title: Dendritic cells infected with vpr-positive human immunodeficiency virus type 1 induce CD8+ T-cell apoptosis via upregulation of tumor necrosis factor alpha.
abstract: Human immunodeficiency virus type 1 (HIV-1) viral protein R (Vpr) plays a crucial role in viral replication and pathogenesis by inducing cell cycle arrest, apoptosis, translocation of preintegration complex, potentiation of glucocorticoid action, impairment of dendritic cell (DC) maturation, and T-cell activation. Recent studies involving the direct effects of Vpr on DCs and T cells indicated that HIV-1 containing Vpr selectively impairs phenotypic maturation, cytokine network, and antigen presentation in DCs and dysregulates costimulatory molecules and cytokine production in T cells. Here, we have further investigated the indirect effect of HIV-1 Vpr(+) virus-infected DCs on the bystander CD8(+) T-cell population. Our results indicate that HIV-1 Vpr(+) virus-infected DCs dysregulate CD8(+) T-cell proliferation and induce apoptosis. Vpr-containing virus-infected DC-mediated CD8(+) T-cell killing occurred in part through enhanced tumor necrosis factor alpha production by infected DCs and subsequent induction of death receptor signaling and activation of the caspase 8-dependent pathway in CD8(+) T cells. Collectively, these results provide evidence that Vpr could be one of the important contributors to the host immune escape by HIV-1 through its ability to dysregulate both directly and indirectly the DC biology and T-cell functions.
authors.affiliation: Department of Infectious Diseases and Microbiology, University of Pittsburgh, GSPH, 130 Desoto Street, Pittsburgh, PA 15261, USA.
authors.forename: Biswanath
authors.initials: B
authors.lastname: Majumder
authors.forename: Narasimhan J
authors.initials: NJ
authors.lastname: Venkatachari
authors.forename: Elizabeth A
authors.initials: EA
authors.lastname: Schafer
authors.forename: Michelle L
authors.initials: ML
authors.lastname: Janket
authors.forename: Velpandi
authors.initials: V
authors.lastname: Ayyavoo
mesh_terms: D017209:Apoptosis / Q000276:immunology*; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology*; D002478:Cells, Cultured; D003713:Dendritic Cells / Q000276:immunology*; D015497:HIV-1 / Q000502:physiology*; D006801:Humans; D020133:Reverse Transcriptase Polymerase Chain Reaction; D050794:STAT1 Transcription Factor / Q000378:metabolism; D015398:Signal Transduction; D013601:T-Lymphocytes / Q000166:cytology*; D014409:Tumor Necrosis Factor-alpha / Q000096:biosynthesis / Q000378:metabolism*; D015854:Up-Regulation
chemical_list: D050794:STAT1 Transcription Factor; D014409:Tumor Necrosis Factor-alpha