IL1B and infection: To investigate whether differences in caspase-1 activation by B. pseudomallei strain E8 and B. thailandensis strain E264 might cause different IL-1β release, we determined the amount of the cytokine in cell culture supernatants of infected (MOI 50) and uninfected macrophages of caspase-1/11-deficient and wild-type mice at 12 hours post infection (Figure 2A).