The presence of LPS in treated samples was evaluated by Limuls Amebocyte Lysate test (LAL-Charlys River). The hemorrhagic activity of Triton-treated jararhagin was measures in the mouse skin ( Kondo et al., 1960) and cell viability assay was evaluated by MTT method ( Tanjoni et al., 2005). Jararhagin LPS-free was used for all cell culture experiments. Human vascular

endothelial cells (HUVECS) obtained from umbilical cords of newborns (Hospital Veliparib of University of São Paulo: Ethical Committee for Human Protocol: 526/04) were aseptically harvested in our laboratory as described before (Jaffe et al., 1973) and cultured on 0.1% gelatin-coated plastic bottles (75 cm2) in the presence of RPMI 1640 medium supplemented with 10% Fetal Bovine Serum (FBS), 2 mM l-glutamine, 1 mM sodium pyruvate, 100 UI/mL penicillin, 100 mg/mL streptomycin, 50 mM 2-mercaptoethanol, 5 U/mL heparin, 20 ng/mL bFGF, and 10 ng/mL EGF. The cells were used until the 5th passage. The cells were grown in 25 cm2 plastic bottles until reach a confluent monolayer and then they were

treated with different doses of jararhagin diluted in the supernatant, during 1, 3, 6, 24 or 48 h, according to the experiment. Cells treated with PBS diluted in the supernatant Target Selective Inhibitor Library cell assay were used as control group. Cell viability and cell detachment induced by jararhagin was evaluated using the MTT assay (3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide). Cells were seeded at the concentration of 5 × 104 ADP ribosylation factor cells per well in 96 well microplates, previously coated with

gelatin 1%. After 24 h, the medium was changed and supplemented with the same complements cited above, except the growth factors. The samples containing jararhagin (100, 200, 400 or 600 nM) and negative controls (PBS 1:10 in culture media or LPS 1 mg/mL) were added in the time zero and kept during the time course of the experiment (48 h) in 37 °C with 5% CO2. The total cell lyses was induced by sterile distilled water. For the experiment of cell viability, after 24 and 48 h, 20 μL/well of MTT (5 mg/mL diluted in PBS) was added to the culture medium and kept for 3 h at 37 °C. The formazan crystals resulting from MTT reduction were dissolved by addition of 100 μL of PBS containing 10% SDS and 0.01 N HCl (18 h, 37 °C and 5% CO2) and the infrared light absorption was read using an plate spectrophotometer (Multiskan EX – Thermo) at 490 nm. To quantify the cell detachment induced by jararhagin, the same procedure for cell culture was used, however after 24 or 48 h the detached cells were removed by two careful washes using PBS and the remaining cells were stained by MTT assay as described above. For both experiments, the absorbance was read on a multiwell scanning spectrophotometer (ELISA reader) using a filter of 570 nm.