole F
authors.initials: NF
authors.lastname: Bernard
authors.affiliation: Centre de Recherche du Centre Hospitalier de l'Université de Montréal, Montreal, Quebec H2X 0A9, Canada.|Département de Médecine, Faculté de Médecine, Université de Montréal, Montreal, Quebec H3T 1J4, Canada.
authors.forename: Jean-Pierre
authors.identifier: 0000-0002-9544-2615
authors.initials: JP
authors.lastname: Villeneuve
authors.affiliation: Centre de Recherche du Centre Hospitalier de l'Université de Montréal, Montreal, Quebec H2X 0A9, Canada.|Département de Médecine Familiale et de Médecine D'Urgence, Faculté de Médecine, Université de Montréal, Montreal, Quebec H3T 1J4, Canada.
authors.forename: Julie
authors.initials: J
authors.lastname: Bruneau
authors.affiliation: Center for Advanced Biotechnology and Medicine, Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, NJ 08854; and.
authors.forename: Joseph
authors.initials: J
authors.lastname: Marcotrigiano
authors.affiliation: Centre de Recherche du Centre Hospitalier de l'Université de Montréal, Montreal, Quebec H2X 0A9, Canada; naglaa.shoukry@umontreal.ca arash.grakoui@emory.edu.|Département de Médecine, Faculté de Médecine, Université de Montréal, Montreal, Quebec H3T 1J4, Canada.
authors.forename: Naglaa H
authors.identifier: 0000-0002-8817-8238
authors.initials: NH
authors.lastname: Shoukry
authors.affiliation: Yerkes National Primate Research Center, Emory Vaccine Center, Atlanta, GA 30329; naglaa.shoukry@umontreal.ca arash.grakoui@emory.edu.|Division of Infectious Diseases, Department of Medicine, Emory University School of Medicine, Atlanta, GA 30329.
authors.forename: Arash
authors.initials: A
authors.lastname: Grakoui
mesh_terms: D000328:Adult; D001402:B-Lymphocytes / Q000276:immunology* / Q000821:virology; D003430:Cross-Sectional Studies; D005260:Female; D057809:HEK293 Cells; D016174:Hepacivirus / Q000276:immunology*; D006526:Hepatitis C / Q000175:diagnosis* / Q000276:immunology; D006801:Humans; D056724:Immunity, Humoral; D007156:Immunologic Memory; D007159:Immunologic Tests / Q000379:methods*; D008297:Male; D011485:Protein Binding; D015202:Protein Engineering; D014759:Viral Envelope Proteins / Q000235:genetics / Q000276:immunology / Q000378:metabolism*
chemical_list: D014759:Viral Envelope Proteins; C091015:glycoprotein E2, Hepatitis C virus