CASP1 and infection: However, in the presence of LL-37, a 3 hour infection with PAO1 led to an increase in caspase-1 activated NHBE cells (to ~16%; Fig 4A) and 16HBE14o- cells (S2 Fig), significantly greater than to LL-37 or PAO1 alone, with the same synergistic pattern observed as for IL-1β release.