Induction of secretion of interleukinª²8 from lung epithelial cells by trypsin

    WANG Haiª²Yan, HE Shaoª²Heng

    Allergy and Inflammation Research Institute, Medical College Shantou University, Shantou 515031, China

    ¡¾Abstract¡¿ AIM: To investigate the actions of trypsin on the secretion of interleukinª²8 (ILª²8) from human lung epithelial cells. METHODS: A549 cells were cultured in a 12ª²well culture plate. The challenge was performed by adding various concentrations of trypsin or trypsin inhibitor into each well, respectively. After 2 h, 8 h or 16 h, the reactions were terminated by removing the supernatant from each well. A sandwich ELISA was used to determine the levels of ILª²8 in supernatants. RESULTS: Following 16 h incubation, trypsin induced the secretion of ILª²8 in a concentration dependent manner. As low as 1 ¦Ìg/L trypsin was able to induce ILª²8 release from epithelial cells and the maximum of accumulated release of ILª²8 was observed with 3 ¦Ìg/L trypsin, which was 5ª²fold more than the baseline release. However, when trypsin concentration increased over 3 ¦Ìg/L, the extent of increased secretion of ILª²8 decreased. Soybean trypsin inhibitor (SBTI) and ¦Á1ª²antitrypsin (¦Á1ª²AT) inhibited trypsin induced secretion of ILª²8. The time course showed that the actions of trypsin initiated at 2 h and reached their peak at 16 h. CONCLUSION: Trypsin is a potent secretogogue of ILª²8 release from cultured human lung epithelial cells, indicating that it is likely to be involved in the pathophysiological process of airway inflammation. ......