F.122. Toll Like Receptor 2 Promotes Th2/Th17 Responses via TLR4 and TLR8 by Human Dendritic Cells by Abrogating the Type 1 Interferon Amplification Loop (original) (raw)
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Differential expression of Toll-like receptor 2 in human cells
Journal of Leukocyte Biology, 2001
Human Toll-like receptor 2 (TLR2) is a receptor for a variety of microbial products and mediates activation signals in cells of the innate immune system. We have investigated expression and regulation of the TLR2 protein in human blood cells and tissues by using two anti-TLR2 mAbs. Only myelomonocytic cell lines expressed surface TLR2. In tonsils, lymph nodes, and appendices, activated B-cells in germinal centers expressed TLR2. In human blood, CD14 ؉ monocytes expressed the highest level of TLR2 followed by CD15 ؉ granulocytes, and CD19 ؉ B-cells, CD3 ؉ T-cells, and CD56 ؉ NK cells did not express TLR2. The level of TLR2 on monocytes was after 20 h up-regulated by LPS, GM-CSF, IL-1, and IL-10 and down-regulated by IL-4, IFN-␥, and TNF. On purified granulocytes, LPS, GM-CSF, and TNF down-regulated, and IL-10 modestly increased TLR2 expression after 2 h. These data suggest that TLR2 protein expression in innate immune cells is differentially regulated by inflammatory mediators.
Journal of Experimental Medicine, 2002
Dendritic cells (DCs) play a crucial role in the immune responses against infections by sensing microbial invasion through toll-like receptors (TLRs). In humans, two distinct DC subsets, CD11c Ϫ plasmacytoid DCs (PDCs) and CD11c ϩ myeloid DCs (MDCs), have been identified and can respond to different TLR ligands, depending on the differential expression of cognate TLRs. In this study, we have examined the effect of TLR-7 ligands on human DC subsets. Both subsets expressed TLR-7 and could respond to TLR-7 ligands, which enhanced the survival of the subsets and upregulated the surface expression of costimulatory molecules such as CD40, CD80, and CD86. However, the cytokine induction pattern was distinct in that PDCs and MDCs produced interferon (IFN)-␣ and interleukin (IL)-12, respectively. In response to TLR-7 ligands, the Th1 cell supporting ability of both DC subsets was enhanced, depending on the cytokines the respective subsets produced. This study demonstrates that TLR-7 exerts its biological effect in a DC subset-specific manner.
Cytokine, 2013
IFNL1 (IL29), IFNL2 (IL28A) and IFNL3 (IL28B) might play important roles in anti-viral defense. IFNL3 genotypes have been shown to be associated with hepatitis C spontaneous and treatment-induced viral clearance. The effects of IFNL1, IFNL2 and IFNL3 on innate immunity including Toll-like receptor (TLR)-related pathway in human hepatocytes were examined. After G418 screening, we established the human hepatoma stable cell lines HepG2-IL28A, HepG2-IL28B, and HepG2-IL29, expressing IFNL2, IFNL3, and IFNL1 in conditioned medium, respectively, and a control cell line, HepG2-pcDNA3.1. We performed real-time RT-PCR to investigate 84 Toll-like receptor-related gene expressions in triplicate and, using ddCt methods, compared these gene expressions in each cell line. IFNL2, IFNL3 and IFNL1 were respectively detected by ELISA in HepG2-IL28A, HepG2-IL28B and HepG2-IL29. Compared to HepG2-pcDNA3.1 cells, 17 (20.2%), 11 (13.0%) and 16 genes (19.0%) were up-regulated 1.5-fold or more (p < 0.05); 10 (11.9%), 2 (2.3%) and 10 genes (11.9%) were 1.5-fold or more down-regulated (p < 0.05) in HepG2-IL28A, HepG2-IL28B and HepG2-IL29, respectively. EIF2AK2 and SARM1 were up-regulated among all cells. Of interest, TLR3, TLR4 and related molecules CXCL10 (IP10), IL6, EIF2K2, IFNB1, and IRF1, Highlights-IFNL3 (IL28B) genotypes are associated with HCV clearance.-Effects of 3 IFNLs on gene expressions in hepatocytes were examined.-Three IFNLs induced different actions on TLR-related genes.-IFNL3 induces ISGs that are associated with HCV clearance.-Three IFNLs may play different roles in liver diseases.
