title: Impact of in vitro costimulation with TLR2, TLR4 and TLR9 agonists and HIV-1 on antigen-presenting cell activation.
abstract: OBJECTIVE
  HIV-1 infects several immune cells including dendritic cells (DCs) and monocytes, which contributes in both to dissemination of HIV-1 infection and induction of antiviral immunity. These cells produce high amounts of type I IFN and proinflammatory cytokines upon Toll-like receptor (TLR) stimulation. During HIV-1 infection, an altered production of proinflammatory cytokines has been reported. However, the mechanisms underlying cytokine modulation have not been well described. Here, we evaluated the production of proinflammatory cytokines and activation of myeloid and plasmacytoid DCs and monocytes costimulated in vitro with TLR agonists and HIV-1.
  
  
  METHODS
  Changes in cytokine expression by real-time PCR and activation of DCs and monocytes by flow cytometry were evaluated after costimulation with HIV-1 and TLR agonists.
  
  
  RESULTS
  We observed an upregulation of TNF-α expression after TLR4 stimulation, but a downregulation of IL-6 when TLR2/TLR9 were stimulated. Interestingly, the expression of CD80 and CD86 costimulatory molecules in monocytes and DCs were significantly increased in cells challenged with HIV-1 and TLR2/TLR4/TLR9 agonists.
  
  
  CONCLUSIONS
  This regulation of TNF-α and IL-6 production and changes in the expression of costimulatory molecules can be critical in the context of HIV-1 infection, by favoring the antigen-presenting cell activation through the stimulation of TLRs.
authors.affiliation: Grupo Inmunovirología, Facultad de Medicina, Universidad de Antioquia UdeA, Medellín, Colombia.
authors.forename: Diana Marcela
authors.initials: DM
authors.lastname: Giraldo
authors.forename: Juan Carlos
authors.initials: JC
authors.lastname: Hernandez
authors.forename: Silvio
authors.initials: S
authors.lastname: Urcuqui Inchima
mesh_terms: D000938:Antigen-Presenting Cells / Q000276:immunology*; D018122:B7-1 Antigen / Q000235:genetics; D051940:B7-2 Antigen / Q000235:genetics; D002460:Cell Line; D016207:Cytokines / Q000235:genetics* / Q000276:immunology; D003713:Dendritic Cells / Q000276:immunology* / Q000821:virology; D015536:Down-Regulation; D005434:Flow Cytometry; D015497:HIV-1 / Q000276:immunology*; D009000:Monocytes / Q000276:immunology; D060888:Real-Time Polymerase Chain Reaction; D051193:Toll-Like Receptors / Q000819:agonists*; D015854:Up-Regulation
chemical_list: D018122:B7-1 Antigen; D051940:B7-2 Antigen; D016207:Cytokines; D051193:Toll-Like Receptors