Fig 3.
Caspases are activated following infection of human neurons by rOC/ATCC and rOC/US183-241, but the induced programmed cell death is not inhibited by Z-VAD-FMK. (A and B) Differentiated LA-N-5 cells were infected with rOC/ATCC or rOC/US183-241 and treated with either the pan-caspase inhibitor Z-VAD-FMK (VAD) (A) or the caspase-9 inhibitor Z-LEHD-FMK (LEHD) (B) for 24, 48, or 72 h. Viability of infected human neurons was evaluated with the MTS-PMS assay and expressed as relative percentage compared to that of mock-infected cells. (C) Immunofluorescence of active caspase-3. Vehicle-treated (left column) and Z-VAD-FMK-treated (right column) cells were incubated with anti-activated caspase-3 antibody (green). DAPI (blue) insets demonstrate equivalent cell density in the microscope fields analyzed. Statistical significance: *, P < 0.05; **, P < 0.01; ***, P < 0.001.