Effects of IgGs on angiogenesis. (A) Time-course of mean endothelial vessel length for HUVECs treated with phosphate-buffered saline (PBS), siCtrl, siFZD4, siERG, 30 µM Suramin or 1 µM LGK974. Bars represent mean ± s.e.m., n = 4 independent experiments. **P < 0.01, two-tailed, unpaired t-test. (B) Time-course of mean endothelial vessel length for HUVECs treated with PBS or 300 nM IgG F2.A, F2 or OMP-18R5. Bars represent mean ± s.e.m., n = 4 independent experiments. ***P < 0.001, two-tailed, unpaired t-test.