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Bacterial Inner-membrane Display for Screening a Library of Antibody Fragments
Published on: October 15, 2016
In vitro evolution of single-chain antibodies using mRNA display
Isao Fukuda1, Kanehisa Kojoh, Noriko Tabata
1Department of Biosciences and Informatics, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-8522, Japan.
Nucleic Acids Research
|October 3, 2006
Summary
The mRNA display method enables in vitro evolution of antibody fragments. This technique rapidly improved antibody affinity by over 30-fold through targeted mutations in complementarity determining regions (CDRs).
Area of Science:
- Biotechnology
- Molecular Biology
- Immunology
Background:
- Antibody engineering is crucial for developing diagnostics and therapeutics.
- Directed evolution methods are essential for improving antibody affinity and function.
- In vitro display technologies offer powerful platforms for antibody library screening.
Purpose of the Study:
- To demonstrate the utility of in vitro virus mRNA display for antibody fragment evolution.
- To improve the affinity of a single-chain variable fragment (scFv) antibody against fluorescein.
- To identify key mutations responsible for enhanced antibody affinity.
Main Methods:
- Application of in vitro virus mRNA display for antibody evolution.
- Covalent linkage of antibody phenotype to genotype (mRNA) via puromycin.
- Random mutagenesis using error-prone DNA shuffling.
- Off-rate selection for affinity maturation.
- Kinetic analysis and site-directed mutagenesis for validation.
Main Results:
- Achieved affinity maturation of an anti-fluorescein scFv after four rounds of selection.
- Obtained six unique sequences with affinity-matured mutants featuring consensus mutations.
- Demonstrated a decrease in off-rates by over one order of magnitude.
- Improved dissociation constants by approximately 30-fold.
- Identified two critical mutations within complementarity determining regions (CDRs) responsible for affinity enhancement.
Conclusions:
- In vitro virus mRNA display is a powerful tool for rapid, artificial evolution of high-affinity antibodies.
- Optimization of complementarity determining regions (CDRs) is key for enhancing antibody affinity.
- This method holds significant potential for developing advanced diagnostic and therapeutic antibodies.
