Structure-Sensitive Peptide Antigen for VWF Diagnosis
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Solution Overview
Problem
Current diagnostic and treatment methods for von Willebrand factor (VWF)-related blood diseases are hindered by non-physiological conditions, interference from antibodies, and the lack of targeting ability and durability in existing antibody drugs, which limits their effectiveness and safety for a wider range of patients.
Innovation Solution
A structure-sensitive peptide antigen derived from the A1 domain of human VWF, specifically located in the loop region between the β3 fold and α2 helix, is used to develop an antibody that only recognizes active VWF, allowing for targeted diagnosis and treatment while minimizing thrombotic risks and medication dosage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If caplacizumab binds to VWF to block platelet binding, then thrombotic symptoms are reduced, but VWF level declines causing unpredictable bleeding risks and poor durability
Solution Approach 1:
The patent applies local quality by designing an antibody that specifically targets the A1 domain of VWF, which is the local region responsible for platelet binding. This localized targeting allows the antibody to block thrombotic activity without causing systemic clearance of all VWF, thereby reducing bleeding risks while maintaining durability.
Solution Approach 2:
The patent segments the VWF molecule by focusing on the A1 domain (amino acids 449-652) as a distinct functional unit. By developing an antibody that specifically recognizes this segmented region, the therapy can selectively inhibit platelet binding without affecting other VWF functions, resolving the contradiction between thrombosis prevention and bleeding risk.
2Object-affected harmful factors
If caplacizumab is used to treat VWF-related diseases, then thrombosis is inhibited, but medication dosage must be large and durability is poor
Solution Approach 1:
The antibody specifically targets the A1 domain structure, creating a localized intervention that is highly specific and potent. This precise local targeting improves medication durability by reducing off-target effects and the need for high dosages, allowing for sustained therapeutic action.
Solution Approach 2:
The patent changes the binding parameter from non-specific VWF binding to specific A1 domain binding. This parameter change in binding specificity leads to improved pharmacokinetic properties, including longer duration of action and reduced dosage requirements, thereby resolving the durability contradiction.
3Measurement precision
If diagnostic preparations are used under non-physiological conditions, then VWF activity can be measured, but diagnostic results are prone to interference and reliability is poor
Solution Approach 1:
The patent changes the diagnostic approach by using an antibody that recognizes the activated conformation of the A1 domain. This parameter change in recognition specificity allows for accurate measurement of VWF activity under physiological conditions, eliminating interference from antibodies and improving diagnostic reliability.
Data Source
AI summary
The present invention discloses a polypeptide antigen sequence, its spatially sensitive position in von Willebrand factor (VWF), and use thereof in the production of preparations for the diagnosis and/or treatment of VWF-related blood diseases. The polypeptide antigen comprises the amino acid sequence as shown in SEQ ID NO: 1, or a biologically active fragment or a variant thereof. The spatial position of the polypeptide transits from non-solvent exposure to solvent exposure when VWF is in activation process upon exposing to blood shear stress, so as to be recognized by an antibody. The antibody that recognizes the active state of VWF prepared by using the polypeptide antigen is useful in diagnosing and treating a variety of VWF-related diseases.