Cell Surface Capture Proteins for Bispecific Antibody Clone Screening
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Solution Overview
Problem
Existing methods for isolating high-expression recombinant cell lines producing heterodimeric proteins, such as bispecific antibodies, are laborious, inefficient, and prone to losing rare high-expression cells, with current flow cytometry methods being inadequate for diverse protein expression and diffusion issues.
Innovation Solution
A high-throughput screening method using cell surface capture proteins that bind to proteins of interest, allowing direct detection and isolation of cells expressing high levels of heterodimeric proteins by transfecting cells with nucleic acids encoding these capture molecules, followed by detection with specific molecules and isolation based on binding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If standard methods for isolating high expression cells (collection of cell pools, hand-picking colonies, limited dilution) are used, then the isolation process can be performed with simple equipment and procedures, but the process is laborious, inefficient, and the number of clones that can be analyzed is limited to a few hundred
Solution Approach 1:
The patent replaces manual mechanical methods (hand-picking colonies, limited dilution) with flow cytometry-based automated sorting. Cells are labeled with fluorescently conjugated antibodies that bind to the protein of interest, allowing automated detection and sorting of high-expression cells based on fluorescence intensity, thereby increasing productivity and reducing time
Solution Approach 2:
The patent introduces fluorescently conjugated antibodies as intermediaries that bind to the protein of interest on the cell surface. These antibodies serve as mediators that enable indirect detection of protein expression levels through fluorescence, allowing flow cytometry to identify and sort high-expression cells efficiently
2Reliability
If many individual clones are screened to identify rare high expression integration events, then the probability of finding high expression cell lines increases, but the labor and time required increases proportionally
Solution Approach 1:
The patent replaces labor-intensive manual screening of many clones with automated flow cytometry sorting. By labeling cells with fluorescent antibodies and using flow cytometry to detect fluorescence intensity, the system can rapidly screen and sort thousands of clones in parallel, maintaining high reliability while dramatically increasing productivity
Solution Approach 2:
The patent adds the dimension of fluorescence detection to the screening process. Instead of relying on traditional methods that screen clones sequentially or in small pools, the invention uses fluorescence intensity as an additional parameter to directly identify and sort high-expression cells, enabling parallel processing of large numbers of clones
3Quantity of substance
If cell pools or individual clones are collected and expanded before screening, then sufficient cell numbers are obtained for analysis, but rare high expression cells are lost to faster growing low expression cells
Solution Approach 1:
The patent performs preliminary labeling of cells with fluorescent antibodies before expansion and screening. By identifying and sorting high-expression cells based on fluorescence intensity at an early stage, the method ensures these rare cells are captured and expanded separately, preventing them from being lost during bulk culture expansion where faster-growing low-expression cells would dominate
4Productivity
If flow cytometry is used to screen large numbers of individual clones, then screening capability is improved, but current methods remain inadequate due to diffusion of the protein of interest between cells of different characteristics
Solution Approach 1:
The patent uses fluorescently conjugated antibodies as intermediaries that bind specifically to the protein of interest on the cell surface. These antibodies prevent diffusion of the native protein between cells by immobilizing it with high affinity, while the fluorescent label enables precise flow cytometry detection of expression levels without the diffusion problem
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
Enables rapid and efficient isolation of high-expression cells producing heterodimeric proteins, such as bispecific antibodies, by directly screening on a single-cell basis, reducing the risk of losing high-expression cells and improving the screening of large numbers of clones.
Implementation Method 1
a cell surface capture molecule, which is capable of binding a secreted protein of interest
Implementation Method 2
a detection molecule, which binds the POI
Data Source
AI summary
Recombinant cell surface capture proteins and detection molecules that are useful for isolating and detecting cells that produce a secreted heterodimeric protein of interest (POI) that has an immunoglobulin CH3 domain and/or substituted CH3 domain are provided. Recombinant cell surface capture proteins and detection molecules that isolate and detect bispecific antibodies are also provided. The invention also provides recombinant antigen-binding proteins that are capable of recognizing and binding to proteins of interest that contain a CH3 domain and/or a modified CH3 domain, such as a CH3 domain with or without amino acid substitutions at H95 and Y96 (IMGT).