JAC Advance Access published online on June 19, 2008
Journal of Antimicrobial Chemotherapy, doi:10.1093/jac/dkn221
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Original research |
Treatment of AG129 mice with antisense morpholino oligomers increases survival time following challenge with dengue 2 virus
1 AVI BioPharma Inc., 4575 SW Research Way, Corvallis, OR 97333, USA 2 Division of Vector-Borne Infectious Diseases, Centers for Disease Control and Prevention, Public Health Service, U.S. Department of Health and Human Services, Fort Collins, CO, USA
Received 18 March 2008; returned 2 May 2008; revised 7 May 2008; accepted 9 May 2008
* Corresponding author. Present address. Department of Microbiology, Oregon State University, Corvallis, OR, USA. Tel: +1-541-737-4441; Fax: +1-541-737-0496; E-mail: dave.stein{at}comcast.net
Objectives: To determine the antiviral activity of phosphorodiamidate morpholino oligomers (PMO) and peptide-conjugated PMO (PPMO) in AG129 mice infected with dengue 2 virus (DENV-2).
Methods: Antisense PMO and PPMO were designed against the 5' terminal region (5'SL) or the 3'-cyclization sequence region (3'CS) of DENV genomic RNA and administered to AG129 mice before and/or after infection with DENV-2. In addition, cell culture evaluations designed to determine optimum PPMO length, and pharmacokinetic and toxicity analysis of PPMO were also carried out.
Results: Mock-treated AG129 mice lived for 9–17 days following intraperitoneal (ip) infection with 104–106 pfu of DENV-2 (strain New Guinea C). Intraperitoneal administration of 5'SL or 3'CS PPMO before and after DENV infection produced an increase in the average survival time of up to 8 days. Animals receiving only post-infection PPMO treatment did not benefit significantly. Cell culture studies showed that PPMO of 22–24 bases long produced substantially higher DENV titre reductions than did PPMO that were either shorter or longer. Pharmacokinetic and toxicology analysis with non-infected animals showed that nine consecutive once-daily ip treatments of 10 mg/kg PPMO resulted in high concentrations of PPMO in the liver and caused little impact on overall health.
Conclusions: The data indicate that PPMO had considerable antiviral efficacy against DENV-2 in the AG129 mouse model and that PPMO treatment early in the course of an infection was critical to extending the survival times of DENV-2-infected mice in the AG129 model system.
Key Words: flavivirus , antiviral , PMO , PPMO , antisense , dengue virus , morpholino oligomers
Present address. SIGA Technologies Inc., Corvallis, OR, USA.