title: Characterization of host responses induced by Toll-like receptor ligands in chicken cecal tonsil cells.
abstract: The innate responses of cecal tonsils against invading microorganisms are mediated by conserved pattern recognition receptors (PRRs) such as the Toll-like receptors (TLRs). TLRs expressed by mammalian and avian immune system cells have the capability to recognize pathogen-associated molecular patterns (PAMPs). Although, the role of TLR ligands in innate and adaptive responses in chickens has been characterized in spleen and bursa of Fabricius, considerably less is known about responses in cecal tonsils. The aim of the current study was to assess responses of mononuclear cells from cecal tonsils to treatment with the TLR2, TLR4 and TLR21 ligands, Pam3CSK4, lipopolysaccharide (LPS), and CpG oligodeoxynucleotide (ODN), respectively. All three ligands induced significant up-regulation of interferon (IFN)-γ, interleukin (IL)-1β, IL-6 and CxCLi2/IL-8, whereas no significant changes were observed in expression of IL-13 or the antimicrobial peptides, avian β-defensin (AvBD) 1, AvBD2 and cathelicidin 3 (CATHL-3). In general, CpG ODN elicited the highest cytokine responses by cecal tonsil mononuclear cells, inducing significantly higher expression compared to LPS and Pam3CSK4, for IFNγ, IL-1β, IL-6 and CxCLi2 at various time points. These findings suggest the potential use of TLR21 ligands as mucosal vaccine adjuvants, especially in the context of pathogens of the intestinal tract.
authors.affiliation: Department of Pathobiology, Ontario Veterinary College, University of Guelph, Guelph, ON N1G 2W1, Canada; Pathology Department, Faculty of Veterinary Medicine, Beni-Suef University, Al Shamlah, 62511, Beni-Suef, Egypt.
authors.forename: Khaled
authors.initials: K
authors.lastname: Taha-Abdelaziz
authors.affiliation: Department of Pathobiology, Ontario Veterinary College, University of Guelph, Guelph, ON N1G 2W1, Canada.
authors.forename: Tamiru Negash
authors.initials: TN
authors.lastname: Alkie
authors.affiliation: Department of Pathobiology, Ontario Veterinary College, University of Guelph, Guelph, ON N1G 2W1, Canada.
authors.forename: Douglas C
authors.initials: DC
authors.lastname: Hodgins
authors.affiliation: Department of Pathobiology, Ontario Veterinary College, University of Guelph, Guelph, ON N1G 2W1, Canada.
authors.forename: Bahram
authors.initials: B
authors.lastname: Shojadoost
authors.affiliation: Department of Pathobiology, Ontario Veterinary College, University of Guelph, Guelph, ON N1G 2W1, Canada. Electronic address: shayan@uoguelph.ca.
authors.forename: Shayan
authors.initials: S
authors.lastname: Sharif
mesh_terms: D000818:Animals; D023181:Antimicrobial Cationic Peptides / Q000235:genetics; D030161:Avian Proteins / Q000276:immunology*; D002432:Cecum / Q000166:cytology / Q000276:immunology*; D002645:Chickens / Q000033:anatomy & histology / Q000235:genetics / Q000276:immunology*; D016207:Cytokines / Q000235:genetics; D015870:Gene Expression; D006790:Host-Parasite Interactions / Q000276:immunology; D018928:Immunity, Mucosal; D066298:In Vitro Techniques; D008024:Ligands; D008221:Lymphoid Tissue / Q000166:cytology / Q000276:immunology; D009838:Oligodeoxyribonucleotides / Q000276:immunology; D018417:Th1 Cells / Q000276:immunology; D018418:Th2 Cells / Q000276:immunology; D051193:Toll-Like Receptors / Q000276:immunology*
chemical_list: D023181:Antimicrobial Cationic Peptides; D030161:Avian Proteins; C408982:CPG-oligonucleotide; D016207:Cytokines; D008024:Ligands; D009838:Oligodeoxyribonucleotides; D051193:Toll-Like Receptors
keywords: Cecal tonsils; Chicken; Cytokines; Innate responses; Ligands; Toll-like receptor