Abstract: Influenza (flu) pandemics have exhibited a great threat to human health throughout history. With the emergence of drug-resistant strains of influenza A virus (IAV), it is necessary to look for new agents for treatment and transmission prevention of the flu. Defensins are small (2–6 kDa) cationic peptides known for their broad-spectrum antimicrobial activity. Beta-defensins (β-defensins) are mainly produced by barrier epithelial cells and play an important role in attacking microbe invasion by epithelium. In this study, we focused on the anti-influenza A virus activity of mouse β-defensin 1 (mBD1) and β defensin-3 (mBD3) by synthesizing their fusion peptide with standard recombinant methods. The eukaryotic expression vectors pcDNA3.1(+)/mBD1-mBD3 were constructed successfully by overlap-PCR and transfected into Madin-Darby canine kidney (MDCK) cells. The MDCK cells transfected by pcDNA3.1(+)/mBD1-mBD3 were obtained by G418 screening, and the mBD1-mBD3 stable expression pattern was confirmed in MDCK cells by RT-PCR and immunofluorescence assay. The acquired stable transfected MDCK cells were infected with IAV (A/PR/8/34, H1N1, 0.1 MOI) subsequently and the virus titers in cell culture supernatants were analyzed by TCID50 72 h later. The TCID50 titer of the experimental group was clearly lower than that of the control group (p < 0.001). Furthermore, BALB/C mice were injected with liposome-encapsulated pcDNA3.1(+)/mBD1-mBD3 through muscle and then challenged with the A/PR/8/34 virus. Results showed the survival rate of 100% and lung index inhibitory rate of 32.6% in pcDNA3.1(+)/mBD1-mBD3group; the TCID50 titer of lung homogenates was clearly lower than that of the control group (p < 0.001). This study demonstrates that mBD1-mBD3 expressed by the recombinant plasmid pcDNA3.1(+)/mBD1-mBD3 could inhibit influenza A virus replication both in vitro and in vivo. These observations suggested that the recombinant mBD1-mBD3 might be developed into an agent for influenza prevention and treatment.
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Li, W.; Feng, Y.; Kuang, Y.; Zeng, W.; Yang, Y.; Li, H.; Jiang, Z.; Li, M. Construction of Eukaryotic Expression Vector with mBD1-mBD3 Fusion Genes and Exploring Its Activity against Influenza A Virus. Viruses 2014, 6, 1237-1252.
Li W, Feng Y, Kuang Y, Zeng W, Yang Y, Li H, Jiang Z, Li M. Construction of Eukaryotic Expression Vector with mBD1-mBD3 Fusion Genes and Exploring Its Activity against Influenza A Virus. Viruses. 2014; 6(3):1237-1252.
Li, Wanyi; Feng, Yan; Kuang, Yu; Zeng, Wei; Yang, Yuan; Li, Hong; Jiang, Zhonghua; Li, Mingyuan. 2014. "Construction of Eukaryotic Expression Vector with mBD1-mBD3 Fusion Genes and Exploring Its Activity against Influenza A Virus." Viruses 6, no. 3: 1237-1252.