Co-infection with M. cerebralis (Tb+) triggered a robust transcriptional response in rainbow trout, leading to the upregulation of 2375 genes, including interferon induced protein 44-like (IFI44L), interferon induced protein 44 (IFI44), radical S-adenosyl methionine domain containing 2 (RSAD2), ISG15 ubiquitin-like modifier (ISG15), and receptor transporter protein 5 (Putative) (RTP5). The gene discussed is IFI44L; the disease is coinfection.