Identification of diverse defense mechanisms in trout red blood

It has been described that fish nucleated red blood cells (RBCs) Background: generate a wide variety of immune-related gene transcripts when viruses highly replicate inside them and are their main target cell. The immune response and mechanisms of fish RBCs against viruses targeting other cells or tissues has not yet been explored and is the objective of our study. Trout RBCs were obtained from peripheral blood, ficoll purified and Methods: exposed to (VHSV). Immune response Viral Haemorrhagic Septicaemia virus was evaluated by means of RT-qPCR, flow cytometry, immunofluorescence and isobaric tag for relative and absolute quantification (iTRAQ) protein profiling VHSV N gene transcripts incremented early postexposure and were Results: drastically decreased after 6 hours postexposure (hpe). The expression of the type I interferon ( ) gene was significantly downregulated at early ifn1 postexposure (3 hpe), together with a gradual downregulation of interferon-inducible and genes until 72 hpe. Type I IFN protein was mx pkr downregulated and interferon-inducible Mx protein was maintained at basal levels. Co-culture assays of RBCs with TSS (stromal cell line from spleen) revealed the IFN crosstalk between both cell types. On the other hand, anti-microbial peptide β-defensin 1 and neutrophil chemotactic factor interleukin 8 were slightly upregulated in VHSV-exposed RBCs Isobaric tag for relative and absolute quantification (iTRAQ) revealed that VHSV exposure can induce a global protein downregulation in trout RBCs, mainly related to RNA stability and proteasome pathways. The antioxidant/antiviral response is also suggested to be involved in the response of trout RBCs to VHSV. A variety of mechanisms are proposed to be implicated in the Conclusions: antiviral response of trout RBCs against VHSV halted infection. Ongoing research is focused on understanding the mechanisms in detail. To our knowledge, this is the first report that implicates fish RBCs in the antiviral 1 1 1 2