Antibody Fragment Generation for Solid Tumour Targeting
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Solution Overview
Problem
Current monoclonal antibody therapies for treating solid tumours face challenges due to the large size of antibody molecules hindering penetration, tumour heterogeneity, and the interference of soluble shed antigens, leading to reduced efficacy and increased side effects.
Innovation Solution
Development of a method to generate antibodies that can distinguish between the membrane-bound and soluble forms of an antigen by recognizing differences in conformation, allowing for targeted delivery to tumour cell membranes while avoiding soluble forms in circulation, using a process involving immunization with both forms of the antigen and administration of chemotherapeutic agents to deplete relevant B cells.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional monoclonal antibodies are used to treat solid tumours, then the antibody can bind to the antigen target, but the large size of the antibody molecule hinders penetration into the tumour mass
Solution Approach 1:
The patent segments the antibody molecule into smaller fragments (scFv, Fab, F(ab')2) that retain antigen-binding capability but can penetrate tumour mass more effectively. This segmentation resolves the contradiction by maintaining binding specificity while reducing molecular size for better penetration.
Solution Approach 2:
The patent changes the physical parameter of antibody size by using engineered antibody fragments instead of full-length antibodies. This parameter change allows the therapeutic agent to penetrate the dense tumour microenvironment while maintaining the ability to specifically bind the target antigen.
2Reliability
If conventional monoclonal antibodies are used, then the antibody can target the antigen, but soluble shed antigens bind the therapeutic antibody and reduce efficacy
Solution Approach 1:
The patent extracts the Fc region from the antibody molecule, creating Fc-free antibody fragments. This extraction eliminates the Fc-mediated clearance pathway that would otherwise remove the antibody-antigen complex from circulation, thereby preventing soluble shed antigens from effectively competing for binding and reducing therapeutic efficacy.
Solution Approach 2:
The patent converts the potential harm of soluble antigen binding into a benefit by designing fragments that preferentially bind membrane-bound antigen. The soluble shed antigens, which would normally compete and reduce efficacy, are effectively excluded because the fragment-antigen binding occurs primarily at the cell surface where membrane-bound antigen is present.
3Reliability
If antibody conjugation with killing agents is used, then penetration and tumour heterogeneity issues are addressed, but the non-specific side effects of radio-isotope, drug or toxin increase
Solution Approach 1:
The patent applies local quality by conjugating killing agents (radio-isotopes, toxins, chemotherapeutic drugs) to localized antibody fragments that specifically target tumour cells. The small size of the fragments enables better penetration into the tumour mass, delivering the killing agent directly to the target site and reducing non-specific side effects compared to conventional full-length antibody conjugates.
4Reliability
If large amounts of antibody are administered to address penetration issues, then tumour cell coverage improves, but undesirable side effects increase
Solution Approach 1:
The patent uses segmented antibody fragments instead of full-length antibodies. These fragments have smaller molecular weights that facilitate deeper penetration into the tumour mass, allowing effective tumour coverage at lower administered doses and thereby reducing dose-dependent side effects.
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
This approach enables antibodies to effectively target tumour cells with reduced side effects and increased efficacy, potentially allowing for lower doses and more cost-effective treatments, as they specifically bind to membrane-bound antigens without binding to soluble forms.
Implementation Method 1
administering to the animal a chemotherapeutic agent which selectively kills rapidly dividing cells
Implementation Method 2
generating an antibody which can discriminate between the membrane bound form of an antigen and the soluble form of the antigen by recognising a difference in conformation between the membrane bound form of an antigen and the soluble form of the antigen
Data Source
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AI summary
The present invention discloses a reliable and efficient method of generating an antibody which can discriminate between the membrane bound form of an antigen and the soluble form of the same antigen. Said method comprises the steps of: (i) immunizing an animal with a first antigen which comprises either the membrane bound form or the soluble form of the antigen; (ii) administering to the animal an agent which selectively kills rapidly dividing cells; (iii) when the first antigen of step (i) comprises the soluble form, immunizing the animal with a second antigen which comprises the membrane bound form of the antigen, or when the first antigen of step (i) comprises the membrane bound form, immunizing the animal with a second antigen which comprises the soluble form of the antigen; and (iv) screening for an antibody which can bind to the second antigen but which does not bind to the first antigen.