Differential response of RTGUTGC and RTGILL-W1 rainbow trout epithelial cell lines to viral stimulation.

Mucosal surfaces constitute the main route of entry of pathogens into the host. In fish, these mucosal tissues include, among others, the gastrointestinal tract, the gills and the skin. However, knowledge about the mechanisms of regulation of immunity in these tissues is still scarce, being essential to generate a solid base that allows the development of prevention strategies against these infectious agents. In this work, we have used the RTgutGC and RTgill-W1 epithelial-like cell lines, derived from the gastrointestinal tract and the gill of rainbow trout (Oncorhynchus mykiss), respectively, to investigate the transcriptional response of mucosal epithelial cells to a viral mimic, the dsRNA poly I:C, as well as to two important viral rainbow trout pathogens, namely viral haemorrhagic septicaemia virus (VHSV) and infectious pancreatic necrosis virus (IPNV). Additionally, we have established how the exposure to poly I:C affected the susceptibility of RTgutGC and RTgill-W1 cells to both viruses. Our results reveal important differences in the way these two cell lines respond to viral stimuli, providing interesting information on these cell lines that have emerged in the past years as useful tools to study mucosal responses in fish.