title: Ex vivo analysis of human memory CD4 T cells specific for hepatitis C virus using MHC class II tetramers.
abstract: Containment of hepatitis C virus (HCV) and other chronic human viral infections is associated with persistence of virus-specific CD4 T cells, but ex vivo characterization of circulating CD4 T cells has not been achieved. To further define the phenotype and function of these cells, we developed a novel approach for the generation of tetrameric forms of MHC class II/peptide complexes that is based on the cellular peptide-exchange mechanism. HLA-DR molecules were expressed as precursors with a covalently linked CLIP peptide, which could be efficiently exchanged with viral peptides following linker cleavage. In subjects who spontaneously resolved HCV viremia, but not in those with chronic progressive infection, HCV tetramer-labeled cells could be isolated by magnetic bead capture despite very low frequencies (1:1,200 to 1:111,000) among circulating CD4 T cells. These T cells expressed a set of surface receptors (CCR7+CD45RA-CD27+) indicative of a surveillance function for secondary lymphoid structures and had undergone significant in vivo selection since they utilized a restricted Vbeta repertoire. These studies demonstrate a relationship between clinical outcome and the presence of circulating CD4 T cells directed against this virus. Moreover, they show that rare populations of memory CD4 T cells can be studied ex vivo in human diseases.
authors.affiliation: Howard Hughes Medical Institute, Partners AIDS Research Center, Boston, Massachusetts, USA.
authors.forename: Cheryl L
authors.initials: CL
authors.lastname: Day
authors.forename: Nilufer P
authors.initials: NP
authors.lastname: Seth
authors.forename: Michaela
authors.initials: M
authors.lastname: Lucas
authors.forename: Heiner
authors.initials: H
authors.lastname: Appel
authors.forename: Laurent
authors.initials: L
authors.lastname: Gauthier
authors.forename: Georg M
authors.initials: GM
authors.lastname: Lauer
authors.forename: Gregory K
authors.initials: GK
authors.lastname: Robbins
authors.forename: Zbigniew M
authors.initials: ZM
authors.lastname: Szczepiorkowski
authors.forename: Deborah R
authors.initials: DR
authors.lastname: Casson
authors.forename: Raymond T
authors.initials: RT
authors.lastname: Chung
authors.forename: Shannon
authors.initials: S
authors.lastname: Bell
authors.forename: Gillian
authors.initials: G
authors.lastname: Harcourt
authors.forename: Bruce D
authors.initials: BD
authors.lastname: Walker
authors.forename: Paul
authors.initials: P
authors.lastname: Klenerman
authors.forename: Kai W
authors.initials: KW
authors.lastname: Wucherpfennig
mesh_terms: D000818:Animals; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology* / Q000378:metabolism; D005802:Genes, MHC Class II; D006684:HLA-DR Antigens / Q000276:immunology*; D016174:Hepacivirus / Q000276:immunology*; D006526:Hepatitis C / Q000276:immunology; D006801:Humans; D007156:Immunologic Memory; D010455:Peptides / Q000737:chemistry / Q000378:metabolism; D011948:Receptors, Antigen, T-Cell / Q000276:immunology / Q000378:metabolism; D014764:Viral Proteins / Q000737:chemistry / Q000378:metabolism; D014766:Viremia / Q000276:immunology
chemical_list: D006684:HLA-DR Antigens; D010455:Peptides; D011948:Receptors, Antigen, T-Cell; D014764:Viral Proteins