To investigate whether IL-37b exhibits anti-inflammatory activity in the TLR ligand-stimulated non-CF and CF airway epithelial cells, we pretreated the C38 and IB3-1 cells with a precursor, or Val46 IL-37b before their exposure to flagellin (FLA), a ligand for TLR5, or poly(I:C), a synthetic ligand of TLR3, and then the cytokine production was measured by ELISA. Here, TLR5 is linked to cystic fibrosis.