Fig. 5. Inhibition of VEGF-C_NC-induced BAE cell in vitro angiogenesis by blocking VEGFR-2 and VEGFR-3 simultaneously. Confluent BAE cell monolayers on three-dimensional collagen gels (Control) were treated for 4 days with VEGF-C_NC (100 ng/ml) alone or in combination with a neutralizing anti-human VEGFR-3 monoclonal antibody (hF4-3C5, 5 µg/ml), a neutralizing anti-human VEGFR-2 monoclonal antibody (IMC-1C11, 20 µg/ml) or a control antibody (anti-KHL, 20 µg/ml). Cell cord formation within the collagen gel was viewed by phase-contrast microscopy. Co-addition of the neutralizing anti-VEGFR-3 or anti-VEGFR-2 antibodies alone partially inhibited invasion induced by VEGF-C_NC, whereas co-addition of both antibodies completely blocked invasion induced by VEGF-C_NC. Cells treated with IMC-1C11 or hF4-3C5 alone showed no signs of cytotoxicity. No invasion occurred in untreated cultures. Bar, 100 µm.