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Jiang Y, Cheng X, Gao M, Yu Y, Dou X, Shen H, Tang M, Zhou S, Peng D. Two mutations on S2 subunit were critical for Vero cell tropism expansion of infectious bronchitis virus HV80. Vet Microbiol 2024; 294:110134. [PMID: 38820725 DOI: 10.1016/j.vetmic.2024.110134] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2024] [Revised: 05/23/2024] [Accepted: 05/27/2024] [Indexed: 06/02/2024]
Abstract
Infectious bronchitis virus (IBV) restricts cell tropism. Except for the Beaudette strain, other IBVs cannot infect mammalian cell lines. The limited cell tropism of other IBVs has hindered IBV vaccine development and research on the mechanisms of IBV infection. A novel Vero cell-adapted strain, HV80, has been previously reported. In this study, we constructed recombinants expressing the chimeric S glycoprotein, S1 or S2 subunit of strain H120 and demonstrated that mutations on S2 subunit are associated with the strain HV80 Vero cell adaptation. R687P or P687R substitution recombinants were constructed with the genome backbone of strains HV80 or H120. We found that the RRRR690/S motif at the S2' cleavage site is crucial to the Vero cell adaptation of strain HV80. Another six amino acid substitutions in the S2 subunit of the recombinants showed that the Q855H mutation induced syncytium formation. A transient transfection assay demonstrated the S glycoprotein with the PRRR690/S motif at the S2' cleavage site induced low-level cell-cell fusion, while H855Q substitution hindered cell-cell fusion and blocked cleavage event with S20 product. This study provides a basis for the construction of IBV recombinants capable of replicating in Vero cells, thus contributing to the advancement in the development of genetically engineered cell-based IBV vaccines.
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Affiliation(s)
- Yi Jiang
- College of Veterinary Medicine, Yangzhou University, 225009, China; Jiangsu Institute of Poultry Sciences, Yangzhou 225125, China
| | - Xu Cheng
- Jiangsu Institute of Poultry Sciences, Yangzhou 225125, China
| | - Mingyan Gao
- Jiangsu Institute of Poultry Sciences, Yangzhou 225125, China
| | - Yan Yu
- Jiangsu Institute of Poultry Sciences, Yangzhou 225125, China
| | - Xinhong Dou
- Jiangsu Institute of Poultry Sciences, Yangzhou 225125, China; Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou 225009, China
| | - Haiyu Shen
- Jiangsu Institute of Poultry Sciences, Yangzhou 225125, China; Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou 225009, China
| | - Mengjun Tang
- Jiangsu Institute of Poultry Sciences, Yangzhou 225125, China
| | - Sheng Zhou
- College of Veterinary Medicine, Qingdao Agricultural University, Qingdao 266109, China.
| | - Daxin Peng
- College of Veterinary Medicine, Yangzhou University, 225009, China; Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou 225009, China.
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Yang Q, Gong H, Liu S, Huang S, Yan W, Wang K, Li H, Lei CW, Wang HN, Yang X. Differential analysis of IBV-infected primary chicken embryonic fibroblasts and immortalized DF-1. Microbiol Spectr 2024; 12:e0240223. [PMID: 38299864 PMCID: PMC10913733 DOI: 10.1128/spectrum.02402-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2023] [Accepted: 11/30/2023] [Indexed: 02/02/2024] Open
Abstract
Infectious bronchitis virus (IBV), the causative agent of infectious bronchitis, is responsible for major economic losses in the poultry industry worldwide. While IBVs can usually be passaged in primary chicken embryonic fibroblasts (CEFs), most of the wild ones cannot adapt to passaged cell lines. In this study, the wild strain CK/CH/MY/2020 was used to infect primary CEF and immortalize DF-1 CEF cells. Results indicated that IBV was able to cause lesions and pass onto CEF, but not DF-1. Indeed, the virus could enter DF-1 cells and synthesize the associated structural gene but could not assemble into complete viral particles for release. Furthermore, transcriptome sequencing analysis showed significant differences in gene expression between CEF and DF-1 cells after viral infection, although the corresponding antiviral responses could be activated in both cell types. The biggest difference was in terms of the amino acid biosynthesis pathway and the cytokine receptor interaction pathway, which were significantly and specifically activated in CEF. This could actually explain why intact viruses can be assembled but not in DF-1. In addition, SLBP and P2RX7 affect the replication of IBV's structural genes to some extent. Overall, IBV can enter CEF and DF-1 cells, but the complex intracellular cytokine interactions affect the assembly and release of viral particles. The insight will be useful for the study of IBV through in vitro transmission and pathogenesis. IMPORTANCE Infectious bronchitis virus (IBV) is responsible for high morbidity and mortality as well as substantial economic losses worldwide. Transcriptome sequencing of IBV-infected chicken embryonic fibroblast and DF-1 cells revealed that the virus elicits antiviral immunity in cells after viral infection, but IBV cannot activate DF-1 cells to produce sufficient amounts of viral structures to assemble into complete virions, which may be caused by the interactions between cytokines. The study of IBV cellular adaptations is important for vaccine development and investigation of the pathogenesis of IBV.
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Affiliation(s)
- Qingcheng Yang
- Key Laboratory of Bio-Resources and Eco-Environment, Ministry of Education, College of Life Science, Sichuan University, Chengdu, China
| | - Huiling Gong
- Key Laboratory of Bio-Resources and Eco-Environment, Ministry of Education, College of Life Science, Sichuan University, Chengdu, China
| | - Song Liu
- Key Laboratory of Bio-Resources and Eco-Environment, Ministry of Education, College of Life Science, Sichuan University, Chengdu, China
| | - Siyu Huang
- Key Laboratory of Bio-Resources and Eco-Environment, Ministry of Education, College of Life Science, Sichuan University, Chengdu, China
| | - Wenjun Yan
- Key Laboratory of Bio-Resources and Eco-Environment, Ministry of Education, College of Life Science, Sichuan University, Chengdu, China
| | - Kailu Wang
- Key Laboratory of Bio-Resources and Eco-Environment, Ministry of Education, College of Life Science, Sichuan University, Chengdu, China
| | - Hao Li
- Key Laboratory of Bio-Resources and Eco-Environment, Ministry of Education, College of Life Science, Sichuan University, Chengdu, China
| | - Chang-Wei Lei
- Key Laboratory of Bio-Resources and Eco-Environment, Ministry of Education, College of Life Science, Sichuan University, Chengdu, China
| | - Hong-Ning Wang
- Key Laboratory of Bio-Resources and Eco-Environment, Ministry of Education, College of Life Science, Sichuan University, Chengdu, China
| | - Xin Yang
- Key Laboratory of Bio-Resources and Eco-Environment, Ministry of Education, College of Life Science, Sichuan University, Chengdu, China
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