Abstract
Immune thrombocytopenia (ITP) is an autoimmune bleeding disorder characterized by low platelet count and presence of IgG autoantibodies to platelet surface glycoproteins, such as IIbβ3 and GPIb/IX. Our previous work has shown that platelets in ITP patients exist in an activated state. Two different marker-based approaches are used to study the course of platelet activation: (1) binding of PAC-1 antibody, signifying a change in αIIbβ3 conformation, and (2) expression of P-selectin, signifying alpha granule content release from platelets. Here, we describe the development of a new scFv antibody (R38) that, compared with PAC-1, appears to better distinguish between platelets of ITP patients and healthy controls. Notably, R38 was generated using commercially sourced resting-state integrin that was coated on a microtiter plate. Its ability to distinguish between ITP patients and healthy controls thus suggests that inadvertent integrin activation caused by coating involves a conformational change and exposure of a cryptic epitope. This report also describes for the first time the potential use of an scFv antibody in the immunodiagnosis of platelet activation in ITP patients.
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Disclosure of Potential Conflicts of Interest
No potential conflicts of interest were disclosed.
Acknowledgments
PB thanks the UGC for providing fellowship. Thermo Fisher Scientific (Bangalore, India) is thanked for LC-MS MS data and analysis.
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