Generation of an avian influenza DIVA vaccine with a H3-peptide replacement located at HA2 against both highly and low pathogenic H7N9 virus

ABSTRACT

A differentiating infected from vaccinated animals (DIVA) vaccine is an ideal strategy for viral eradication in poultry. Here, according to the emerging highly pathogenic H7N9 avian influenza virus (AIV), a DIVA vaccine strain, named rGD4_HALo-mH3-TX, was successfully developed, based on a substituted 12 peptide of H3 virus located at HA2. In order to meet with the safety requirement of vaccine production, the multi-basic amino acid located at the HA cleavage site was modified. Meanwhile, six inner viral genes from a H9N2 AIV TX strainwere introduced for increasing viral production. The rGD4_HALo-mH3-TX strain displayed a similar reproductive ability with rGD4 and low pathogenicity in chickens, suggesting a good productivity and safety. In immuned chickens, rGD4_HALo-mH3-TX induced a similar antibody level with rGD4 and provided 100% clinical protection and 90% shedding protection against highly pathogenic virus challenge. rGD4_HALo-mH3-TX strain also produced a good cross-protection against low pathogenic AIV JD/17. Moreover, serological DIVA characteristics were evaluated by a successfully established competitive inhibition ELISA based on a 3G10 monoclonal antibody, and the result showed a strong reactivity with antisera of chickens vaccinated with H7 subtype strains but not rGD4_HALo-mH3-TX. Collectedly, rGD4_HALo-mH3-TX is a promising DIVA vaccine candidate against both high and low pathogenic H7N9 subtype AIV.

KEYWORDS:

• Avian influenza virus
• H7N9
• DIVA
• recombinant vaccine
• competitive inhibition ELISA

Disclosure statement

No potential conflict of interest was reported by the author(s).

Authors’ contributions

D.X.P. and T.Q. were responsible for experiment design. G.L., J.F., and Z.H.S. carried out the experiments and analyzed the results. T.Q. and G.L. wrote this manuscript. K.J.Q., Y.C.Y., Y.Y.Y., and J.S.C. provided suggestions for the experiments and helped to analyze the results. D.X.P. and X.F.L. revised the manuscript. All authors approved the final manuscript.

Data availability

All data are available from the authors upon reasonable request.

Additional information

Funding

This work was supported by the National Key Research and Development Program of China [2021YFD1800202], the Key R&D Project of Jiangsu Province [BE2018358], the Jiangsu Provincial Natural Science Fund for Excellent Young Scholars [BK20200105], the Agricultural Science and Technology Independent Innovation Fund of Jiangsu Province [CX(20)3092], the High-Level Talent Support Plan of Yangzhou University [(2018) NO.10, (2020) NO.28], Yangzhou University Interdisciplinary Research Foundation for Veterinary Medicine Discipline of Targeted Support [yzuxk202004] and a project funded by the Priority Academic Program Development of Jiangsu Higher Education [PAPD, (2018) NO. 87-169].