title: Impact of changes in antigen level on CD38/PD-1 co-expression on HIV-specific CD8 T cells in chronic, untreated HIV-1 infection.
abstract: Excessive immune activation is a hallmark of chronic uncontrolled HIV infection. During the past years, growing evidence suggests that immune inhibitory signals also play an important role in progressive disease. However, the relationship between positive and negative immune signals on HIV-specific CD8 T cells has not been studied in detail so far in chronic HIV-1 infection. In this study, the expression of markers of positive (CD38) and negative (PD-1) immune signals on virus-specific CD8 T cells in chronic, untreated HIV-1 infection was evaluated using intracellular cytokine staining. Viral escape mutations were assessed by autologous virus sequence analysis and subsequent peptide titration assays. Single-epitope CD8 T-cell responses toward Gag, Pol, and Nef were compared in 12 HIV-1 controllers (viral load <5,000 cp/ml) and 12 HIV-1 progressors (viral load >50,000 cp/ml) and a highly significant increase of CD38/PD-1 co-expression on virus-specific CD8 T cells in progressors was found (P < 0.0001). The level of CD38/PD-1 co-expression was independent of epitope specificity. Longitudinal follow-up revealed a clear drop in CD38/PD-1 co-expression on virus-specific CD8 T cells after the suppression of antigen following either viral escape mutation or the initiation of HAART (P = 0.004). Antigen persistence with a fluctuating viral load revealed stable levels of CD38/PD-1 co-expression whereas significant rises in viral load were accompanied or even preceded by substantial increases in CD38/PD-1 co-expression. The CD38/PD-1 phenotype clearly distinguishes HIV-specific CD8 T-cell responses between controllers and progressors. Whether it plays a causative role in disease progression remains debatable. J. Med. Virol. 82:358-370, 2010. (c) 2010 Wiley-Liss, Inc.
authors.affiliation: Medical Poliklinik, Ludwig-Maximilians-University, Munich, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Vollbrecht
authors.forename: Heike
authors.initials: H
authors.lastname: Brackmann
authors.forename: Nadja
authors.initials: N
authors.lastname: Henrich
authors.forename: Joerg
authors.initials: J
authors.lastname: Roeling
authors.forename: Ulrich
authors.initials: U
authors.lastname: Seybold
authors.forename: Johannes R
authors.initials: JR
authors.lastname: Bogner
authors.forename: Frank D
authors.initials: FD
authors.lastname: Goebel
authors.forename: Rika
authors.initials: R
authors.lastname: Draenert
mesh_terms: D051997:ADP-ribosyl Cyclase 1 / Q000096:biosynthesis*; D000818:Animals; D015703:Antigens, CD / Q000096:biosynthesis*; D000956:Antigens, Viral / Q000276:immunology; D051017:Apoptosis Regulatory Proteins / Q000096:biosynthesis*; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology*; D015870:Gene Expression; D015658:HIV Infections / Q000276:immunology*; D015497:HIV-1 / Q000276:immunology*; D006801:Humans; D008562:Membrane Glycoproteins / Q000096:biosynthesis*; D061026:Programmed Cell Death 1 Receptor; D019562:Viral Load / Q000276:immunology
chemical_list: D015703:Antigens, CD; D000956:Antigens, Viral; D051017:Apoptosis Regulatory Proteins; D008562:Membrane Glycoproteins; C105992:PDCD1 protein, human; D061026:Programmed Cell Death 1 Receptor; C498154:CD38 protein, human; D051997:ADP-ribosyl Cyclase 1