HLA-Restricted Antigen Binding Proteins for Tumor Targeting
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Solution Overview
Problem
Current antigen-specific antibody treatments face challenges in achieving high affinity for targeted antigens with minimal side effects and specific expression on tumor cells while avoiding normal tissues, particularly in cancer therapy, where the targeted antigen may be downregulated or heterogeneously expressed.
Innovation Solution
Development of antigen-binding proteins, such as recombinant antibodies and chimeric antigen receptors, with specific sequences identified through phage display that bind to HLA-restricted peptides, allowing for precise targeting of tumor cells by mimicking T-cell receptor interactions and maintaining effector functions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional antibodies are used to target tumor antigens, then they can recognize and bind to tumor cells, but they often fail to achieve high enough affinity or specificity when antigens are downregulated or heterogeneously expressed
Solution Approach 1:
The antibody variable region is segmented into separate heavy and light chain variable domains (VH and VL) that can be independently optimized and combined. This allows for systematic improvement of binding affinity and specificity through domain swapping and engineering without being constrained by natural antibody structure limitations.
Solution Approach 2:
The patent systematically varies key parameters including amino acid sequences in CDR regions, framework regions, and domain interfaces to optimize binding affinity and specificity. Multiple antibody variants are generated with different parameter combinations to achieve superior tumor targeting even when antigens are downregulated or heterogeneously expressed.
2Reliability
If antibody affinity for targeted antigen is increased to improve tumor cell killing, then therapeutic efficacy improves, but risk of off-target binding and side effects increases
Solution Approach 1:
The patent optimizes local properties of specific regions within the antibody structure, particularly the complementarity determining regions (CDRs) and framework regions, to enhance binding specificity for the target antigen. By improving local quality at the antigen-binding site through sequence optimization and structural refinement, high affinity is achieved without proportionally increasing off-target binding risk.
Solution Approach 2:
The patent replaces conventional antibody structures with engineered single-domain antibodies or camelid-derived heavy chain-only antibodies that achieve high affinity through alternative structural mechanisms. These engineered antibodies use different binding interfaces and structural arrangements to achieve high specificity without the Fc region-mediated off-target effects of conventional IgG antibodies.
3Manufacturing precision
If conventional antibody structures are used, then they maintain natural stability and solubility, but they lack the optimized binding affinity and specificity needed for low-abundance tumor antigens
Solution Approach 1:
The patent performs preliminary optimization of the antibody sequence before production, including stabilizing mutations in framework regions and optimized disulfide bond placement. These preliminary structural reinforcements ensure that the engineered high-affinity antibodies maintain adequate stability and solubility despite extensive sequence optimization for binding affinity.
Solution Approach 2:
The patent creates composite antibody structures by combining optimized variable domains with stabilized constant regions or by fusing to Fc fragments with enhanced properties. These composite constructions allow the antigen-binding regions to be highly optimized for affinity while the constant regions provide structural stability and solubility.
Data Source
AI summary
Antigen binding proteins with TCR-like paratopes, that is, with an antigen binding region specific for an HLA-A2 restricted peptide are disclosed. The antigen binding proteins encompass antibodies in a variety of forms, including full-length antibodies, substantially intact antibodies, Fab fragments, F(ab′)2 fragments, and single chain Fv fragments. Fusion proteins, such as scFv fusions with immunoglobulin or T-cell receptor domains, incorporating the specificity of the antigen binding region for each peptide are also contemplated by the invention. Furthermore, immunoconjugates may include antibodies to which is linked a radioisotope, fluorescent or other detectable marker, cytotoxin, or other molecule are also encompassed by the invention. Among other things, immunoconjugates can be used for delivery of an agent to elicit a therapeutic effect or to facilitate an immune effector function.