TLR2 promotes Th2/Th17 responses via TLR4 and TLR7/8 by abrogating the type I IFN amplification loop.
TLR2 plays an important role in the removal of Gram-positive bacteria; contrastingly, it also appears to have important protective effects against unrestrained inflammation and subsequent organ injury during infection and autoimmunity. We hypothesized that TLR2 tunes the phenotype of dendritic cells (DCs) activated through other TLRs, thereby fulfilling a crucial role in the modulation of the immune response. TLR2 potently inhibited TLR4- and TLR7/8-induced cytokine production by human DCs. The inhibitory effect of TLR2 on the release of TNF-alpha but not of IL-12p70 was mediated by PI3K. TLR2 inhibits the production of IL-12p70 by dampening the type 1 IFN amplification loop. When DCs were triggered with the potent synergistic combination of LPS (TLR4) and R848 (TLR7/8) in conjunction with a TLR2 ligand, a clear shift to more Th2- and Th17-prone responses in the naive and memory T cell subpopulations was observed. This shift in T cell responses was inherent to the inability of TLR2-stimulated DCs to produce IL-12p70 and was dependent on the production of IL-1 and IL-6.
Wenink
Mark H
MH
Department of Rheumatology, Radboud University Nijmegen Medical Center, Geert Grooteplein 8, 6500 HB Nijmegen, The Netherlands. M.Wenink@reuma.umcn.nl
Santegoets
Kim C M
KC
Broen
Jacobus C A
JC
van Bon
Lenny
L
Abdollahi-Roodsaz
Shahla
S
Popa
Calin
C
Huijbens
Richard
R
Remijn
Thijs
T
Lubberts
Erik
E
van Riel
Piet L C M
PL
van den Berg
Wim B
WB
Radstake
Timothy R D J
TR
D015153:Blotting, Western; D003713:Dendritic Cells / Q000276:immunology* / Q000378:metabolism; D004797:Enzyme-Linked Immunosorbent Assay; D005434:Flow Cytometry; D006801:Humans; D007370:Interferon Type I / Q000276:immunology* / Q000378:metabolism; D007375:Interleukin-1 / Q000096:biosynthesis / Q000276:immunology; D018664:Interleukin-12 / Q000096:biosynthesis / Q000276:immunology; D020381:Interleukin-17 / Q000276:immunology / Q000378:metabolism; D015850:Interleukin-6 / Q000096:biosynthesis / Q000276:immunology; D008213:Lymphocyte Activation / Q000276:immunology; D007959:Lymphocyte Culture Test, Mixed; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction / Q000276:immunology; D016176:T-Lymphocyte Subsets / Q000276:immunology* / Q000378:metabolism; D018418:Th2 Cells / Q000276:immunology / Q000378:metabolism; D051195:Toll-Like Receptor 2 / Q000276:immunology* / Q000378:metabolism; D051197:Toll-Like Receptor 4 / Q000276:immunology* / Q000378:metabolism; D051199:Toll-Like Receptor 7 / Q000276:immunology* / Q000378:metabolism
D007370:Interferon Type I; D007375:Interleukin-1; D020381:Interleukin-17; D015850:Interleukin-6; C495342:TLR2 protein, human; C495345:TLR4 protein, human; C495348:TLR7 protein, human; D051195:Toll-Like Receptor 2; D051197:Toll-Like Receptor 4; D051199:Toll-Like Receptor 7; D018664:Interleukin-12