The Pirbright Institute has announced it is to undertake two projects with ECO Animal Health Group (ECO) to develop vaccine candidates for porcine respiratory and reproductive syndrome virus (PRRSV).
Collectively, the two PRRSV species (type-1 and type-2) are responsible for one of the most economically damaging diseases to the global pig industry, costing European pig farmers an estimated €1.5 billion a year and those in the US approximately $600 million.
The first project is a collaboration between Pirbright Institute, the Vaccine Group (TVG), a spin out from the University of Plymouth developing vaccines based on benign forms of herpesviruses, and ECO Animal Health Group, which researches, develops and commercialises products for livestock.
The 18-month development project, supported and funded by ECO, Pirbright will test two vaccine candidates that use TVG’s vaccine technology to assess their effectiveness at tackling PRRSV in pigs.
The vaccines are created by using the technology to insert non-infectious conserved PRRSV genes supplied by Pirbright into a benign herpesvirus, which then stimulates the immune system when delivered into animals. Vaccines that use herpesviruses as their base have been shown to provoke particularly strong reactions from T cells, which are a vital part of the antiviral response.
Herpesviruses are found in all animals, including humans. TVG and its international partners have so far been backed by more than £9 million in grant funding from the US, UK and Chinese governments and has already announced strong progress this year in developing vaccine candidates using the technique to tackle COVID-19, initially for use in animals.
Its vaccines for bovine tuberculosis and African swine fever virus are ready to enter animal trials once testing facilities become available, while other projects underway include developing a vaccine against Streptococcus suis, a disease in pigs which can be fatal in humans.
Professor Simon Graham, group leader of PRRS immunology at The Pirbright Institute said: “This is an exciting project that takes a novel approach to addressing the urgent requirement for improved vaccines to combat the global spread of PRRSV.”
TVG founder and chief scientific officer, Associate Professor Dr Michael Jarvis said: “As PRRSV is a member of the Nidovirus group of viruses, a group that also contains SARS-CoV-2, what we learn from development of a PRRSV vaccine may also help inform our development of a vaccine against SARS-CoV-2.”
Dr Hafid Benchaoui, head of global R&D at ECO said the collaboration ‘leverages the deep scientific expertise of Pirbright and The Vaccine Group’s novel herpesvirus vector technology in an exciting new approach to PRRSV vaccination’.
Killed vaccine
The second project is a joint collaboration between Pirbright and ECO, which will see Pirbright develop a significantly improved killed vaccine over 18 months. The team will generate modified PRRSV strains and then inactivate them to create vaccine candidates. The strain modifications aim to prevent inappropriate antibody responses and enhance those that are thought to provide immunity against multiple strains of PRRSV.
This killed vaccine would offer an attractive alternative to the current generation of live vaccines, which are only partially effective against different strains and suffer from safety constraints owing to the potential for the live vaccine virus to revert back to an infectious form.
Professor Simon said: “Creating a killed vaccine that can prevent the spread of multiple strains would provide flexibility in tackling outbreaks as well as an improved safety profile, both vital for effective control.”
Dr Benchaoui added: “This novel concept will provide better protection of pigs against PRRSV than current vaccines and will be safer by eliminating the significant risk of recombination in the field.”