Poly I:C inhibits the expression of channel catfish virus immediate-early gene ORF 1 at early times after infection

Channel catfish virus (CCV) is a herpesvirus that infects channel catfish fry and fingerlings. Previous research has demonstrated that Type I interferons inhibit the expression of immediate-early (IE) genes of some mammalian herpesviruses. However, CCV is distantly related to the mammalian herpesviruses and Type I interferons from higher vertebrates exhibit only 20% similarity to fish interferons. In this work we demonstrate that treatment of channel catfish ovary (CCO) cells, a fibroblast-like cell line, with poly I:C, a known inducer of Type I interferons, results in inhibition of expression of the CCV IE gene ORF 1. Thus, although the genes involved have diverged, the mechanism appears to be conserved. If this paradigm holds true for other CCV IE-Type I interferon interactions, it could have important implications for the impact of CCV on the host immune system.