A humanized monoclonal antibody directed against the human alpha v integrin subunit with potential antiangiogenic and antineoplastic activities. Anti-human integrin alpha v subunit monoclonal antibody EMD 525797, a chimeric antibody which includes the antigen binding sites of the anti-integrin mouse antibody 17E6, binds to and inhibits the activity of alphavbeta3 integrin (vitronectin receptor); this may result in the inhibition of endothelial cell-cell interactions, endothelial cell-matrix interactions, and integrin-mediated tumor angiogenesis and metastasis in alphavbeta3-expressing tumor cells. Alphavbeta3 integrin, a cell adhesion and signaling receptor, is expressed on the surface of tumor vessel endothelial cells and plays a crucial role in endothelial cell adhesion and migration.