Cell-Type-Specific Molecular Responses to Avian Reovirus Inoculation In Vitro

Avian reovirus (ARV) is an important pathogen of poultry, yet the molecular responses to ARV across cell-types remain unknown. The present study explores the differential transcriptomic responses to ARV S1133 infection in three cell types, i.e. chicken embryo kidney (CEK), chicken embryo liver (CELi), and macrophage-derived cells (HD11) at 6, 12 and 24 hours post-inoculation (hpi). CELi cells exhibited the highest viral replication rates at all timepoints, with maximal titer observed at 24 hpi, whereas HD11 cells showed limited viral replication but extensive host transcriptional activity. Differential gene expression analysis revealed that HD11 cells, despite the lower viral load, presented the most pronounced transcriptional changes. CEK cells demonstrated a unique activation of immune-related pathways, specifically those related to lymphocyte chemotaxis and type II interferon response. CELi cells showed upregulation of expression of genes involved in defense against viruses. Protein-protein interaction (PPI) analysis identified key antiviral genes, including IFI6, OASL, RSAD2, SAMD9L, and MX1, as central nodes. In CELi, significant alternative splicing events were observed in transcripts of several genes, including those implicated in immunity. Taken together, results indicate that inoculation of ARV entailed cell-type and time-dependent viral replication and triggered transcriptional activity linked with unique but functionally interconnected pathways.