SMOX and infection: To determine whether AQs are produced during infection of differentiated HBECs, differentiated Calu-3 cells in air-liquid interface cultures (Calu-3-ALI; Figure S1) were infected with PAO1 or the isogenic AQ-negative ΔpqsA mutant (Figure S2) at MOI 50 and AQs in the infected cultures were quantified by LC-MS/MS as described in Materials and Methods.