Transcriptomic analysis of Crandell-Rees feline kidney cell infections with field and vaccine feline calicivirus strains

Feline upper respiratory tract disease (URTD) is a significant health concern in crowded environments, such as catteries and shelters. Feline calicivirus (FCV), which is endemic in domestic cats, is a major contributor to URTD and can cause a range of diseases that vary in severity. Unlike many other caliciviruses, including human caliciviruses and noroviruses, FCV replicates efficiently in cell culture and is a well-established model for studying calicivirus-host cell interactions. In this study, RNA-sequencing was used to characterise host and viral transcription profiles in Crandell-Rees feline kidney (CRFK) cells infected with either the attenuated F9 vaccine strain or a virulent field strain associated with virulent systemic FCV (VS-FCV) disease. At six hours post-infection, both strains induced the upregulation of inflammatory and stress response pathways, while genes involved in metabolism, cell signalling, and extracellular matrix maintenance were downregulated. Between field and vaccine strains, pathways related to membrane signalling and cytoskeletal organisation were uniquely altered in the field strain, while the F9 vaccine strain distinctly altered chromatin organisation, cytokine signalling and mitochondrial metabolism. These findings demonstrate the virulence of FCV strains differentially influences host gene expression in CRFK cells, which may inform host-pathogen interactions that contribute to FCV pathogenesis and variations in disease outcomes.