Antiviral Specificity of the Solea senegalensis Mx Protein Constitutively Expressed in CHSE-214 Cells

Abstract

Interferons play a key role in fish resistance to viral infections by inducing the expression of antiviral proteins, such as Mx. The aim of the present study was to test the antiviral activity of the Senegalese sole Mx protein (SsMx) against RNA and DNA viruses pathogenic to fish, i.e. the infectious pancreatic necrosis virus (IPNV, dsRNA), the viral haemorrhagic septicaemia virus (VHSV, ssRNA), and the European sheatfish virus (ESV, dsDNA), using a CHSE-214 cell clone expressing this antiviral protein. A strong inhibition of IPNV and VHSV replication was recorded in SsMx-expressing cells, as has been shown by the virus yield reduction and the decrease in the synthesis of the viral RNA encoding the polyprotein (for IPNV) and the nucleoprotein (for VHSV). The titres of these viruses replicating on SsMx-expressing cells were 100 times lower than those recorded on non-transfected cells. In contrast, SsMx did not inhibit ESV replication since no significant differences were observed regarding the virus yield or the major capsid protein gene transcription in transfected and non-transfected cells.

In vivo study of viral haemorrhagic septicaemia virus and infectious pancreatic necrosis virus coexistence in Senegalese sole (Solea senegalensis)

“…; Alvarez‐Torres et al . ); however, the present study shows a short‐term Mx overexpression, which could explain the low antiviral effect recorded in terms of survival rate.…”

“…Moreover, the Solea senegalensis Mx inhibitory effect on VHSV replication has been demonstrated in salmonid cells expressing this protein (Alvarez‐Torres et al . ). Therefore, our results indicate that the antiviral state against VHSV apparently conferred by the primary IPNV infection may be involved in the dramatic reduction of the mortality observed in superinfected Senegalese sole, as suggested for rainbow trout (de Kinkelin et al .…”

“…) and VHSV (Alvarez‐Torres et al . ). In addition, moderate and high Mx transcription levels have been recorded in IPNV‐ and VHSV‐infected sole, respectively (Fernandez‐Trujillo et al .…”

Ranaviruses

“…Similarly, Barramundi Mx inhibits replication of the nodavirus viral nervous necrosis virus (VNNV) and of Infectious pancreatic necrosis virus (IPNV) but fails to show antiviral effects against Taiwan grouper iridovirus (TGIV) Wu and Chi 2007 ). Likewise, Senegalese sole Mx confers antiviral effects against the IPNV and Viral hemorrhagic septicemia virus (VHSV, family Rhabdoviridae ), but not against the ranavirus European sheatfi sh virus (ESV) (Alvarez-Torres et al 2013 ). Finally, rainbow trout Mx1 is antiviral towards IPNV, Salmonid alpha virus (SAV, Togaviridae ), and infectious hematopoetic necrosis virus (IHNV, Rhabdoviridae ), but is not effective at blocking replication of EHNV (Lester et al 2012 ;Trobridge et al 1997 ).…”

Ranavirus Host Immunity and Immune Evasion

“…Interestingly, seabream possess at least three Mx proteins. One Mx isoform effectively inhibits replication of VHSV and LCDV, a second Mx molecule effectively inhibits replication of European sheatfi sh virus and LCDV, and the third is protective against VHSV (Alvarez-Torres et al 2013 ;Fernandez-Trujillo et al 2013 ). This represents the fi rst example of a teleost Mx molecule effectively inhibiting DNA virus infection.…”