The recombinant protein was maintained at −80 °C and diluted in sterile phosphate buffered saline (PBS). Polyoma middle T oncogene-transformed mouse endothelioma cells derived from thymus (t-End) (Willians et al., 1988) were cultured in RPMI 1640 supplemented with Protein Tyrosine Kinase inhibitor 10% fetal bovine serum (FBS) in a 5% CO2, humidified atmosphere, at 37 °C. Cells were used in the 3rd passage. t-End cells were used to carry out the in vivo and in vitro studies in mice, and the expression of PECAM-1 was determined before the beginning of assays, which provided data about the responsiveness of the cell strain to be employed.

The dorsal skinfold chamber was implanted in male Swiss mice under anesthesia, as previously described by Harder et al. (2004). Amblyomin-X (1, 10 or 100 ng/10 μl) or PBS was topically applied and in sequence VEGF-A (10 ng/10 μl) or PBS (10 μl) was also locally applied. This treatment schedule was carried out on the 3rd, 5th and 7th days after chamber implantation. Animals were immobilized in a polycarbonate tube and the microcirculatory network in the windows was digitized using intravital microscopy equipment (Carl Zeiss, Germany) and photographed using a digital camera (Sony–Cyber-Shot – 7.2 Mega Pixels/Optical

3X, Japan). The images obtained before (day 3) and after the treatments (day 9) were quantified according to Dellian et al. (1996). Results were expressed as percentage of vessels in comparison to the control find more group of animals (PBS-treated animals). Fertilized chicken eggs were incubated (65% humidity, 37 °C), and on 11th day of incubation, a sterile cellulose disc (2 mm) was placed on the CAM and Ringer solution (10 μl, control), Amblyomin-X (100 ng/10 μl) with or without VEGF-A (0.25 ng/10 μl) was subsequently applied topically. Treatments were daily

until the 14th day. The discs were removed and photographed with a digital camera coupled to a magnifying glass (Nikon, magnification 1×). Quantification of CAM vascular network was assessed by counting the number of vessels present on the disc area. Results were expressed as percentage of vessels in comparison to control membranes, treated with Ringer PLEK2 solution. All experiments were conducted with a FACS Canto Flow Cytometer (Becton Dickinson, Mountain View, CA, USA) and analyzed using the Flow Jo (version 9.1) software. Data from 10.000 cells were obtained and only the morphologically viable endothelial cells were considered in the analysis. t-End confluent cells were incubated with PBS or Amblyomin-X (100 ng/ml) in medium supplemented with 10 or 1% BSA. Afterwards at 72 h, cells were harvested and necrosis and apoptosis were measured by adding propidium iodide (PI) or annexin-V, respectively. Cell proliferation was measured in adherent t-End cells labeled with carboxyfluorescein diacetate succinimidyl ester (CFSE) according to the manufacturer’s instructions.