Abstract: Objective: To determine the effect of Aspergillus fumigatus on the production of interleukin-6 and activation of IκBɑ in an acute monocytic leukemia cell line THP-1. Methods： THP-l cells were cultured in vitro and divided into 106 CFU/mL and 107 CFU/mL A.fumigatus group, 100 μg/mL β-Glucan control group and blank control group. The level of IL-6 mRNA and protein was detected by RT-PCR and ELISA respectively. The level of IκBɑ and phosphorylated IκBɑ was detected by Western blot. Results：The experimental concentration was selected to be 107 CFU/mL, because the level of IL-6 mRNA in the 106 CFU/mL A.fumigatus group was lower than that in the 107 CFU/mL group. The levels of IL-6 mRNA and protein in the 107 CFU/mL A. fumigatus group were 209.38 ± 25.35 and 879.86±32.35 ng/L, which were higher than that in the blank control group (1.19 ± 0.36 and 10.67±0.17 ng/L) , with significant differences (Ps<0.05). The level of phosphorylated IκBɑ protein was increased significantly when induced by 107 CFU/mL A.fumigatus and was decreased when induced by NF-κB signaling pathway inhibitor of bay 11-7082. Conclusion：A. fumigatus stimulates the secretion of IL-6 in human THP-1 cells through activating IκBɑ.

Key words: Aspergillus fumigatus, THP-1 cells line, NF- κB