ABSTRACT
BACKGROUND: T helper 2 (Th2) lymphocytes and associated interleukin (IL) 4 and IL-13 play crucial roles in asthma pathogenesis. In this study, we explored an adeno-associated virus 5 (AAV5) based gene therapy by delivering truncated IL-4 protein to antagonize IL-4 receptor α chain and interrupt asthmatic signal pathway. RESULTS: A recombinant adeno-associated virus 5 (AAV5) vector harboring a truncated mouse IL-4 gene (AAV5-mIL-4ΔC22) was prepared. Western blotting showed that the IL-4 mutant protein lacking the C-terminal 22 amino acids was expressed well in AAV5-mIL-4ΔC22 infected 16HBE and BEAS-2B cells. AAV5-drivn green fluorescent protein (AAV5-GFP) served as a control. The biodistribution of vector DNA after AAV5 vector aerosol inhalation was examined by PCR and the result showed that foreign DNA was detectable in the lungs but not in other organs including gonads. The aerosol inhalation-mediated delivery of AAV5-expressed antagonistic IL-4 mutant protein improved the lung function of ovalbumin-induced asthma mice. CONCLUSIONS: The inhalation of aerosolized AAV5-mIL-4ΔC22 significantly improved the lung function and modulated the immune cell infiltration and associated cytokine expression in the bronchoalveolar lavage fluid (BALF) of ovalbumin-induced asthma mice.
