B7-H3 Nanobody Engineering for High-Affinity Solid Tumor Targeting
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Solution Overview
Problem
Current technologies face limitations in accessing and generating high-affinity human domain antibodies for therapeutic applications, particularly for targeting B7H3, which is expressed on various solid tumors, due to resource accessibility and affinity challenges.
Innovation Solution
Development of camel single-domain VHH monoclonal antibodies and rabbit VH single-domain antibodies that specifically bind B7H3 with high affinity, along with the creation of chimeric antigen receptor (CAR) T cells and various antibody conjugates for targeted cancer therapy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional whole IgG antibodies are used, then high affinity binding to B7H3 is achieved, but tissue penetration and solubility are limited
Solution Approach 1:
The patent extracts and utilizes only the variable heavy chain (VH) domain from conventional IgG antibodies to create single-domain antibodies. This extraction of the essential antigen-binding component eliminates the need for the full IgG structure, achieving high binding affinity while dramatically reducing molecular size from ~150 kDa to ~15 kDa, thereby improving tissue penetration and solubility.
Solution Approach 2:
The patent segments the conventional IgG antibody into independent single-domain units (VH, VL, VHH). These segmented domains can function independently as nanobodies, maintaining antigen-binding capability while enabling better tissue penetration and reduced immunogenicity compared to full IgG molecules.
2Stability of the object's composition
If camelid VHH domain antibodies are used, then solubility and thermal stability are improved, but access to high-affinity human domain antibodies remains limited
Solution Approach 1:
The patent creates human VH domain antibody copies that replicate the successful structural features of camelid VHH domains. By copying the stabilizing framework region characteristics from camelid VHH into human VH domains, the invention achieves high thermal stability and solubility using human sequences, thereby improving resource accessibility and ease of manufacture while maintaining the stability benefits.
Solution Approach 2:
The patent systematically varies framework region parameters in human VH domains to optimize stability. By changing specific amino acid residues in the framework regions (such as introducing disulfide bonds, optimizing hydrophobic packing, and adjusting surface charge distribution), the invention achieves camelid-like thermal stability and solubility in human domain antibodies, making them more accessible for therapeutic development.
3Length of moving object
If single-domain antibodies are developed, then tissue penetration and solubility are improved, but affinity and specificity challenges remain
Solution Approach 1:
The patent employs preliminary action through extensive in silico screening and in vitro selection processes before final antibody development. By pre-screening large libraries of human VH domain sequences using computational methods and progressively enriching for high-affinity binders through multiple rounds of selection, the invention identifies and develops single-domain antibodies with both high affinity and specificity, overcoming the typical affinity limitations of nanobodies.
Data Source
AI summary
Single-domain monoclonal antibodies that specifically bind B7H3 (also known as CD276) are described. The single-domain antibodies include camel VHH and rabbit VH domain nanobodies selected from phage display libraries. Chimeric antigen receptors (CARs) and other antibody conjugates targeted to B7H3 are also described. The single-domain antibodies and conjugates thereof can be used for the diagnosis and treatment of B7H3 expressing solid tumors.