IL1B and infection: To test this, we infected LPS-primed human macrophage-like THP1 cells with S. Typhi mutants and assayed for pyroptotic cell death with lactate dehydrogenase (LDH) release and IL-1β release at 2 hours post-infection as well as cell death kinetics using SYTOX Green staining over 10 hours of infection (Fig 7A, 7B and 7C).