To address these questions, we first examined whether TLR2 modulated melatonin biosynthesis and NLRP3 inflammasome activity by using TLR2−/− mice, and further revealed whether this effect of TLR2 was feedback regulated by melatonin by administrating exogenous melatonin or melatonin receptor antagonist luzindole in OVA-induced allergic airway inflammation.