An in vitro study of type I interferon and inflammatory markers induced by dsRNA and dsRNA-phytoglycogen in rainbow trout

Understanding the induction patterns for rainbow trout type I interferon and inflammatory markers is essential for the development of new antipathogenic therapeutics and vaccines as well as enhancing aquaculture productivity and biosecurity. Type I interferons (ex. ifn1) and interferon stimulated genes (ex. vig-3) as well as inflammatory markers such as interferon gamma (ifn-γ) and interleukin 1beta (il-1β) all play a crucial role in protecting rainbow trout against pathogen infection. One strategy to better understand how fish defend themselves is by studying the effects of synthetic viral dsRNA analogues such as polyinosinic:polycytidylic acid (poly IC) on the fish innate immune response. The current work utilizes a phytoglycogen-based nanoparticle (Nanodendrix; NDx) to enhance the immunostimulatory effects of poly IC in three rainbow trout cell lines derived from monocyte/macrophages (RTS11), gonads (RTG-2) and gill (RTgill-W1). Variations in innate immune responses were observed between cell lines, between poly IC and poly IC + NDx treatment groups and between transcript, protein and antiviral response levels of study. The poly IC + NDx complex demonstrated prolonged immune stimulation up to 96h post-treatment and exhibited significant inhibition of infectious pancreatic necrosis virus (IPNV) replication. These findings highlight the potential of poly IC + NDx complexes as a novel antiviral therapeutic approach for future in vitro and in vivo studies.