Article Figures & Data
Figures
- FIG 1
TLR5 signaling. Flagellin binding to TLR recruits adaptor protein MyD88, leading to the activation of IRAK-1/4 and TRAF-6 and resulting in the activation of NF-κB, which induces the expression of proinflammatory cytokines.
- FIG 2
Mechanism of induction of the type of immune responses following TLR activation.
- FIG 3
TLR ligands affect many immunological processes to elicit an elevated immune response.
- FIG 4
Structure of flagellin with four major domains indicated (NCBI; GenBank accession no. KF589316).
Tables
- TABLE 1
Summary of TLR5-mediated adjuvant action of flagellated Salmonella strains
Study model Result(s) Reference Chicken kidney cells (CKC) Flagellated strains S. Enteritidis and S. Gallinarum (Fla+) induced higher levels of CXCLi2, iNOS, and IL-6; less mortality with flagellated strains 73 Chicken (in vivo) Flagellin-deficient mutants exhibited enhanced ability for systemic infections; lower levels of IL-1β and CXCLi2 than wild type 75 Chicken PBMCs TLR5-flagellin-mediated upregulation of IL-1β, IL-6, CXCLi2, and CCLi2 expression in S. Enteritidis-infected cells 74 CKC and HD11 Flagellated S. Enteritidis and S. Typhimurium induced more IL-6, CXCLi1, CXCLi2, and iNOS than nonflagellated S. Pullorum and S. Gallinarum 105 HeLa cells expressing chicken TLR5 Induced more NF-κB in response to S. Enteritidis infection in a dose- and flagellin-dependent manner 72 Chicken (in vivo) Reduced levels of IL-1β and IL-6 and enhanced ability to establish systemic infection after challenge with aflagellar S. Typhimurium 23 Intestinal epithelial cells Flagellin-deficient S. Typhimurium mutant (fliC, fljB, and flhD) failed to elicit IL-8 expression 52 - TABLE 2
Flagellin as an adjuvant in chicken: applications in vitro
Cell category Response(s) Reference Chicken PBMCs Upregulation of both IL-12 and IL-4 as well as IL-6 79 Chicken splenocytes Induction of a mixed Th1- and Th2-like response 80 Chicken heterophils Upregulation of IL-6 and CXCLi2 100 HeLa cells with chicken TLR5 Upregulation of TLR5-flagellin-mediated NF-κB expression 72 Chicken monocytes Induction of nitric oxide production 78 Chicken heterophils Increased oxidative burst; significant production of proinflammatory cytokines and chemokines 77 CEF, CKC HD11 cells Significant upregulation of IL-1β 23 Chicken heterophils Significant upregulation of IL-1β, IL-6, and IL-8 and increased oxidative burst 76 - TABLE 3
Flagellin as an adjuvant in chicken: applications in vivo
Antigen Result(s) Reference Immune-mapped protein-1 (IMP-1) of Eimeria tenella (EtIMP1) Flagellin-fused EtIMP1 elicited a stronger protective immune response; reduced mortality 83 Avian influenza virus Increased IgY and IgA 82 Salmonella enterica serovar Enteritidis Increased IgA and decreased bacterial counts 34 Campylobacter jejuni Increased Ig and decreased bacterial load 35 Salmonella enterica serovar Enteritidis Reduced mortality 81 Campylobacter jejuni Increased Ig and decreased bacterial load 101 - TABLE 4
Adjuvant effect of combinations of TLR agonists on chicken immune cells
TLR combination Cell category Result(s) Reference TLR5 and TLR4 Chicken PBMCs Synergistic upregulation of NO, IL-6, and IL-12; antagonistic downregulation of IL-4 79 TLR3 and TLR21 Chicken RBCsa Synergistic upregulation of type 1 IFNs 102 TLR3 and TLR21 Chicken monocytes Synergistic upregulation of IFN-γ and IL-10 103 TLR4 and TLR21 Chicken thrombocytes Synergistic upregulation of IL-1β, IL-6, and IL-8 104 TLR3 and TLR21 Chicken monocytes Synergistic upregulation of NO, IL-1β, IL-6, and MIP-1β 92 TLR3 and TLR21 Chicken monocytes Synergistic upregulation of NO production 94 ↵a RBCs, red blood cells.
