title: Reduction of avian influenza virus shedding by administration of Toll-like receptor ligands to chickens.
abstract: Avian influenza viruses (AIV) are of concern to the poultry industry. Outbreaks of AIV highlight the urgent need for effective control measures. Prophylactic strategies should be explored that rapidly elicit immunity against the virus. Toll-like receptors (TLRs) are innate immune molecules that can induce anti-viral responses, therefore the application of TLR ligands as prophylactic agents in chickens is gaining more attention. We hypothesized that treatment of chickens with TLR ligands reduces the shedding of AIV from infected birds. In addition, the effects of TLR ligand dose and route of administration on the efficiency of TLR ligands to reduce AIV shedding were examined. Chickens were treated with TLR2, 4, 7 and 21 ligands using different doses and routes of administration, 18h before AIV infection. Moreover, the expression of several candidate genes, such as type I interferons, PKR, OAS, viperin and IFITM3 was quantified at 3, 8 and 18h post-treatment with TLR ligands. The results revealed that route of administration and dosage affect the efficacy of TLR ligands to reduce virus shedding. Furthermore, varying effects were observed when different ligands were applied. Our results demonstrated that all TLR ligand treatments reduced AIV shedding, with the CpG-ODN 1826 being the most efficacious to reduce oral virus shedding, whereas LPS from Escherichia coli 026:B6 resulted in the largest reduction in cloacal virus shedding. Moreover, TLR ligands induced the expression of genes involved in antiviral responses such as type I interferons and interferon-stimulated genes in chicken trachea and cecal tonsils. These results raise the possibility of treatment of chickens with TLR ligands as anti-viral agents.
authors.affiliation: Department of Pathobiology, University of Guelph, Guelph, ON N1G 2W1, Canada.
authors.forename: Neda
authors.initials: N
authors.lastname: Barjesteh
authors.affiliation: Department of Pathobiology, University of Guelph, Guelph, ON N1G 2W1, Canada.
authors.forename: Bahram
authors.initials: B
authors.lastname: Shojadoost
authors.affiliation: Ceva Animal Health, Guelph, Ontario N1K 1A8, Canada.
authors.forename: Jennifer T
authors.initials: JT
authors.lastname: Brisbin
authors.affiliation: Department of Pathobiology, University of Guelph, Guelph, ON N1G 2W1, Canada.
authors.forename: Mehdi
authors.initials: M
authors.lastname: Emam
authors.affiliation: Department of Pathobiology, University of Guelph, Guelph, ON N1G 2W1, Canada.
authors.forename: Douglas C
authors.initials: DC
authors.lastname: Hodgins
authors.affiliation: Department of Pathobiology, University of Guelph, Guelph, ON N1G 2W1, Canada.
authors.forename: Éva
authors.initials: É
authors.lastname: Nagy
authors.affiliation: Department of Pathobiology, University of Guelph, Guelph, ON N1G 2W1, Canada. Electronic address: shayan@uoguelph.ca.
authors.forename: Shayan
authors.initials: S
authors.lastname: Sharif
mesh_terms: D000276:Adjuvants, Immunologic / Q000008:administration & dosage*; D000818:Animals; D002432:Cecum / Q000276:immunology; D002645:Chickens; D002988:Cloaca / Q000821:virology; D020869:Gene Expression Profiling; D005585:Influenza in Birds / Q000821:virology*; D009055:Mouth / Q000821:virology; D013997:Time Factors; D051193:Toll-Like Receptors / Q000819:agonists*; D014132:Trachea / Q000276:immunology; D017201:Virus Shedding
chemical_list: D000276:Adjuvants, Immunologic; D051193:Toll-Like Receptors
keywords: Avian influenza virus; Immune response; Immunity; Interferon stimulated genes; Interferons; Toll-like receptor ligands; Virus shedding