HOU Yiª²Feng, ZHOU Yanª²Chun, ZHENG Xiaoª²Xuan, WANG Haiª²Yan, FU Yiª²Ling, FANG Zeª²Man, HE Shaoª²Heng

    Allergy and Inflammation Research Institute, Medical College, Shantou University, Shantou 515041, China

    ¡¾Abstract¡¿ AIM: To investigate the upª²regulatory effect of histamine on Tollª²like receptor (TLR) expression in pulmonary epithelia cells. METHODS: TLR1ª²TLR10 mRNA expressions were determined by RTª²PCR in resting A549 cells, and by realª²time quantitive PCR in the cells following stimulation with histamine at various concentrations and at various periods of time. Furthermore, the upª²regulatory effect of histamine on TLR3 was examined by flow cytometry. RESULTS: TLR1ª²TLR10 mRNA were constitutively expressed in A549 cells. Histamine significantly enhanced TLR3 expression at both mRNA and protein levels in a concentrationª² and timeª²dependent manner. This effect of histamine was blocked by the H1 receptor antagonist. CONCLUSION: TLR3 expression can be upª²regulated by histamine in A549 cells, which suggests that excessive histamine can enhance the sensitivity of pulmonary epithelium to virus infection when the allergic diseases exist in the respiratory tract. ......