Production of neutralizing monoclonal antibody against human vascular endothelial growth factor receptor II.

AIM To prepare neutralizing monoclonal antibody (mAb) against extracellular immunoglobulin (Ig)-like domain III of vascular endothelial growth factor receptor KDR and study its biological activity. METHODS Soluble KDR Ig domain III (KDR-III) fusion protein was expressed in E Coli and purified from the bacterial periplasmic extracts via an affinity chromatography. Monoclonal antibodies against KDR-III were prepared by hybridoma technique. ELISA and FACS analysis were used to identify its specificity. Immunoprecipitation and [3H]-thymidine incorporation assay were also used to detect the activity of anti-KDR mAb blocking the phosphorylation of KDR tyrosine kinase receptor and the influence on vascular endothelial growth factor-induced mitogenesis of human endothelial cells. RESULTS A monoclonal antibody, Ycom1D3 (IgG1), was generated from a mouse immunized with the recombinant KDR-III protein. Ycom1D3 bound specifically to both the soluble KDR-III and the cell-surface expressed KDR. Ycom1D3 effectively blocked VEGF/KDR interaction and inhibited VEGF-stimulated KDR activation in human endothelial cells. Furthermore, the antibody efficiently neutralized VEGF-induced mitogenesis of human endothelial cells. CONCLUSION Our results suggest that the anti-KDR mAb, Ycom1D3, has potential applications in the treatment of cancer and other diseases where pathological angiogenesis is involved.