Pathogenicity and innate immune responses induced by fowl adenovirus serotype 8b in specific pathogen-free chicken

Xiaona Zhang; Liangliang Liu; Fangfang Wang; Huixin Li; Jiahui Fan; Jingjing Xie; Yaru Jiao; Zongxi Han; Deying Ma

Poultry Science (Aug 2023)

Pathogenicity and innate immune responses induced by fowl adenovirus serotype 8b in specific pathogen-free chicken

Xiaona Zhang,
Liangliang Liu,
Fangfang Wang,
Huixin Li,
Jiahui Fan,
Jingjing Xie,
Yaru Jiao,
Zongxi Han,
Deying Ma

Affiliations

Xiaona Zhang: College of Animal Science and Technology, Northeast Agricultural University, Harbin 150030, PR China; State Key Laboratory for Animal Disease Control and Prevention, Harbin Veterinary Research Institute, the Chinese Academy of Agricultural Sciences, Harbin 150069, PR China
Liangliang Liu: College of Animal Science and Technology, Northeast Agricultural University, Harbin 150030, PR China; State Key Laboratory for Animal Disease Control and Prevention, Harbin Veterinary Research Institute, the Chinese Academy of Agricultural Sciences, Harbin 150069, PR China
Fangfang Wang: State Key Laboratory for Animal Disease Control and Prevention, Harbin Veterinary Research Institute, the Chinese Academy of Agricultural Sciences, Harbin 150069, PR China
Huixin Li: State Key Laboratory for Animal Disease Control and Prevention, Harbin Veterinary Research Institute, the Chinese Academy of Agricultural Sciences, Harbin 150069, PR China
Jiahui Fan: College of Animal Science and Technology, Northeast Agricultural University, Harbin 150030, PR China; State Key Laboratory for Animal Disease Control and Prevention, Harbin Veterinary Research Institute, the Chinese Academy of Agricultural Sciences, Harbin 150069, PR China
Jingjing Xie: College of Animal Science and Technology, Northeast Agricultural University, Harbin 150030, PR China; State Key Laboratory for Animal Disease Control and Prevention, Harbin Veterinary Research Institute, the Chinese Academy of Agricultural Sciences, Harbin 150069, PR China
Yaru Jiao: College of Animal Science and Technology, Northeast Agricultural University, Harbin 150030, PR China; State Key Laboratory for Animal Disease Control and Prevention, Harbin Veterinary Research Institute, the Chinese Academy of Agricultural Sciences, Harbin 150069, PR China
Zongxi Han: State Key Laboratory for Animal Disease Control and Prevention, Harbin Veterinary Research Institute, the Chinese Academy of Agricultural Sciences, Harbin 150069, PR China
Deying Ma: College of Animal Science and Technology, Northeast Agricultural University, Harbin 150030, PR China; Corresponding author:

Journal volume & issue: Vol. 102, no. 8
p. 102846

Abstract

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ABSTRACT: Fowl adenovirus serotype 8b (FAdV-8b), as causative agent of inclusion body hepatitis (IBH), poses a great threat to the poultry industry. Considering the importance of innate immune response in host against viral infections, we investigated pathogenicity of a FAdV-8b strain HLJ/151129 in 1-mo-old specific pathogen-free (SPF) chickens and immune responses of host to FAdV-8b infection in this study. The results demonstrated that no obvious clinical signs were observed in infected birds. Neither mobility nor mortality was observed in both FAdV-8b infected and control chickens, as well. However, hepatic necrosis and a small amount of inflammatory cell infiltration were observed by pathological analysis. Viral load was detected in bursa of Fabricius, cecal tonsils, liver, heart, spleen, Harderian glands, and thymus. Virus shedding and viremia generated as early as 3 days postinfection (dpi) (9/10) and reached the peak at 7 dpi (10/10). In addition, the infected birds had developed FAdV-specific antibodies at 7 dpi, and the antibody titers reached the peak at 14 dpi. Furthermore, the results demonstrated that the mRNA expression levels of most of toll-like receptors (TLRs), most of avian β-defensins (AvBDs), and cytokines [interleukin (IL)-2, IL-6, and interferon (IFN)-γ], were significantly upregulated in most tissues at early phases of FAdV-8b infection, especially in liver and spleen. In contrast, FAdV-8b infection results in downregulation of TLR4, TLR5, and TLR21 expressions in some tissues of infected chickens. In addition, FAdV-8b infection upregulated myeloid differentiation factor 88 (MyD88), nuclear factor-kappa B (NF-κB) p65, and TIR-domain-containing adapter inducing interferon-β (TRIF) expression in some tissues, while decreased NF-κB p65 and TRIF in spleen at both 72 hpi and 21 dpi. Taken together, these results confirmed that FAdV-8b could replicate in all investigated tissues of infected birds, and then, result in production of FAdV-specific antibody titers. Meanwhile, the FAdV-8b infection induces strong innate immune responses at early stage in chickens, which may associate with the viral pathogenesis.

Published in Poultry Science

ISSN: 0032-5791 (Print); 1525-3171 (Online)
Publisher: Elsevier
Country of publisher: United States
LCC subjects: Agriculture: Animal culture
Website: https://www.journals.elsevier.com/poultry-science

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