IL1B and infection: However, the expression of caspase-1 and IL-1β mRNA showed a “saddle pattern” of change over time post-infection; caspase-1 expression reached an initial peak at 7 d and a second peak at 28 d, while IL-1β mRNA reached a first peak at 14 d and a second peak at 28 d in both the BPG treatment and no BPG treatment subgroups (Fig. 2b, c).