A DIVA system based on the detection of antibodies to non-structural protein 3 (NS3) of Bluetongue virus

Sílvia C. Barros , Benedita Cruz , Tiago M. Luís , Fernanda Ramos , Teresa Fagulha , Margarida Duarte , Margarida Henriques , Miguel Fevereiro

Vaccination programs for the control of bluetongue (BT) in ruminants have limitations due to difficulties in differentiating between vaccinated and virus infected animals (DIVA). To overcome this problem a DIVA test that looks at a differential immune response to bluetongue virus (BTV) non-structural protein 3 (NS3) was developed. The NS3 encoding gene of strain BTV4/22045/PT04 was inserted into expression vector pET-28a and expressed in strain JM109. Recombinant NS3 protein was used as an antigen in an indirect ELISA (NS3-ELISA) to measure the serologic response to NS3 protein in cattle and sheep. Following a cattle vaccination/challenge experiment with a bivalent inactivated BTV 2-4 vaccine, NS3 antibodies were detected at approximately 15 days post-infection in control unvaccinated animal, while vaccinated animals did not develop detectable NS3 antibodies and, with exception of one, remained negative even after virus challenge. The inactivated vaccine induced antibodies against the major core structural protein (VP7) of BTV as well as neutralizing antibodies in all animals.

Mots clés: Bluetongue virus; Non-structural proteins; NS3; ELISA; DIVA

Sílvia C. Barros, Benedita Cruz, Tiago M. Luís, Fernanda Ramos, Teresa Fagulha, et al.. A DIVA system based on the detection of antibodies to non-structural protein 3 (NS3) of Bluetongue virus. Veterinary Microbiology, 2009, 137 (3-4), pp.252. ⟨10.1016/j.vetmic.2009.01.033⟩. ⟨hal-00485540⟩