IL6 and infection: Fig 4 showed that the expressions of IL-1β and IL-6 increased at 10 h post-infection with A. fumigatus in HCECs compared with the control group. Blockage of IDO by 1-MT further increased the production of these cytokines compared with the production in the A. fumigatus infection group (Fig 4A and 4B). Meanwhile, the concentration of IL-1β and IL-6 in the supernatant was also up-regulated, which was consistent with the change of IDO mRNA levels (Fig 4C and 4D).