[In vitro antiviral activity of antisense oligonucleotides against influenza virus]

For developing of antisense oligonucleotides as potential antiviral therapeutic agents against influenza A virus, phosphorothioate oligodeoxynucleotides(PS-ODN) targeted to part to the 3' and 5' end sequences which are common to the eight RNAs of type A influenza virus were synthesized. The in vitro cytotoxicity of these PS-ODNs was assayed and then antiviral activity of these PS-ODNs was evaluated by using cultured MDCK cells infected by A/JingFang/86-1(H1N1). It was found that(1) No in vitro cytotoxicity was seen when concentration of PS-ODN was up to 50 mumol/L. (2) Oligonucleotides(IV4 #) complementary to 5' terminal conserved sequences and ODN(IV6 #, IV7 #)composed by 3'/5' terminal conserved sense sequences or antisense sequences all exhibited the most potent antiviral activity. IV4 # ODN exhibited significant antiviral activity with reduced hemegglutination titer about 50% at concentration of 1 mumol/L, and over 70% at 10 mumol/L. The antiviral activity of IV4 # was in a dose- and sequence-dependent manner. (3) IV4 # ODN showed significant antiviral activity not only against H1N1 subtype strains of influenza virus, but also against H3N2 subtype strains. (4) The multiplicity of infection(MOI) of influenza virus had effects on antiviral activity of IV4 # ODN. IV4 # ODN showed better dose-dependent antiviral activity when there was lower MOI. These results suggested the the 3'/5' terminal sequences of influenza A virus could be used as a target for designing antiviral oligonucleotides against influenza A virus.