Foot-and-mouth disease (FMD) is a highly contagious disease of livestock caused by a highly variable RNA virus (FMDV) that has seven serotypes and more than sixty subtypes. Both prophylactic and post-infection means of controlling the disease outbreak, including universally applicable vaccines and emergency response measures such as therapeutic treatments, are on high demand. In this study, we analyzed the long-term exposure outcome to a previously identified inhibitor of 3D polymerase (FMDV 3Dpol) for controlling FMDV infection and for the selection of resistance mutants. The results showed that no escape mutant viruses were isolated from FMDV A24 Cruzeiro infections in cell culture treated with gradually increasing concentrations of the antiviral compound 5D9 (4-chloro-N'-thieno, [2,3-d]pyrimidin-4-ylbenzenesulfonohydrazide) over ten passages. Biochemical and plaque assays revealed that when 5D9 was used at concentrations within a non-toxic range in cells, it drove the virus to undetectable levels at passage eight to ten. This is in contrast with observations made on parallel control (untreated) passages exhibiting fully viable and stable virus progenies. Collectively, the results demonstrated that under the experimental conditions, treatment with 5D9 does not confer a resistant phenotype and the virus is unable to evade the antiviral effect of the inhibitor. Further efforts using quantitative structure-property relationship (QSPR) based modifications of the 5D9 compound may result in the successful development of an effective in vivo antiviral drug targeting FMDV.
Bibliographical noteFunding Information:
This research was supported in part by CRIS project no. 1940-32000-057-00D, Agricultural Research Service (ARS), U.S. Department of Agriculture (Elizabeth Rieder) and USDA-ARS-58-1940-5-519. USDA-ARS-58-1940-8-868; NIH grants AI076119, AI099284, and AI100890 (Stefan G. Sarafianos). Dr D. Rai is the recipient of a fellowship by the Plum Island Animal Disease Research Participation Program administered by the Oak Ridge Institute for Science and Education through an interagency agreement between the U.S. Department of Energy and the U.S. Department of Agriculture. We thank A. Clavijo ( National Centre for Foreign Animal Disease , 1015 Arlington Street, Winnipeg, Manitoba, Canada) for the gift of monoclonal antibodies targeting the FMDV 3D polymerase protein.
- 3D polymerase inhibitor
- 5D9 compound
- FMDV therapeutic treatment
- Foot-and-mouth disease virus (FMDV)