The SN6 monoclonal antibody specifically reacts with human CD105 (Endoglin), a 90kDA homodimeric glycoprotein expressed on vascular endothelial cells, activated macrophages, and a subset of bone marrow cells. CD105 is a marker for tumor angiogenesis research by identifying proliferating endothelium. It is also suggested to be involved in embryonic angiogenesis and cellular adhesion.