CASP1 and infection: Next, we used the pan-caspase inhibitor Q-VD-OPh (PINH; Supplementary Fig. 4A,B) as well as the specific caspase-1 inhibitor Ac-YVAD chloromethylketone (Ac-YVAD-CMK, C1INH; Fig. 3a,b), which was shown to inhibit the activity of recombinant fish caspase-1 (refs 19, 20), and it was found that bath treatment with either inhibitor increased the susceptibility of zebrafish larvae to ST infection and, more importantly, fully abrogated the Gbp4-mediated increased infection resistance (Supplementary Figs 3A and 4A).