Two mutations on S2 subunit were critical for Vero cell tropism expansion of infectious bronchitis virus HV80.
Vet Microbiol
; 294: 110134, 2024 Jul.
Article
en En
| MEDLINE
| ID: mdl-38820725
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.
Palabras clave
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Virus de la Bronquitis Infecciosa
/
Tropismo Viral
/
Mutación
Límite:
Animals
Idioma:
En
Revista:
Vet Microbiol
Año:
2024
Tipo del documento:
Article