title: [Role of Toll-like receptor 7 in the production of inflammatory cytokines in EV-A71-infected human Jurkat T cells].
abstract: OBJECTIVE
  To investigate the expression of Toll-like receptor (TLR) mRNA in enterovirus 71(EV-A71) infected human Jurkat T cells and clarify the role of TLRs in the pathogenesis of EV-A71 infection-induced inflammation.
  
  
  METHODS
  EV-A71 strains were isolated from feces of children patients with hand, foot and mouth disease in 2014 by Shenzhen Center for Disease Control and Prevention. Human Jurkat T cells were infected with 200 μl EV-A71 at 10(3) cell culture infective dose 50%(CCID50)/ml. The expression of TLR1-TLR10 mRNA in human Jurkat T cells was assessed at different exposure time by RT-PCR. Levels of TLR7 mRNA expression were detected by real-time PCR, and levels of myeloid differentiation factor 88 (MyD88) by western blot. The cytokine secretion of interleukin (IL)-6, IL-8 and Tumor Necrosis Factor α (TNF-α) was analyzed by ELISA assay.
  
  
  RESULTS
  The relative expression level of TLR7 mRNA in human Jurkat T cells were 1.26 ± 0.15, 1.75 ± 0.20, 2.26 ± 0.23 and 3.74 ± 0.62 in 6, 12, 24 and 48 h after EV-A71 infection, which the differences were significant with mock-infected group(t values were -2.96, -6.38, -9.57, -7.71; P<0.05). Western blot showed that the protein expression levels of MyD88 had increased 1.34 times and 2.17 times in 24 h and 48 h after EV-A71 infection compared with mock-infected group. After infected for 24 h and 48 h, the levels of IL-6 were (302.86 ± 38.11), (179.70 ± 14.50) pg/ml, which were significantly higher than mock-infected group (176.42 ± 9.60), (179.70 ± 14.50) pg/ml (t values were -5.57, -18.54, P<0.05). The levels of TNF-α in EV-A71 infected group (100.81 ± 9.81) pg/ml was higher than that in mock-infected group (56.19 ± 6.94) pg/ml, and the difference was significant (t=-6.43, P=0.003).
  
  
  CONCLUSIONS
  TLR7 is the main pattern recognition receptor responsible for EV-A71 recognition in immune cells, which then leads to the activation of TLR7 downstream signaling and the production of proinflammatory cytokines.
authors.affiliation: Department of Microbiological Laboratory, Baoan Center for Disease Control and Prevention, Shenzhen 518101, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Chi
authors.forename: Yaqing
authors.initials: Y
authors.lastname: He
authors.forename: Guangqing
authors.initials: G
authors.lastname: Yu
authors.forename: Lei
authors.initials: L
authors.lastname: Lei
mesh_terms: D015153:Blotting, Western; D002460:Cell Line; D029821:Enterovirus A, Human / Q000472:pathogenicity*; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D015850:Interleukin-6 / Q000378:metabolism*; D016209:Interleukin-8 / Q000378:metabolism*; D053594:Myeloid Differentiation Factor 88 / Q000378:metabolism; D060888:Real-Time Polymerase Chain Reaction; D013601:T-Lymphocytes / Q000276:immunology* / Q000821:virology; D051199:Toll-Like Receptor 7 / Q000276:immunology*; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism*
chemical_list: C508600:IL6 protein, human; D015850:Interleukin-6; D016209:Interleukin-8; C507779:MYD88 protein, human; D053594:Myeloid Differentiation Factor 88; C495348:TLR7 protein, human; D051199:Toll-Like Receptor 7; D014409:Tumor Necrosis Factor-alpha