Determination of Antiviral Activity of Isoprinosine on FMDV Serotypes O, A, and SAT2

Ibrahim, Ehab El-sayed; Mohamed, Heba; Mohamed, Safy Eldin Mahdy; Abdo, Eman Reda

doi:10.21608/scvmj.2025.396233.1206

Determination of Antiviral Activity of Isoprinosine on FMDV Serotypes O, A, and SAT2

Document Type : Original Article

Authors

¹ Department of Foot and Mouth Disease Vaccine Research, Veterinary Serum and Vaccine Research Institute (VSVRI), Agricultural Research Centre (ARC), Egypt.

² Quality control laboratory (QCL), veterinary serum and vaccine research institute

10.21608/scvmj.2025.396233.1206

Abstract

Background: One of the most contagious viral infections that affects animals with cloven hooves is Foot and Mouth Disease (FMD), which causes significant financial losses for the livestock sector. Due to the limitations of current vaccines and treatments, there is a growing need for effective antiviral agents. Isoprinosine, an immunomodulatory compound, was evaluated in this study for its virucidal activity against FMDV.
Aim: This study assessed the in vitro and in vivo antiviral efficacy of Isoprinosine against FMDV serotypes (O, A, and SAT2).
Material and Methods: FMDV serotypes O, A, and SAT2 were subjected to the present work. The experimental design included cytotoxicity assays of Isoprinosine in the BHK21 cell line, followed by investigation of its in vitro virucidal effect at various concentrations (1000, 500, 250, and 125 µg/ml). Isoprinosine in vivo assays were conducted in mice and guinea pigs against viral challenge.
Results: Toxicity assays revealed that all tested concentrations of Isoprinosine did not show any abnormal changes in the BHK21 cell line, as they were safe in mice and guinea pigs. It induced strong in vitro virucidal activity, achieving 100% virus inactivation at 1000, 500, and 250 µg/ml concentrations. At 125 µg/ml, partial inhibition was still observed, with a virus titer reduction of approximately 75–78%. In vivo, Isoprinosine provided 100% protection against FMDV at 1000, 500, and 250 µg/ml concentrations in both animal models. Even at 125 µg/ml, high protection rates (75–86.6%) were recorded, while control groups showed 100% infection and mortality.
Conclusion: Isoprinosine could be an effective antiviral agent for withstanding and controlling FMD infections. Further studies are warranted to explore its mechanism of action and application in field conditions.

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