In line with our in vivo results and regardless of strain genetic background, infection with ∆T mutant strains resulted in significantly higher levels of IL-1β and IL-18 secreted by BMDMs, and complementing ∆T strains with pExoT reduced the production of these pro-inflammatory cytokines (Fig. 2a–b and Supplementary Fig. 3a–b). This evidence concerns the gene IL1B and infection.