Two major viral diseases of poultry that are endemic worldwide are infectious bursal disease virus (IBDV) and infectious bronchitis virus (IBV). Currently, vaccines are administered against each disease separately, and IBV vaccines do not adequately cross-protect against diverse field strains. Multivalent vaccines that protect against multiple viruses are more cost-effective, and vaccines that induce more broadly cross-protective immune responses against diverse strains of viruses are preferable.
This study aimed to engineer a recombinant IBDV as a vector expressing previously characterised, broadly neutralising B- and T-cell epitopes from IBV that could elicit protective humoral and cellular immune responses that protect against both viral infections. IBDV strains D78, currently used for IBDV vaccination, and PBG98, the best lab-adapted strain, were used throughout the project. A conserved B-cell epitope from IBV was inserted into the VP5 region of the D78 strain of IBDV, while the antigenic domain of the M41 spike protein from IBV was inserted into the PBG98 as proof of principle. Initial results indicate that the wild-type D78 strain reverse genetic system was successfully produced for the first time, and both chimeric PBG98 and D78 with IBV epitopes were produced and maintained till passage 3.
This research provides a basis for the development of a multivalent vaccine using IBDV as a platform.
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