Ke Liu, Beili Huan, Donghua Shao, Gaini Ma, Pengfei Qi, Yuming Li, Yafeng Qiu, Yuanyuan Shi, Jianchao Wei and Zhiyong Ma
Background: Porcine reproductive and respiratory syndrome (PRRS) is an economical devastating disease of swine industry worldwide, especially in China. The pathogen responsible for this disease calls porcine reproductive and respiratory syndrome virus (PRRSV), against which, we developed a specific drug from phage display screen.
Methods: We selected a peptide SPHIIRNHRLSK (P3) through phage screening technology against PPRSV polymerase. Adopting Real-time PCR and tissue culture infective dose (TCID50) assay, we assessed the antiviral activity and cytotoxicity of peptide P3. Moreover, we defined the mechanism of inhibition effect of P3 by using Biomolecular fluorescence complementation assay (BiFC). Rhodamine labelling peptide, combined with the confocal fluorescence microscopy helped us visualize the absorption kinetics of P3 in cells directly. All the experiments were conducted in MARC-145 cells.
Results: P3 shared the same structure and positive charge with the anti-bacterial peptides. We proved that P3 indeed exhibited high antiviral activity through directly binding with PRRSV polymerase and exhibited low toxicity to cells. P3m inhibited PRRSV replication in MARC-145 cells in a dose-dependent manner and could pass through the surface of the cells to directly bind with PRRSV polymerase,
which indicated the prevention and therapy effect of P3. All these results explained the specific mechanism of antiviral ability of P3.
Conclusion: All of the above facts suggested that the peptide P3 might be a potential therapeutic drug for PRRSV infection