Figure 3.
Cytotoxicity in THP-1 macrophages. Vaccine strains and the parental wild-type strains have cytotoxic effects on THP-1 macrophages. THP-1 cells were infected with wild-type or vaccine strains and cell viability was measured for 5 h and compared to uninfected cells: (A) S. flexneri 2a, (B) S. flexneri 3a and (C) S. flexneri 6. Error bars depict standard deviation of three biological replicates. Optical density readings represent the colorimetric change associated with WST-1 reagent cleavage which correlates with cellular viability. Optical density was calculated by subtracting the OD600 nm value from the OD450 nm value.