In vitro and in vivo protection against the highly pathogenic H5N1 influenza virus by an antisense phosphorothioate oligonucleotide.
BACKGROUND
Current vaccination strategies and antiviral drugs only provide limited protection against influenza virus infection. In this study, we investigated the use of a novel antisense oligonucleotide (named IV-AS), which is specific for the 5'-terminal conserved sequence found in all eight viral RNA segments of influenza A virus.


METHODS
The activity of IV-AS was monitored both in vitro, in Madin-Darby canine kidney (MDCK) cells, and in vivo using a mouse model. IV-AS was given intranasally to H5N1-infected mice once daily for 6 days starting 6 h after infection. A three-base mismatch of IV-AS was used as a control.


RESULTS
IV-AS inhibited influenza virus A induced cytopathic effects in MDCK cells with the 50% effective concentration (EC50) ranging from 2.2 to 4.4 microM. IV-AS was effective against H5N1 virus in preventing death, lessening weight reduction, inhibiting lung consolidation and reducing lung virus titres. Dosages of 40 and 60 mg/kg/day provided 40% and 60% survival rates and prolonged mean survival days in comparison with the infected control group (P<0.05). The lung index in mice treated with IV-AS, at a dose of 20, 40 or 60 mg/kg/day, had been inhibited on day 4 or 6 (P<0.05 or P<0.01); virus titres in lung had declined to 2.42, 1.51 and 1.54 log10 TCID50/g of lung, respectively, whereas the yields in the infected control mice were 6.00 log10 TCID50/g of lung.


CONCLUSIONS
Our results suggest that the 5'-terminal conserved region of influenza A virus RNA segments can be targeted using antisense technology; therefore, IV-AS is a potential drug for prophylaxis and control of influenza virus infections.
Duan
Ming
M
Beijing Institute of Radiation Medicine, Beijing 100850, PR China.
Zhou
Zhe
Z
Lin
Ru-Xian
RX
Yang
Jing
J
Xia
Xian-Zhu
XZ
Wang
Sheng-Qi
SQ
D000818:Animals; D002460:Cell Line; D003588:Cytopathogenic Effect, Viral; D004285:Dogs; D004305:Dose-Response Relationship, Drug; D053124:Influenza A Virus, H5N1 Subtype / Q000276:immunology*; D008168:Lung / Q000473:pathology / Q000821:virology; D051379:Mice; D008807:Mice, Inbred BALB C; D016376:Oligonucleotides, Antisense / Q000009:adverse effects / Q000276:immunology*; D009976:Orthomyxoviridae Infections / Q000276:immunology* / Q000821:virology; D054735:Phosphorothioate Oligonucleotides / Q000009:adverse effects / Q000276:immunology*; D013047:Specific Pathogen-Free Organisms; D013997:Time Factors
D016376:Oligonucleotides, Antisense; D054735:Phosphorothioate Oligonucleotides