Expression analysis of Mx protein and evaluation of its antiviral activity against sole aquabirnavirus in SAF-1 and TV-1 cell lines.

ABSTRACT

The transcription of Mx mRNA after poly IC induction and sole aquabirnavirus infection has been analysed in SAF-1 and TV-1 cells (derived from gilt-head seabream and turbot, respectively). Both cell lines were stimulated with 10 microg ml(-1) poly IC and Mx mRNA was analysed by a specific RT-PCR at several times post-induction. The results showed a high level of Mx expression from 12 to 120 h after induction in SAF-1 cells, whereas in TV-1 cells Mx mRNA was only detected at 12 and 24h. The treatment with different concentrations of poly IC showed that TV-1 cells are less sensitive to this inductor than the SAF-1 cell line. The antiviral activity derived from poly IC induction has been clearly demonstrated against sole aquabirnavirus on both cell lines. The inoculation of sole aquabirnavirus resulted in the Mx mRNA transcription at 48, 72, and 96 h post-infection (p.i.) in SAF-1 cells. On the contrary, inoculated TV-1 cells only showed a faint Mx mRNA band at 24 and 48 h p.i. This study has established different patterns of Mx expression in both cells under study as a consequence of the poly IC induction and sole aquabirnavirus infection, and it shows that gilt-head seabream and turbot Mx inhibit sole aquabirnavirus replication.