FIG. 4.

Effects of soluble glycoproteins, virus-like particles, and TNF-α on endothelial barrier function. Confluent endothelial cell monolayers were treated with soluble glycoproteins (A), VLPs (1 particle/cell) (B), or different doses of TNF-α (C), and the TER was measured using impedance spectroscopy. Treatment of endothelial cells with sGP administered at 10 or 50 μg/ml or with Δ-peptide administered at 50 μg/ml showed no significant long-lasting changes in TER (A). Purified HA-peptide served as a negative control and was added at an equivalent concentration. In contrast to VLP_VP40- and mock-treated endothelial cells, treatment with VLP_VP40/GP resulted in a decrease in the endothelial barrier function (B). Change in barrier function was significant (P < 0.05) from the time points marked by asterisks. In addition, confluent endothelial monolayers were treated with increasing concentrations of TNF-α, and a dose-dependent decrease in TER was observed (C).