A recombinant CHSE-214 cell line expressing an Mx1 promoter–reporter system responds to both interferon type I and type II from salmonids and represents a versatile tool to study the IFN-system in teleost fish

A transgenic cell line for the detection of salmon interferons (IFNs) has been established. It is based on a CHSE-214 cell line containing a reporter construct expressing firefly luciferase under the control of the rainbow trout promoter for the IFN-induced Mx1 gene. This cell line, named CHSE-Mx10, showed IFN-induced luciferase expression after more than 80 passages, confirming the stability of this cell line.Interestingly, the Mx promoter was shown to respond to both salmon IFN-α/β and trout IFN-γ in a dose-dependent manner, while there was no response to TNF-α and IL-1β. IFN-α/β activity could be measured at a range of 9–150 U/ml, and IFN-γ showed activity between 10 and 100 ng/ml. The reproducibility of both responses was good. The CHSE-Mx10 reporter system constitutes a versatile tool to study the induction and regulation of IFN signaling in teleost fish. A preliminary study presented herein suggests that both infectious pancreas necrosis virus (IPNV) and salmon pancreas disease virus (SPDV) may block activation of the Mx promoter in CHSE-Mx10 stimulated with IFN-α/β.