Fabs-in-Tandem Immunoglobulins for Reliable Dual Antigen Binding
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for generating bispecific or multispecific antibodies are inefficient and lack the ability to produce single molecular entities with dual antigen binding functions effectively.
Innovation Solution
The development of multivalent and multispecific binding proteins, specifically Fabs-in-tandem immunoglobulins (FIT-Igs), which can bind two or more antigens or epitopes, using a combination of polypeptide chains and optionally an Fc region, with various linker options for optimal expression and functionality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional methods (quadroma technology, chemical conjugation) are used to generate bispecific antibodies, then bisspecific antibodies can be produced, but the process is inefficient and cannot effectively produce single molecular entities with dual antigen binding functions
Solution Approach 1:
The invention divides the antibody molecule into separate functional segments: two distinct Fab fragments (each capable of binding different antigens) connected by a flexible linker to form a single-chain Fv (scFv) structure. This segmentation allows each Fab to maintain its antigen-binding specificity while being integrated into a unified molecular entity that can simultaneously target multiple antigens, directly addressing the need for efficient production of functional bispecific antibodies.
Solution Approach 2:
The invention merges two separate Fab fragments into a single continuous polypeptide chain through the linker connection, creating a unified scFv molecule. This merging approach consolidates the dual antigen-binding capabilities into a single molecular entity, improving productivity by eliminating the need for separate production and conjugation steps while ensuring reliable formation of functional bispecific structures.
2Device complexity
If tandem scFv molecules are constructed with peptide linkers, then the structure is simplified, but the linker length and composition must be optimized to ensure soluble and active form expression in bacteria
Solution Approach 1:
The invention systematically varies the linker parameters (length, amino acid composition, flexibility) to optimize the scFv structure for bacterial expression. By adjusting these parameters, the molecule achieves the right balance between structural simplicity and functional performance, ensuring proper folding, solubility, and antigen-binding activity in the bacterial expression system.
Solution Approach 2:
The invention uses phage display technology to create a library of scFv molecules with randomized linkers, then selects and replicates the optimal linker sequences that produce soluble and active forms. This copying approach allows rapid identification and propagation of the most effective linker designs without requiring exhaustive manual optimization of each possible linker variant.
3Device complexity
If the linker connecting Fab fragments is made very short or very long, then the structure is simplified or flexible, but expression in soluble and active form is compromised
Solution Approach 1:
The invention identifies and implements optimal linker length parameters that balance structural simplicity with functional reliability. The linker is designed to be long enough to allow proper Fab fragment folding and antigen binding, yet short enough to maintain molecular compactness and expression efficiency in bacterial systems.
Solution Approach 2:
The linker acts as an intermediary element between the two Fab fragments, providing the necessary spatial separation and flexibility while maintaining overall molecular integrity. The optimized linker serves as a mediator that enables both Fab fragments to function independently for antigen binding while being integrated into a single expressible molecular entity.
Data Source
AI summary
The present invention provides multivalent and multispecific binding proteins that are capable of binding two or more antigens, or two or more epitopes. The present invention also provides methods of making and using such multivalent and multispecific binding proteins, including methods of using such binding proteins for prevention or treatment of various diseases, or for detecting specific antigens in vitro or in vivo.