title: Different counteracting host immune responses to clade 2.2.1.1 and 2.2.1.2 Egyptian H5N1 highly pathogenic avian influenza viruses in naïve and vaccinated chickens.
abstract: In Egypt, two distinct lineages of H5N1 highly pathogenic avian influenza (HPAI) viruses, "classic 2.2.1.2" and "variant 2.2.1.1" strains, have evolved. The underlying host immune responses counteracting these viruses in chickens remain not well understood. In the present study, the cytokine responses to a classic strain (C121) and those to a variant strain (V1063) were compared in naïve and vaccinated chickens. In naïve chickens, the C121 replicated more efficiently than the V1063. Both the C121 and the V1063 increased interferon (IFN)-γ and interleukin (IL)-10 gene expression at 48 h post inoculation (hpi) in the lung and spleen but the levels of these cytokines were lower in chickens infected with the C121 than those infected with the V1063. In contrast, in chickens vaccinated with inactivated C121-based vaccine, the C121 replicated less than the V1063. Both challenge with the C121 and that with the V1063 did not increase IFN-γ gene expression at 48 hpi; rather, the C121 increased IL-4 gene expression in the lung accompanied with lower viral titer and higher HI titers. These results suggested that the pathogenicity of HPAI viruses correlated with IFN-γ-producing helper and/or cytotoxic T cell responses in naïve chickens, whereas vaccine efficacy to HPAI viruses correlated with IL-4 producing helper T cell responses in the lung in vaccinated chickens. It implies that IL-4 in the lung, in addition to the traditional serum HI titers, could be used to screen novel vaccine strategies, such as strains, adjuvant, prime/boost protocols, against HPAI in chickens.
authors.affiliation: Reference Laboratory for Veterinary Quality Control on Poultry Production, Animal Health Research Institute, Dokki, Giza 12618, Egypt.
authors.forename: Ahmed A
authors.initials: AA
authors.lastname: Samy
authors.affiliation: Microbiology Department, Faculty of Veterinary Medicine, Cairo University, Giza 12211, Egypt.
authors.forename: Mona I
authors.initials: MI
authors.lastname: El-Enbaawy
authors.affiliation: Virology Department, Faculty of Veterinary Medicine, Cairo University, Giza 12211, Egypt.
authors.forename: Ahmed A
authors.initials: AA
authors.lastname: El-Sanousi
authors.affiliation: Reference Laboratory for Veterinary Quality Control on Poultry Production, Animal Health Research Institute, Dokki, Giza 12618, Egypt.
authors.forename: Soad A
authors.initials: SA
authors.lastname: Nasef
authors.affiliation: Reference Laboratory for Veterinary Quality Control on Poultry Production, Animal Health Research Institute, Dokki, Giza 12618, Egypt.
authors.forename: Mahmoud M
authors.initials: MM
authors.lastname: Naguib
authors.affiliation: Reference Laboratory for Veterinary Quality Control on Poultry Production, Animal Health Research Institute, Dokki, Giza 12618, Egypt; The Federal Research Institute for Animal Health, Friedrich-Loeffler Institute, Suedufer 10, D-17493 Greifswald-Insel Riems, Germany.
authors.forename: E M
authors.initials: EM
authors.lastname: Abdelwhab
authors.affiliation: Influenza and Prion Disease Research Centre, National Institute of Animal Health, National Agriculture and Food Research Organization (NARO), Tsukuba, Ibaraki 305-0856, Japan; Department of Veterinary Medicine, Iwate University, Morioka, Iwate 020-8550, Japan.
authors.forename: Hirokazu
authors.initials: H
authors.lastname: Hikono
authors.affiliation: Influenza and Prion Disease Research Centre, National Institute of Animal Health, National Agriculture and Food Research Organization (NARO), Tsukuba, Ibaraki 305-0856, Japan. Electronic address: taksaito@affrc.go.jp.
authors.forename: Takehiko
authors.initials: T
authors.lastname: Saito
mesh_terms: D000818:Animals; D002645:Chickens; D016207:Cytokines / Q000276:immunology; D004534:Egypt; D005786:Gene Expression Regulation / Q000276:immunology; D006389:Hemagglutinins, Viral / Q000737:chemistry / Q000235:genetics; D053124:Influenza A Virus, H5N1 Subtype / Q000276:immunology* / Q000472:pathogenicity; D007252:Influenza Vaccines / Q000276:immunology*; D005585:Influenza in Birds / Q000276:immunology* / Q000821:virology; D008958:Models, Molecular; D011201:Poultry Diseases / Q000276:immunology* / Q000821:virology; D017434:Protein Structure, Tertiary; D013047:Specific Pathogen-Free Organisms; D014611:Vaccination / Q000662:veterinary*; D015164:Vaccines, Inactivated / Q000276:immunology
chemical_list: D016207:Cytokines; D006389:Hemagglutinins, Viral; D007252:Influenza Vaccines; D015164:Vaccines, Inactivated
keywords: Avian influenza; Chickens; Cytokine; Egypt; H5N1; Vaccine