This antibody reacts with the CD31-antigen, which is expressed on human thrombocytes. The monoclonal antibody reacts with thrombocytes, monocytes/macrophages and granulocytes. In immunohistology the monoclonal antibody reacts with endothelial cells histiocytes (weak) and glomeruli. The antigen is localized at regions of cell-cell contacts and may function as an adhesion molecule, mediating adhesion between leucocytes and endothelial cells, leucocytes and platelets, and endothelial cells with other endothelial cells.