FIGURE 4.

Activities on eukaryotic cells. A, hemolytic effects of the indicated peptides. The cells were incubated with different concentrations of the peptides, 2% Triton X-100 (Sigma-Aldrich) served as positive control. The absorbance of hemoglobin release was measured at λ 540 nm and is expressed as % of Triton X-100-induced hemolysis (note the scale of the y axis). Effects of LL-37 are shown for comparison. In B, upper panel, HaCaT keratinocytes were subjected to the indicated TFPI-peptides as well as LL-37. Cell-permeabilizing effects were measured by the LDH-based TOX-7 kit. LDH release from the cells was monitored at λ 490 nm and was plotted as % of total LDH release. Lower panel: the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay was used to measure viability of HaCaT keratinocytes in the presence of the indicated peptides (at 60 μm). In the assay, MTT is modified into a dye, blue formazan, by enzymes associated with metabolic activity. The absorbance of the dye was measured at λ 550 nm.