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.

Serological Hendra Virus Diagnostics Using an Indirect ELISA-Based DIVA Approach with Recombinant Hendra G and N Proteins

“…We have developed and evaluated a HeV DIVA ELISA assay that not only allows the detection of positive horse sera, but also discrimination between HeV-vaccinated and -infected horses. DIVA approaches are also considered crucial for an effective control of other animal diseases where vaccines are available, such as classical swine fever [43], equine influenza [44], avian influenza [45,46], foot and mouth disease [47], and Aujeszky's disease [48]. This discrimination is indispensable for an effective and economic disease control, as it allows the safe exclusion of vaccinated animals from culling schemes.…”