FIG. 4.

Kinetics of the SphH-mediated cytotoxic effect on mammalian cells. Kinetics of cytotoxicity induced by the 0.1 M NaCl SphH eluate on Vero, A549, H1299, and L132 cells were determined. Cells began to die 2 h after addition of the SphH, and total cell lysis occurred after 6 to 8 h. Cytotoxicity was not induced by E. coli lysate harboring pBS vector which was used as a negative control (data not shown). Cells were cultured as described in Materials and Methods. Cytotoxicity of mammalian cell lines was assayed by measuring the LDH released from the lysed cells and is expressed as a percentage of cell lysis, as indicated in Materials and Methods. Results represent the means ± standard deviations (error bars) of triplicates.