The aim of the project is to develop a safe, protective and DIVA (enables Differentiation of Infected from Vaccinated Animals) compatible vaccine against brucellosis. This disease is caused by the bacteria Brucella and it is one of the world’s most common animal to human transmitted diseases. It causes considerable livestock losses in many of the most deprived areas of the world and perpetuates poverty. Some vaccines already exist for ruminants but these have numerous flaws, vaccination causes disease in a significant number of animals (which can result in abortions in livestock), accidental human exposure causes disease, and they generate an immune response that cannot be distinguished from that generated by infection. This makes running effective disease control and eradication programmes extremely challenging confounding antibodies in diagnostic tests. There is no recognised vaccine to protect humans or swine against this disease. The proposed vaccine is targeted for use in ruminants but may also be effective in humans, swine and other hosts. This vaccine candidate has several novel attributes: the O-polysaccharide (OPS) will be conjugated to a protein from the target pathogen; the OPS itself will be derived from a less hazardous organism than Brucella so that it may be grown in less stringent and expensive conditions (although the organisms are different, the OPS is virtually identical), and the OPS will be modified to enable DIVA compatibility when applied with synthetic oligosaccharide serodiagnostic antigens.
The aims of the project have been met:
- a candidate Brucella vaccine that incorporates the DIVA technology into a product that combines the induction of anti-Brucella OPS antibodies with a cell mediated immune response and can be produced without the need of high containment (BSL3) facilities has been produced
- sufficient material to enable proof of concept in-vivo studies has been produced
- methods suitable for commercial scale up of production have been developed.