MX1 and infection: As parts of the antiviral responses, the mx and rsad2 genes in the TiB cells in our study were significantly upregulated in response to TiLV infection at 24 hpi, as has previously been described in various organs, such as the liver, spleen, gills and intestines, following TiLV infection in tilapia [14,45,46,47] and the infection of different fish species by other viruses [48].