E!12402 VASIP Intervacc AB

Important results from the project

Streptococcus suis is an important endemic pathogen of piglets, causing meningitis, arthritis, endocarditis and septicaemia with mortality rates of between 1% and 20%. Piglets are most susceptible to infection in the period immediately post-weaning leading to treatment with antibiotics and significant economic losses to the pig industry worldwide. This project aimed to develop and test the safety, immunogenicity and efficacy of a new recombinant fusion protein vaccine using a new experimental S. suis challenge system in recently-weaned piglets.

Expected long term effects

Five recombinant fusion proteins comprised of a total of 22 proteins from Streptococcus suis were produced and formulated into a prototype vaccine to target multiple virulence pathways and account for variation across the population of S. suis. Pregnant sows were vaccinated with three doses of the prototype vaccine, generating high levels of antibodies in their blood sera and colostrum. Piglets from vaccinated sows acquired similarly high antibody levels in their blood serum, and were protected significantly against challenge with S. suis at both 4 weeks and 7 weeks of age.

Approach and implementation

Intervacc has over 15 years of experience in the development of novel veterinary vaccines and had overall responsibility for the project. The Swedish University of Agricultural Sciences designed and produced the multicomponent recombinant fusion proteins utilised in this project. The S. suis challenge system developed and performed, at Moredun Scientific in the UK. Monoclonal antibodies against specific porcine IgG isotypes were developed at Moredun Scientific and the measurement of IgG responses was performed in collaboration with the Karolinska Institutet.