Anti-GPC3 Antibody scFv Epitope Specificity
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Solution Overview
Problem
Existing anti-GPC3 antibodies, such as GC33 and GC199, recognize specific epitopes on GPC3, limiting their ability to bind effectively in the form of single chain antibodies to GPC3 localized on cell membranes, and there is a need for a more specific and effective method for detecting GPC3 for cancer treatment and diagnosis.
Innovation Solution
A novel anti-GPC3 antibody is developed using a phage display method, where an immune library of antibody genes from mice immunized with full-length human GPC3 is synthesized, forming a single chain antibody library that is expressed on phage surfaces and selected using biopanning with recombinant full-length human GPC3 and GPC3-expressing cell lines, allowing for specific binding to GPC3 even in the form of scFv.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If existing anti-GPC3 antibodies (GC33, GC199) are used, then specific epitope recognition is achieved, but binding effectiveness to cell membrane-localized GPC3 is limited
Solution Approach 1:
The patent changes the structural parameters of the antibody by developing a single-chain antibody (scFv) format with specific CDR sequences that differ from existing antibodies. This structural parameter change enables the antibody to maintain epitope recognition specificity while achieving effective binding to cell membrane-localized GPC3, resolving the contradiction between specificity and binding effectiveness.
2Adaptability or versatility
If single chain antibody format is used, then simplicity and versatility are improved, but binding capability to GPC3 on cell membranes is insufficient
Solution Approach 1:
The patent optimizes the single-chain antibody format by designing specific CDR sequences (H1, H2, H3, L1, L2, L3) that are tailored for GPC3 recognition. This parameter optimization maintains the simplicity and versatility of the scFv format while achieving reliable binding capability to GPC3 on cell membranes, thus resolving the contradiction between format flexibility and binding capability.
3Ease of manufacture
If conventional antibody preparation methods are used, then established protocols are followed, but ability to recognize novel epitopes is limited
Solution Approach 1:
The patent employs phage display technology to preliminarily screen and select antibody variants with novel epitope recognition capabilities before final antibody production. This preliminary action enables the discovery of antibodies recognizing novel GPC3 epitopes while maintaining standardized manufacturing protocols, resolving the contradiction between protocol standardization and epitope recognition versatility.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The novel antibody demonstrates excellent cytotoxic activity and IFN-γ production in CAR-T cells, making it suitable for cancer immunotherapy and effective in detecting GPC3, offering improved specificity and efficacy over existing antibodies.
Implementation Method 1
an immune library of antibody genes from mice immunized with full-length human GPC3 is synthesized, forming a single chain antibody library that is expressed on phage surfaces and selected using biopanning
Data Source
AI summary
An object of the present invention is to provide: an anti-GPC3 antibody that recognizes an epitope different from that for existing antibodies (e.g., GC33 and GC199) and can specifically bind, even in the form of single chain antibody, to GPC3 localized on a cell membrane; CAR comprising the anti-GPC3 single chain antibody; an immunocompetent cell expressing the CAR; a gene of the anti-GPC3 antibody or a gene of the CAR; a vector comprising the anti-GPC3 antibody gene or the CAR gene; a host cell in which the vector has been introduced; a method for specifically detecting GPC3; and a kit for specifically detecting GPC3. An antibody comprising particular heavy chain CDR1 to CDR3 and particular light chain CDR1 to CDR3 defined in claim 1, and specifically binding to a human-derived GPC3 polypeptide specifically binds to GPC3 localized on a cell membrane. CAR-immunocompetent cells prepared on the basis of CAR comprising such single chain antibody are useful for cancer immunotherapy.