CASP1 and infection: In contrast, a significant increase in caspase-1 enzyme activity was observed in cells infected with the HSV-1ΔICP27 mutant vector from 8 h.p.i. compared with both untreated cells and cells infected with HSV-1 w.t. To see whether the effect of ICP27 on caspase-1 could depend on the AIM 2 sensor protein, we evaluated both caspase-1’s expression (Figure 6D,E) and activity (Figure 6F) by treating cells with the AIM 2 inhibitor ODN TTAGGG (A151) prior to infection.