[Airway beta-defensin-2 gene transfer enhances the bacterial clearing of rat lung]

beta-defensins possess a broad spectrum of antimicrobial activity. In this study its in vivo antibacterial effect was evaluated by using gene transfer. Rat beta-defensin-2 (rBD2) recombinant pBK-CMV-rBD2 and pCD-NA-3, 1-Myc-His(+)-rBD2 were constructed. Then, by use of liposome agent, the recombinants were delivered into rat airway via tracheal injection. The rBD-2 mRNA expression was detected in the trachea by RT-PCR and its protein expression was determined in the lungs by the tag His immunostaining, 24 hours after inoculation via trachea, the count of P. areuginosa in the lung of rat transfected with pBK-CMV-rBD2 markedly decreased, compared with the control (n = 8, P = 0.003). The data presented in this study provide evidence that airway beta-defensin-2-gene transfer can protect the rat against bacterial infection in vivo, suggesting the beta-defensins as part of the innate host defense system can be of potential applicability.