Abstract

We established a cold-adapted infectious bronchitis virus (BP-caKII) by passaging a field virus through specific pathogen-free embryonated eggs 20 times at 32 °C. We characterized its growth kinetics and pathogenicity in embryonated eggs, and its tropism and persistence in different tissues from chickens; then, we evaluated pathogenicity by using a new premature reproductive tract pathogenicity model. Furthermore, we determined the complete genomic sequence of BP-caKII to understand the genetic changes related to cold adaptation. According to our results, BP-caKII clustered with the KII genotype viruses K2 and KM91, and showed less pathogenicity than K2, a live attenuated vaccine strain. BP-caKII showed delayed viremia, resulting in its delayed dissemination to the kidneys and cecal tonsils compared to K2 and KM91, the latter of which is a pathogenic field strain. A comparative genomics study revealed similar nucleotide sequences between BP-caKII, K2 and KM91 but clearly showed different mutations among them. BP-caKII shared several mutations with K2 (nsp13, 14, 15 and 16) following embryo adaptation but acquired multiple additional mutations in nonstructural proteins (nsp3, 4 and 12), spike proteins and nucleocapsid proteins following cold adaptation. Thus, the establishment of BP-caKII and the identified mutations in this study may provide insight into the genetic background of embryo and cold adaptations, and the attenuation of coronaviruses.

Details

Title
Pathobiological and Genomic Characterization of a Cold-Adapted Infectious Bronchitis Virus (BP-caKII)
Author
Seung-Min, Hong 1 ; Se-Hee An 1 ; Chung-Young, Lee 1 ; Chang-Seon, Song 2 ; Kang-Seuk Choi 3   VIAFID ORCID Logo  ; Jae-Hong, Kim 4 ; Kwon, Hyuk-Joon 5   VIAFID ORCID Logo 

1  Laboratory of Avian Diseases, College of Veterinary Medicine, Seoul National University, Seoul 08826, Korea 
2  Laboratory of Avian Diseases, College of Veterinary Medicine, Konkuk University, Seoul 05029, Korea 
3  Avian Disease Division, animal and Plant Quarantine Agency, Gimcheon, Gyeongsangbuk-Do 39660, Korea 
4  Laboratory of Avian Diseases, College of Veterinary Medicine, Seoul National University, Seoul 08826, Korea; Reseach Institute for Veterinary Science, College of Veterinary Medicine, BK21 for Veterinary Science, Seoul 08826, Korea 
5  Reseach Institute for Veterinary Science, College of Veterinary Medicine, BK21 for Veterinary Science, Seoul 08826, Korea; Department of Farm Animal Medicine, College of Veterinary Medicine, Seoul National University, Seoul 08826, Korea; Farm Animal Clinical Training and Research Center, Seoul National University, Seoul 08826, Korea 
First page
652
Publication year
2018
Publication date
2018
Publisher
MDPI AG
e-ISSN
19994915
Source type
Scholarly Journal
Language of publication
English
DOI
https://doi.org/10.3390/v10110652
ProQuest document ID
2582920617
Copyright
© 2018 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/). Notwithstanding the ProQuest Terms and Conditions, you may use this content in accordance with the terms of the License.