title: HIV-specific CD8(+) T cells produce antiviral cytokines but are impaired in cytolytic function.
abstract: The use of peptide-human histocompatibility leukocyte antigen (HLA) class I tetrameric complexes to identify antigen-specific CD8(+) T cells has provided a major development in our understanding of their role in controlling viral infections. However, questions remain about the exact function of these cells, particularly in HIV infection. Virus-specific cytotoxic T lymphocytes exert much of their activity by secreting soluble factors such as cytokines and chemokines. We describe here a method that combines the use of tetramers and intracellular staining to examine the functional heterogeneity of antigen-specific CD8(+) T cells ex vivo. After stimulation by specific peptide antigen, secretion of interferon (IFN)-gamma, tumor necrosis factor (TNF)-alpha, macrophage inflammatory protein (MIP)-1beta, and perforin is analyzed by FACS((R)) within the tetramer-positive population in peripheral blood. Using this method, we have assessed the functional phenotype of HIV-specific CD8(+) T cells compared with cytomegalovirus (CMV)-specific CD8(+) T cells in HIV chronic infection. We show that the majority of circulating CD8(+) T cells specific for CMV and HIV antigens are functionally active with regards to the secretion of antiviral cytokines in response to antigen, although a subset of tetramer-staining cells was identified that secretes IFN-gamma and MIP-1beta but not TNF-alpha. However, a striking finding is that HIV-specific CD8(+) T cells express significantly lower levels of perforin than CMV-specific CD8(+) T cells. This lack of perforin is linked with persistent CD27 expression on HIV-specific cells, suggesting impaired maturation, and specific lysis ex vivo is lower for HIV-specific compared with CMV-specific cells from the same donor. Thus, HIV-specific CD8(+) T cells are impaired in cytolytic activity.
authors.affiliation: Medical Research Council Human Immunology Unit, Institute of Molecular Medicine, John Radcliffe Hospital, Oxford OX3 9DS, United Kingdom.
authors.forename: V
authors.initials: V
authors.lastname: Appay
authors.forename: D F
authors.initials: DF
authors.lastname: Nixon
authors.forename: S M
authors.initials: SM
authors.lastname: Donahoe
authors.forename: G M
authors.initials: GM
authors.lastname: Gillespie
authors.forename: T
authors.initials: T
authors.lastname: Dong
authors.forename: A
authors.initials: A
authors.lastname: King
authors.forename: G S
authors.initials: GS
authors.lastname: Ogg
authors.forename: H M
authors.initials: HM
authors.lastname: Spiegel
authors.forename: C
authors.initials: C
authors.lastname: Conlon
authors.forename: C A
authors.initials: CA
authors.lastname: Spina
authors.forename: D V
authors.initials: DV
authors.lastname: Havlir
authors.forename: D D
authors.initials: DD
authors.lastname: Richman
authors.forename: A
authors.initials: A
authors.lastname: Waters
authors.forename: P
authors.initials: P
authors.lastname: Easterbrook
authors.forename: A J
authors.initials: AJ
authors.lastname: McMichael
authors.forename: S L
authors.initials: SL
authors.lastname: Rowland-Jones
mesh_terms: D018414:CD8-Positive T-Lymphocytes / Q000276:immunology* / Q000821:virology*; D054407:Chemokine CCL4; D002999:Clone Cells; D016207:Cytokines / Q000096:biosynthesis*; D003587:Cytomegalovirus / Q000276:immunology; D005434:Flow Cytometry; D006678:HIV / Q000276:immunology*; D015658:HIV Infections / Q000276:immunology*; D018023:HIV Seronegativity / Q000276:immunology; D015395:Histocompatibility Antigens Class I / Q000276:immunology; D006801:Humans; D007371:Interferon-gamma / Q000096:biosynthesis; D019402:Macrophage Inflammatory Proteins / Q000096:biosynthesis; D012016:Reference Values; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology* / Q000821:virology*; D014409:Tumor Necrosis Factor-alpha / Q000096:biosynthesis
chemical_list: D054407:Chemokine CCL4; D016207:Cytokines; D015395:Histocompatibility Antigens Class I; D019402:Macrophage Inflammatory Proteins; D014409:Tumor Necrosis Factor-alpha; D007371:Interferon-gamma