CD105 is also known as Endoglin and it modulates cellular response to TGF-ß, involved in vascular development and remodeling. It is a type I integral membrane homodimer protein with subunits of 90 kD found on vascular endothelial cells, bone marrow stromal cells, and hematopoietic stem/progenitor cells. CD105 is weakly expressed on stromal fibroblasts. It is also expressed on activated monocytes and tissue macrophages. Expression of CD105 is increased on activated endothelium in tissues undergoing angiogenesis, such as in tumors, or in cases of wound healing or dermal inflammation. CD105 is a component of the TGF-β receptor system in human umbilical vein endothelial cells and binds TGF-β1 and β3 with high affinity but does not bind to TGF-β2.
Anti-CD105-SAP is a bonded conjugate of a mouse monoclonal antibody to human CD105 and the secondary conjugate Streptavidin-ZAP (IT-27) containing the ribosome-inactivating protein, saporin. It eliminates cells expressing human CD105 (Endoglin).