Distribution of Toll-like receptor 1 and Toll-like receptor 2 in human lymphoid tissue
Immunology, 2003
To determine how distinct receptors of the immune system can contribute to innate immunity, we investigated the pattern of Toll-like receptor 1 (TLR1) and TLR2 expression in human lymphoid tissue. We found that TLR1 and TLR2 were co-expressed on cells of the innate immune system, including macrophages and dendritic cells. In addition, TLR1 and TLR2 were expressed in mucosa-associated lymphoid tissue on tonsillar crypt epithelium. Of the lymphoid tissue examined, spleen expressed the highest levels of TLR2. Although TLR1- and TLR2-positive cells were in close proximity to T lymphocytes in vivo, lymphocytes themselves were devoid of TLR1 and TLR2 expression. The co-expression of TLR1 and TLR2 on myeloid cells in lymphoid tissue provides the host with the ability to respond to a variety of microbial ligands at sites conducive to the generation of an immune response.
The Journal of Immunology, 2000
Members of the Toll-like receptor (TLR) family probably play a fundamental role in pathogen recognition and activation of innate immunity. The present study used a systematic approach to analyze how different human leukocyte populations express specific transcripts for the first five characterized TLR family members. TLR1 was expressed in all leukocytes examined, including monocytes, polymorphonuclear leukocytes, T and B cells, and NK cells. In contrast TLR2, TLR4, and TLR5 were expressed in myelomonocytic elements. Exposure to bacterial products, such as LPS or lipoarabinomannan, or to proinflammatory cytokines increased TLR4 expression in monocytes and polymorphonuclear leukocytes, whereas IL-10 blocked this effect. TLR3 was only expressed in human dendritic cells (DC) wherein maturation induced by bacterial products or cytokines was associated with reduced expression. TLR3 mRNA expression was detected by in situ hybridization in DC and lymph nodes. These results demonstrate that TLR1 through TLR5 mRNAs are differentially expressed and regulated in human leukocytes. In particular, expression of TLR3 transcripts is restricted to DC that are the only elements which express the full TLR repertoire. These data suggest that TLR can be classified based on expression pattern as ubiquitous (TLR1), restricted (TLR2, TLR4, and TLR5 in myelomonocytic cells), and specific (TLR3 in DC) molecules.
Toll like Receptor 2 engagement on CD4(+) T cells promotes TH9 differentiation and function
European journal of immunology, 2017
We have recently demonstrated that mycobacterial ligands engage Toll like receptor 2 (TLR2) on CD4(+) T cells and up-regulate T-cell receptor (TCR) triggered Th1 responses in vitro and in vivo. To better understand the role of T-cell expressed TLR2 on CD4(+) T-cell differentiation and function, we conducted a gene expression analysis of murine naïve CD4(+) T-cells stimulated in the presence or absence of TLR2 co-stimulation. Unexpectedly, naïve CD4(+) T-cells co-stimulated via TLR2 showed a significant up-regulation of Il9 mRNA compared to cells co-stimulated via CD28. Under TH9 differentiation, we observed up-regulation of TH9 differentiation, evidenced by increases in both percent of IL-9 secreting cells and IL-9 in culture supernatants in the presence of TLR2 agonist both in polyclonal and Ag85B cognate peptide specific stimulations. Under non-polarizing conditions, TLR2 engagement on CD4(+) T-cells had minimal effect on IL-9 secretion and TH9 differentiation, likely due to a pro...