Specific CD8 Antigen-Binding Constructs for Detection and Rapid Clearance
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Solution Overview
Problem
Current technologies lack effective antigen binding constructs that specifically target CD8, a transmembrane glycoprotein crucial for T-cell activation and localization, which is essential for understanding immune responses and potential therapeutic targeting.
Innovation Solution
Development of antigen binding constructs such as humanized cys-diabodies and minibodies that bind to CD8, including specific HCDR and LCDR sequences, enabling detection and therapeutic targeting of CD8+ cells.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional antibody formats are used to target CD8, then detection capability is provided, but the constructs lack rapid clearance and enhanced specificity
Solution Approach 1:
The patent segments the antibody structure into different formats including minibodies (composed of VL-VH-CH3 domains) and cys-diabodies (comprised of two scFv units linked by disulfide bonds). This segmentation creates smaller molecular weight constructs that exhibit rapid serum clearance while maintaining CD8 binding specificity, resolving the contradiction between detection capability and clearance rate
Solution Approach 2:
The patent alters key parameters of the antibody constructs by humanizing the variable regions and modifying the constant regions to create minibody and cys-diabody formats. These parameter changes result in constructs with enhanced specificity for CD8 and optimized pharmacokinetic properties including rapid clearance, while preserving the essential detection function
2Ease of manufacture
If full-length antibodies are used for CD8 targeting, then therapeutic targeting is achieved, but the molecular weight is too large for optimal tissue penetration and clearance
Solution Approach 1:
The patent extracts and removes portions of the full-length antibody structure, specifically eliminating the Fc region and portions of the constant domains to generate minibodies and cys-diabodies. This extraction reduces molecular weight from the typical 150 kDa of full-length antibodies to approximately 50-70 kDa, improving tissue penetration and clearance while retaining therapeutic targeting capability through the preserved variable regions
Solution Approach 2:
The patent divides the full-length antibody into functional segments, separating the antigen-binding variable regions from the constant Fc regions. This segmentation creates smaller constructs with reduced molecular weight that maintain therapeutic functionality while achieving optimal pharmacokinetic properties for tissue penetration and clearance
Data Source
AI summary
Antigen binding constructs that bind to CD8, for example antibodies, including antibody fragments (such as scFv, minibodies, and cys-diabodies) that bind to CD8, are described herein. Methods of use are described herein.