Human Thrombomodulin/BDCA-3 APC-conjugated Antibody

Encoded by the THBD gene, Thrombomodulin is also known as Blood Dendritic Cell Antigen 3 (BDCA‑3) and designated CD141. The deduced amino acid (aa) sequence of human THBD predicts a signal peptide (aa 1‑18) and a mature chain (aa 19‑575) that consists of the following domains: a C‑type lectin domain (aa 31‑169), EGF‑like domains (aa 241‑281, aa 284‑324, aa 325‑363, aa 365‑405, aa 404‑440, and aa 441‑481), a transmembrane domain (aa 516 to 539), and a cytoplasmic region (aa 540‑575). The region used as an immunogen consists of aa 19‑515, corresponding to the extracellular portion of the type I transmembrane protein. Predominantly synthesized by vascular endothelial cells, THBD inhibits coagulation and fibrinolysis (1‑3). It functions as a cell surface receptor and an essential cofactor for active thrombin, which, in turn, activates Protein C and Thrombin‑activatable Fibrinolysis Inhibitor (TAFI), also known as Carboxypeptidase B2 (CPB2). Activated protein C (APC), facilitated by Protein S, degrades coagulation factors Va and VIIIa, which are required for thrombin activation. Activated CPB2 cleaves basic C‑terminal aa residues of its substrates, including fibrin, preventing the conversion of plasminogen to plasmin. In addition, THBD gene polymorphisms are associated with human disease and with THBD playing a role in thrombosis, stroke, arteriosclerosis, and cancer (4). For example, increased serum levels of THBD due to protease cleavage have been associated with smoking, cardiac surgery, atherosclerosis, liver cirrhosis, diabetes mellitus, cerebral and myocardial infarction, and multiple sclerosis (5).