NLRP3 and infection: We infected WT and pearl mice intranasally with Lpm strain ΔflaA, which lacks flagellin and stimulates the NLRP3 inflammasome [36, 37], and 24 h post-infection measured bacterial load in lung homogenates and levels of TNFα (as a read-out for effective priming) and IL-18 (as a read-out for inflammasome activation) in the broncho-alveolar lavage (BAL).