title: CD25+ regulatory T cells isolated from HIV-infected individuals suppress the cytolytic and nonlytic antiviral activity of HIV-specific CD8+ T cells in vitro.
abstract: HIV infection is characterized by CD4(+) T cell depletion and progressive immune dysfunction; particularly impacted are HIV-specific T cell responses. An important component of immune-mediated control of HIV replication, killing of infected cells, appears to be impaired, in part due to poor cytolytic activity of HIV-specific cytotoxic T cells (CTL). In vitro, several functions of HIV-specific T cells, such as cytokine production, can be enhanced by the depletion of the immunosuppressive CD25(+) FoxP3(+) CD4(+) regulatory (Treg) cell subset. However, the effect of CD25(+) Treg cells on virus-specific cytolytic activity in the context of HIV or any human viral infection has not been investigated. The present study demonstrates that CD25(+) Treg cells isolated from the peripheral blood of HIV-infected subjects significantly suppress HIV Gag-specific cytolytic activity in vitro. In addition, CD25(+) Treg cells suppress effector function (coexpression of TNF-alpha and IFN-gamma) of HIV-specific CD8(+) T cells that proliferate in response to HIV antigen. Finally, the secretion of HIV-inhibitory CC-chemokines by HIV-specific and nonspecific CD8(+) T cells is significantly reduced in the presence of CD25(+) Treg cells. These data suggest that CD25(+) Treg-mediated suppression of the antiviral activity of HIV-specific CD8(+) T cells could impact the ability of HIV-infected individuals to control HIV replication in vivo.
authors.affiliation: Laboratory of Immunoregulation, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA. AKinter@niaid.nih.gov
authors.forename: Audrey L
authors.initials: AL
authors.lastname: Kinter
authors.forename: Robin
authors.initials: R
authors.lastname: Horak
authors.forename: Melanie
authors.initials: M
authors.lastname: Sion
authors.forename: Lindsey
authors.initials: L
authors.lastname: Riggin
authors.forename: Jonathan
authors.initials: J
authors.lastname: McNally
authors.forename: Yin
authors.initials: Y
authors.lastname: Lin
authors.forename: Robert
authors.initials: R
authors.lastname: Jackson
authors.forename: Angeline
authors.initials: A
authors.lastname: O'shea
authors.forename: Gregg
authors.initials: G
authors.lastname: Roby
authors.forename: Colin
authors.initials: C
authors.lastname: Kovacs
authors.forename: Mark
authors.initials: M
authors.lastname: Connors
authors.forename: Stephen A
authors.initials: SA
authors.lastname: Migueles
authors.forename: Anthony S
authors.initials: AS
authors.lastname: Fauci
mesh_terms: D018414:CD8-Positive T-Lymphocytes / Q000276:immunology / Q000821:virology*; D002450:Cell Communication / Q000276:immunology*; D015683:Gene Products, gag / Q000276:immunology; D015658:HIV Infections / Q000276:immunology*; D015497:HIV-1 / Q000276:immunology*; D006801:Humans; D016867:Immunocompromised Host / Q000276:immunology; D007371:Interferon-gamma / Q000378:metabolism; D053645:Interleukin-2 Receptor alpha Subunit; D008213:Lymphocyte Activation / Q000276:immunology; D016176:T-Lymphocyte Subsets / Q000276:immunology / Q000821:virology; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology / Q000821:virology; D050378:T-Lymphocytes, Regulatory / Q000276:immunology / Q000821:virology; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism
chemical_list: D015683:Gene Products, gag; D053645:Interleukin-2 Receptor alpha Subunit; D014409:Tumor Necrosis Factor-alpha; D007371:Interferon-gamma