CASP1 and infection: Although forced ubiquitous expression of caiap mRNA alone barely increased the resistance to ST infection (Figures 5D, 6A and 7A) and caspase-1 activity (Figures 5C, 6B and 7B), forced expression of caiap in macrophages, using the macrophage-specific promoter mpeg1 (27), resulted in increased resistance to ST infection (Figure 5G).