SMOX and infection: Nevertheless, since PAO1 and ΔpqsA did not noticeably differ in their ability to induce cytokine production in this acute infection model in which AQ levels reached concentrations of 2.5 μM for HHQ and 2 μM for PQS, it is possible that PQS could only exert its immunomodulatory properties during PAO1 infection at higher concentrations (≥2 μM).