title: Sensing of HIV-1 Infection in Tzm-bl Cells with Reconstituted Expression of STING.
abstract: Production of proinflammatory cytokines indicative of potent recognition by the host innate immune system has long been recognized as a hallmark of the acute phase of HIV-1 infection. The first components of the machinery by which primary HIV target cells sense infection have recently been described; however, the mechanistic dissection of innate immune recognition and viral evasion would be facilitated by an easily accessible cell line model. Here we describe that reconstituted expression of the innate signaling adaptor STING enhanced the ability of the well-established HIV reporter cell line Tzm-bl to sense HIV infection and to convert this information into nuclear translocation of IRF3 as well as expression of cytokine mRNA. STING-dependent immune sensing of HIV-1 required virus entry and reverse transcription but not genome integration. Particularly efficient recognition was observed for an HIV-1 variant lacking expression of the accessory protein Vpr, suggesting a role of the viral protein in circumventing STING-mediated immune signaling. Vpr as well as STING significantly impacted the magnitude and breadth of the cytokine mRNA expression profile induced upon HIV-1 infection. However, cytoplasmic DNA sensing did not result in detectable cytokine secretion in this cell system, and innate immune recognition did not affect infection rates. Despite these deficits in eliciting antiviral effector functions, these results establish Tzm-bl STING and Tzm-bl STING IRF3.GFP cells as useful tools for studies aimed at dissecting mechanisms and regulation of early innate immune recognition of HIV infection.
  
  
  OBJECTIVE
  Cell-autonomous immune recognition of HIV infection was recently established as an important aspect by which the host immune system attempts to fend off HIV-1 infection. Mechanistic studies on host cell recognition and viral evasion are hampered by the resistance of many primary HIV target cells to detailed experimental manipulation. We describe here that expression of the signaling adaptor STING renders the well-established HIV reporter cell line Tzm-bl competent for innate recognition of HIV infection. Key characteristics reflected in this cell model include nuclear translocation of IRF3, expression of a broad range of cytokine mRNAs, and an antagonistic activity of the HIV-1 protein Vpr. These results establish Tzm-bl STING and Tzm-bl STING IRF3.GFP cells as a useful tool for studies of innate recognition of HIV infection.
authors.affiliation: Department of Infectious Diseases, Integrative Virology, University Hospital Heidelberg, Heidelberg, Germany.
authors.forename: Maud
authors.initials: M
authors.lastname: Trotard
authors.affiliation: Department of Infectious Diseases, Integrative Virology, University Hospital Heidelberg, Heidelberg, Germany.
authors.forename: Nikolaos
authors.initials: N
authors.lastname: Tsopoulidis
authors.affiliation: Department of Infectious Diseases, Integrative Virology, University Hospital Heidelberg, Heidelberg, Germany German Center for Infection Research, Heidelberg University, Heidelberg. Germany.
authors.forename: Nadine
authors.initials: N
authors.lastname: Tibroni
authors.affiliation: Research Group Dynamics of Early Viral Infection and the Innate Antiviral Response, Division Virus-Associated Carcinogenesis, German Cancer Research Center (DKFZ), Heidelberg, Germany.
authors.forename: Joschka
authors.initials: J
authors.lastname: Willemsen
authors.affiliation: Research Group Dynamics of Early Viral Infection and the Innate Antiviral Response, Division Virus-Associated Carcinogenesis, German Cancer Research Center (DKFZ), Heidelberg, Germany.
authors.forename: Marco
authors.initials: M
authors.lastname: Binder
authors.affiliation: Department of Infectious Diseases, Molecular Virology, University of Heidelberg, Heidelberg, Germany.
authors.forename: Alessia
authors.initials: A
authors.lastname: Ruggieri
authors.affiliation: Department of Infectious Diseases, Integrative Virology, University Hospital Heidelberg, Heidelberg, Germany German Center for Infection Research, Heidelberg University, Heidelberg. Germany oliver.fackler@med.uni-heidelberg.de.
authors.forename: Oliver T
authors.initials: OT
authors.lastname: Fackler
mesh_terms: D002460:Cell Line; D016207:Cytokines / Q000096:biosynthesis / Q000235:genetics; D015870:Gene Expression; D015497:HIV-1 / Q000254:growth & development* / Q000276:immunology*; D054884:Host-Pathogen Interactions; D006801:Humans; D057131:Immune Evasion; D050838:Interferon Regulatory Factor-3 / Q000378:metabolism; D008565:Membrane Proteins / Q000096:biosynthesis* / Q000235:genetics; D021381:Protein Transport; D054325:vpr Gene Products, Human Immunodeficiency Virus / Q000235:genetics / Q000378:metabolism; D000099197:STING Protein
chemical_list: D016207:Cytokines; D050838:Interferon Regulatory Factor-3; D008565:Membrane Proteins; D054325:vpr Gene Products, Human Immunodeficiency Virus; C494232:IRF3 protein, human; C532857:STING1 protein, human; D000099197:STING Protein; C514912:vpr protein, Human immunodeficiency virus 1