Construction of recombinant LSDV fluorescent virus for high-throughput screening of antiviral drugs

Lumpy skin disease virus (LSDV) infection is a major socio-economic issue that can cause serious threat to the global cattle farming industry. Here, a recombinant virus LSDV-ΔTK/EGFP of expressing EGFP was constructed using a homologous recombination system and applied to high-throughput screening of antiviral drugs. LSDV-ΔTK/EGFP can replicate in various kidney cell lines to consistent with wild-type LSDV. At the same time, the cytopathic effects, virus particle morphology, and growth performance caused by LSDV-ΔTK/EGFP are consistent with those of wild LSDV. High-throughput screening found that emodin (for LSDV-ΔTK/EGFP, IC50 = 10.86 µM), aloe emodin (for LSDV-ΔTK/EGFP, IC50 = 10.13 µM), theaflavin (for LSDV-ΔTK/EGFP, IC50 = 10.05 µM), 4-ethylphenol (for LSDV-ΔTK/EGFP, IC50 = 32.17 µM), tulipalin (for LSDV-ΔTK/EGFP, IC50 = 28.58 µM) and anemoside B4 (for LSDV-ΔTK/EGFP, IC50 = 845.65 µM) inhibited LSDV replication. Theaflavin strong inhibitory effect on LSDV was identified from 100 antiviral drugs in vitro. In addition, the addition time measurement shown that theaflavins play a role in the entry of LSDV into cells and subsequent viral replication stages. The development of this recombinant virus contributes to the development of LSDV antiviral drugs and the subsequent study of virus replication and mechanism of action.