Construction of a Toolbox of enabling technology for coronavirus vaccine strategies
Coronaviruses (CoVs) are important pathogens for humans and animals. Feline CoVs can infect cats which generally leads to a relatively mild disease. In some cases, the Feline CoV infections can develop into the fatal disease Feline Infectious Peritonitis (FIP) which is caused by the Feline Infectious Peritonitis Virus (FIPV). The aim of this project is the development of a vaccine against FIPV, based on live attenuated versions of this virus. The virology division of the Faculty of Veterinary Medicine of Utrecht University (‘UU’) has expertise and developed unique tools to study CoVs. The scientists of UU collaborate with the veterinary pharmaceutical company Merial, that was acquired by Boehringer Ingelheim in 2017, with expertise in the development, production, and commercialisation of veterinary vaccines.
Development and characterisation of live attenuated FIPV candidates is not only important for developing a FIPV vaccine, but it will also provide important scientific information on how to best attenuate other CoVs. Overall, animal CoVs are well known for their ability to cause zoonotic infections in humans by crossing the species barrier. Such zoonotic events can have dramatic clinical and socio-economic implications, as exemplified by the outbreaks with SARS-CoV and MERS-CoV, both of which emerged from animals, and both of which have resulted in many deaths and social distress.
In this project, two different (genetic) approaches were followed to attenuate the FIPV vaccine virus. Both approaches resulted in FIPV mutants that were extensively characterized in vitro.
Both types of mutants were grown to high titers and safety experiments in cats were performed. Both mutants were severely attenuated and showed relatively few clinical signs. Cats infected with one of the mutants showed the least signs of clinical disease, so Boehringer Ingelheim will proceed with this candidate to vaccination-challenge experiments in cats in the coming months.