A549 3D aggregates showed improved characteristics as compared with monolayer cultures: formed a tighter epithelium, produced both MUC1 and MUC5AC on the apical surface of the 3D aggregates, indicating proper localization, which were more resistant to P. aeruginosa colonization and infection, and showed greater fold induction of IL-12, TNF-α, IL-10, and IL-6. The gene discussed is MUC1; the disease is infection.