IPNV is a salmonid birnavirus that possesses the ability to establish asymptomatic persistent infections in
a number of valuable fish species. The presence of IPNV may interfere with subsequent infection by other
viruses. In the present study we show that an IPNV-carrier cell line (EPCIPNV) can induce an antiviral state
in fresh EPC by co-cultivating both cell types in three different ways: a “droplet” culture system, a plastic
chamber setup, and a transmembrane (Transwell®) system. All three cell co-culture methods were proven
useful to study donor/target cell interaction. Naïve EPC cells grown in contact with EPCIPNV cells develop
resistance to VHSV superinfection. The transmembrane system seems best suited to examine gene
expression in donor and target cells separately. Our findings point to the conclusion that one or more
soluble factors produced by the IPNV carrier culture induce the innate immune response within the
target cells. This antiviral response is associated to the up-regulation of interferon (ifn) and mx gene
expression in target EPC cells. To our knowledge this is the first article describing co-culture systems to
study the interplay between virus-carrier cells and naive cells in fish.
© 2016 The Author(s). Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND