Recombinant bluetongue virus with hemagglutinin epitopes in VP2 has potential as a labeled vaccine

Bluetongue (BT) is an arbovirus-borne disease of ruminants caused by bluetongue virus (BTV) that has the potential to have a serious economic impact. Currently available commercial vaccines include attenuated vaccines and inactivated vaccines, both of which have achieved great success in the prevention and control of BTV. However, these vaccines cannot distinguish between infected animals and immunized animals. To control outbreaks of BTV, the development of labeled vaccines is urgently needed. In this study, we used the plasmid-based reverse genetics system (RGS) of BTV to rescue four recombinant viruses in which HA (influenza hemagglutinin) tags were inserted at different sites of VP2. In vitro, the recombinant tagged viruses exhibited morphologies, plaque, and growth kinetics similar to the parental BTV-16, and expressed both VP2 and HA tag. Subsequently, the selected recombinant tagged viruses were prepared as inactivated vaccines to immunize IFNAR(-/-) mice and sheep, and serological detection results of anti-HA antibody provided discriminative detection. In summary, we used plasmid-based RGS to rescue BTV recombinant viruses with HA tags inserted into VP2, and detected several sites on VP2 that can accommodate HA tags. Some of the recombinant tagged viruses have potential to be developed into distinctive inactivated vaccines.