Effect of PIC infection on caspase activation. HMEC-1s were infected with PIC at MOIs of 0.1, 1, 10 (n = 3). In addition, 10 nM of L-NAME was added prior to PIC MOI = 1 infection (n = 5). Caspase activation was fluorescently detected 72 h post-infection. * represents p < 0.05 when compared with mock-infected controls. HMEC-1s treated with L-NAME and infected with PIC were tested for significance versus HMEC-1s infected with PIC MOI = 1; results were not considered significant.