title: Upregulation of PD-1 expression on circulating and intrahepatic hepatitis C virus-specific CD8+ T cells associated with reversible immune dysfunction.
abstract: Infection with hepatitis C virus (HCV) is associated with persistence in the majority of individuals. We demonstrate here that the inhibitory molecule programmed death-1 (PD-1) is significantly upregulated on total and HCV-specific CD8(+) cytotoxic T lymphocytes (CTLs) in the peripheral blood and livers of patients with chronic infection compared to subjects with spontaneous HCV resolution, patients with nonviral liver disease, and normal controls. PD-1 expression on cytomegalovirus-specific CTLs also varies according to HCV status and is highest in patients with chronic infection. HCV-specific CTLs that are PD-1(high) express higher levels of the senescence marker CD57 than PD-1(low) CTLs, and CD57 expression is greater in chronic than in resolved infection. In vitro blockade of PD-1 by monoclonal antibodies specific to its ligands (PD-L1 and PD-L2) results in restoration of functional competence (proliferation and gamma interferon and interleukin-2 secretion) of HCV-specific CTLs, including those residing in the liver. This reversal of CTL exhaustion is evident even in individuals who lack HCV-specific CD4(+) T-cell help. Our data indicate that the PD-1/PD-L pathway is critical in persistent HCV infection in humans and represents a potential novel target for restoring function of exhausted HCV-specific CTLs.
authors.affiliation: Division of Gastroenterology/Hepatology, Hepatitis C Center, University of Colorado Health Sciences Center and National Jewish Hospital, Denver, CO 80262, USA.
authors.forename: Lucy
authors.initials: L
authors.lastname: Golden-Mason
authors.forename: Brent
authors.initials: B
authors.lastname: Palmer
authors.forename: Jared
authors.initials: J
authors.lastname: Klarquist
authors.forename: John A
authors.initials: JA
authors.lastname: Mengshol
authors.forename: Nicole
authors.initials: N
authors.lastname: Castelblanco
authors.forename: Hugo R
authors.initials: HR
authors.lastname: Rosen
mesh_terms: D000328:Adult; D000911:Antibodies, Monoclonal; D015703:Antigens, CD / Q000096:biosynthesis* / Q000276:immunology; D051017:Apoptosis Regulatory Proteins / Q000096:biosynthesis*; D060890:B7-H1 Antigen; D001769:Blood / Q000276:immunology; D018959:CD57 Antigens / Q000032:analysis; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology*; D049109:Cell Proliferation; D003587:Cytomegalovirus / Q000276:immunology; D003586:Cytomegalovirus Infections / Q000276:immunology; D005260:Female; D016174:Hepacivirus / Q000276:immunology*; D019698:Hepatitis C, Chronic / Q000276:immunology*; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins / Q000276:immunology; D007371:Interferon-gamma / Q000096:biosynthesis; D007376:Interleukin-2 / Q000096:biosynthesis; D008099:Liver / Q000276:immunology; D008297:Male; D008875:Middle Aged; D061027:Programmed Cell Death 1 Ligand 2 Protein; D061026:Programmed Cell Death 1 Receptor; D016176:T-Lymphocyte Subsets / Q000276:immunology*; D015854:Up-Regulation
chemical_list: D000911:Antibodies, Monoclonal; D015703:Antigens, CD; D051017:Apoptosis Regulatory Proteins; D060890:B7-H1 Antigen; C423236:CD274 protein, human; D018959:CD57 Antigens; D036341:Intercellular Signaling Peptides and Proteins; D007376:Interleukin-2; C105992:PDCD1 protein, human; C556977:PDCD1LG2 protein, human; D061027:Programmed Cell Death 1 Ligand 2 Protein; D061026:Programmed Cell Death 1 Receptor; D007371:Interferon-gamma