Development and Characterization of New Species Cross-Reactive Anti-Sialoadhesin Monoclonal Antibodies.

Sialoadhesin (Sn) is a surface receptor expressed on a subset of macrophages in steady state conditions. During inflammation and diseases, Sn is highly upregulated on macrophages and blood monocytes. Therefore, therapies using monoclonal antibodies (mAbs) to target Sn-positive (Sn) cells are a potential strategy for targeted treatment.

The novel ADAMTS13-p.D187H mutation impairs ADAMTS13 activity and secretion and contributes to thrombotic thrombocytopenic purpura in mice.

Background: Congenital thrombotic thrombocytopenic purpura (TTP) is characterized by mutations in the ADAMTS13 gene, which either impair protein secretion or influence ADAMTS13 (A Disintegrin-like And Metalloprotease domain with ThromboSpondin type-1 motif, member 13) activity. Phenotypic consequences of these mutations have not yet been evaluated in animal models for TTP.

Objectives: To identify the in vitro effect of a novel ADAMTS13 mutation and to investigate whether this mutation induces TTP in vivo.

The distal carboxyterminal domains of murine ADAMTS13 influence proteolysis of platelet-decorated VWF strings in vivo.

Background: The multidomain metalloprotease ADAMTS13 regulates the size of von Willebrand factor (VWF) multimers upon their release from endothelial cells. How the different domains in ADAMTS13 control VWF proteolysis in vivo remains largely unidentified.

Methods: Seven C-terminally truncated murine ADAMTS13 (mADAMTS13) mutants were constructed and characterized in vitro.

Von Willebrand factor: drug and drug target.

One of the key players in many thrombotic complications is von Willebrand factor (VWF), a large, multimeric glycoprotein that is present in plasma where it fulfils a crucial role in haemostasis. First, VWF recruits platelets to vascular lesions by acting as a linker molecule between the exposed collagen and free-flowing platelets in the circulation. Second, by serving as a carrier protein for the coagulation factor VIII, VWF protects this anti-haemophilic factor from rapid degradation.

Paratope and epitope mapping of the antithrombotic antibody 6B4 in complex with platelet glycoprotein Ibalpha.

The monoclonal antibody 6B4 has a potent antithrombotic effect in nonhuman primates by binding to the flexible loop, also known as the beta-switch region (amino acids 230-242), of glycoprotein Ibalpha (GPIbalpha). This interaction blocks, in high shear stress conditions, the specific interaction between GPIbalpha and von Willebrand factor suppressing platelet deposition to the damaged vessel wall, a key event in the pathogenesis of arterial thrombosis. To understand the interactions between this antibody and its antigen at the amino acid level, we here report the identification of the paratope and epitope in 6B4 and GPIbalpha, respectively, by using computer modeling and site-directed mutagenesis.