This study aimed to explore the enhanced immunogenicity of the Newcastle disease virus(NDV)La Sota strain in ducks through a dual-targeting fusion protein,providing valuable insights for improving NDV immune prevention and control capabilities.The genes encoding Griffithsin(GRFT)that specifically binds to the surface glycoprotein of enve-loped viruses and nanoantibody molecules(VHH)targeting avian dendritic cells were co-expressed in tandem using the Escherichia coli system and purified via a His-tag.The binding capacity of the GRFT-VHH fusion protein to the La Sota vi-rus was quantitatively assessed using a limited dilution method.Vaccines were prepared with La Sota virus saturated with the fusion protein and administered to groups of specific pathogen free(SPF)ducklings.After immunization,the hemagglutination inhibition(HI)anti-body titer and levels of cytokines IL-4 and IFN-γ were e-valuated.Results indicated that the constructed recombinant E.coli efficiently expressed the fusion protein.The concentra-tions of GRFT-VHH54 and GRFT-VHH74 purified by Ni column were 230 μg/mL and 1 350 μg/mL,respectively.Only 100 ng of the fusion protein was required to fully bind 1×108 median infective dose(EID50)virus.The HI antibody titer in the NDV+GRFT-VHH54 group reached more than 7 log22,and the levels of IL-4 and IFN-γ in serum were 80.0 pg/mL and 8.8 pg/mL respectively at 21 d post-immunization,which were significantly higher than those in the NDV group(P<0.05).The dual-targeting fusion protein GRFT-VHH54 can enhance the immunogenicity of the NDV La Sota strain in ducks,and can be used as an immunopotentiator for further development and application.
维普
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