Effects of viral hemorrhagic septicemia virus (VHSV) on the rainbow trout (Oncorhynchus mykiss) monocyte cell line RTS-11

The effect of viral hemorrhagic septicemia virus (VHSV) was studied on the established rainbow trout (Oncorhynchus mykiss) monocyte/macrophage-like cell line RTS11. The virus was not able to complete its replication cycle as infectious viral particles were not released from the cells. However, in RTS11, the virus was capable of producing mRNA from at least its N and G genes. At the protein level, only N protein was detected 2 days post-infection, whereas a faint band corresponding to the G protein was also observed after 5 days post-infection. These results suggest an interruption of viral protein translation at some point. The expression of N mRNA was significantly inhibited in cells pre-treated with Poly IC, but not affected by 2-aminopurine (2-AP), an inhibitor of the dsRNA-dependent protein kinase (PKR), thus indicating that PKR has no effect on mRNA expression directly. However, when cells were preincubated with Poly IC in the presence of 2-AP, the levels of N mRNA were restored suggesting that Poly IC can limit viral transcription through an antiviral mechanism dependent of PKR. The effect of VHSV on the expression of transcripts for different immune genes was determined, but significant induction was found only for genes related to the type I interferon (IFN) response, such as IFN-1 and -2 and the three Mx isoforms. Heat-inactivated virus failed to induce IFN-1 and -2, suggesting that early events in the VHSV life cycle were necessary for the type I IFN response. Poly IC alone also induced transcripts for the antiviral Mx proteins. Prior exposure of RTS11 to VHSV did not prevent Poly IC from inducing transcripts for Mx1, Mx2 and Mx3. Perhaps the failure of VHSV to disable antiviral mechanisms in RTS11 accounts for the aborted infections. © 2007 Elsevier Ltd. All rights reserved.

Bibliographic Details

Main Authors:	Tafalla Piñeiro, Carolina, Sanchez, E., Lorenzen, N., DeWitte-Orr, S. J., Bols, N. C.
Format:	artículo biblioteca
Language:	English
Published:	Elsevier 2008
Subjects:	Viral hemorrhagic septicemia virus (VHSV), Rainbow trout, Macrophages, Antiviral mechanisms, RTS11, Mx, PKR,
Online Access:	http://hdl.handle.net/20.500.12792/5506 http://hdl.handle.net/10261/292990
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