MUC5AC and infection: We also report that deletion of FleA in Aspergillus fumigatus conidia markedly decreases mucin binding and that this role for FleA is conserved in the pathogenic A. flavus. We conclude that a range of sterically available fucosylated glycans in mucins can act as FleA ligands and the airway mucus gel is a powerful “sticky” barrier that can capture and remove conidia to guard against invasive infection.