New Frontiers in FIP: A Cat and Mouse Game of Vaccination

Developing an effective vaccine against feline infectious peritonitis (FIP) has proven exquisitely challenging. Despite over 60 years of research on this deadly disease, access to a vaccine which is safe, effective, and can be used in the face of chronic infection with feline coronavirus remains out of reach. The highly complex pathogenesis of disease along with a limited understanding of what constitutes a protective immune response to clear chronic infection prior to the onset of FIP are in large part why this tool has been so difficult to develop. This session will focus on the preclinical development of an mRNA vaccine for feline coronavirus, with emphasis on the strategy behind what makes this platform uniquely poised to address the challenges presented by FIP vaccine development. The COVID-19 pandemic has substantially advanced vaccine platform development, with increased ease of availability and resources for novel types of vaccines. However, there has been minimal translation to veterinary medicine. This session describes application of the novel mRNA vaccine technology to FIP. Lessons learned from the pandemic as they pertain to developing a vaccine for FIP will be discussed as well, with details on the ways in which complex immune responses to feline coronavirus differ from that of SARS-CoV-2 in humans. Data from studies assaying antigen production in transfected feline cells in vitro, as well as durability of mRNA, will be presented. Studies in vaccinated mice will be detailed as well, which provide proof of concept for this novel vaccine and its ability to elicit appropriate immune responses. This session will share historical challenges and novel ways to overcome them with the ultimate goal of developing a vaccine for clinical use to prevent FIP.