Figure 4. Salmonella type III secretion protein and invasion factor SipB induces mitochondrial depolarization and caspase-1 dependent IL-1β secretion.
(A) Three hour-LPS-primed Nlrp3–/– BMDM were exposed to wild-type (St wt) or nonflagellated mutant St (St ΔfljB/fliC) (MOI=5) and IL-1β was quantified in culture supernatants by ELISA.
(B and C) Three hour-LPS-primed BMDM were exposed to various strains of St (MOI=5) and (B) cell viability was determined by LDH release assay or (C) ΔΨm was measured by TMRM incorporation.
(D and E) IL-1β or TNF-α were quantified in culture supernatants by ELISA in (D) WT and Casp1–/– macrophages or in (E) WT and Bcl-2 overexpressing macrophages that were exposed to St (MOI=5).
Data shown are representative of three or more independent experiments (means ± SD).* p<0.05, ** p< 0.01, *** p<0.001.