Evaluation of a ricin vaccine candidate (RVEc) for human toxicity using an in vitro vascular leak assay

► RVEc showed no signs of adverse activity on HUVE cells as measured by changes in trans-endothelial electrical resistance (TEER). ► No cytotoxicity was visible at 24 h with 0.6 or 9 μM of RVEc under light microscopy. ► Flow cytometric analysis showed binding of RT, slight binding of RTA and no binding of RVEc vaccine to endothelial cells. ► In vitro cell-based assay demonstrated no discernable adverse events of the RVEc vaccine on human endothelial cells.