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Soluble flagellin coimmunization attenuates Th1 priming to Salmonella and clearance by modulating dendritic cell activation and cytokine production |
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| Authors: | Adriana Flores‐Langarica Saeeda Bobat Jennifer L. Marshall Juan Carlos Yam‐Puc Charlotte N. Cook Karine Serre Robert A. Kingsley Leopoldo Flores‐Romo Satoshi Uematsu Shizuo Akira Ian R. Henderson Kai M. Toellner Adam F. Cunningham |
| Affiliation: | 1. Division of Immunity and Infection, Institute of Biomedical Research, University of Birmingham, Birmingham, UK;2. Deparamento de Biologia Celular. CINVESTAV. Mexico, D.F. Mexico;3. Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Lisbon, Portugal;4. The Institute of Food Research, Norwich Research Park, Norwich, UK;5. International Research and Development Centre for Mucosal Vaccine, Institute for Medical Science, The University of Tokyo, Tokyo, Japan;6. Laboratory of Host Defense, World Premier International Immunology Frontier Research Center, Osaka University, Suita Osaka, Japan;7. Department of Host Defense, Research Institute for Microbial Diseases, Osaka University, Suita Osaka, Japan |
| Abstract: | Soluble flagellin (sFliC) from Salmonella Typhimurium (STm) can induce a Th2 response to itself and coadministered antigens through ligation of TLR5. These properties suggest that sFliC could potentially modulate responses to Th1 antigens like live STm if both antigens are given concurrently. After coimmunization of mice with sFliC and STm there was a reduction in Th1 T cells (T‐bet+IFN‐γ+ CD4 T cells) compared to STm alone and there was impaired clearance of STm. In contrast, there was no significant defect in the early extrafollicular B‐cell response to STm. These effects are dependent upon TLR5 and flagellin expression by STm. The mechanism for these effects is not related to IL‐4 induced to sFliC but rather to the effects of sFliC coimmunization on DCs. After coimmunization with STm and sFliC, splenic DCs had a lower expression of costimulatory molecules and profoundly altered kinetics of IL‐12 and TNFα expression. Ex vivo experiments using in vivo conditioned DCs confirmed the effects of sFliC were due to altered DC function during a critical window in the coordinated interplay between DCs and naïve T cells. This has marked implications for understanding how limits in Th1 priming can be achieved during infection‐induced, Th1‐mediated inflammation. |
| Keywords: | Dendritic cell activation Flagellin Priming Salmonella Typhimurium Th1 cells |