Phage display

Definition

Phage display is a laboratory platform that allows scientists to study protein interactions on a large-scale and select proteins with the highest affinity for specific targets.

The photograph shows a phage as seen under a microscope. Credit: Ian Hands-Portman.

Importance

The key advantage of phage display is that it provides a means to identify target-binding proteins from a library of millions of different proteins without the need to screen each molecule individually. This makes it possible to screen billions of proteins each week. By linking a selected protein with its encoding gene, phage display also provides a means to easily identify coding sequences of binding proteins. These can be stored, amplified or processed in other ways. Phage display is a pivotal tool for early basic scientific research and for the development of new drugs and vaccines. The technology has proved particularly important to the production of safer and more effective monoclonal antibody drugs. Phage display libraries consisting entirely of human antibody sequences, for example, have made it possible to produce fully human antibodies. The first fully human therapeutic antibody (adalimumab), a blockbuster drug, generated US$9.3 billion in annual sales in 2012. Four fully human therapeutic antibodies currently approved as treatments in the US and the UK were developed using phage display and many more are in the pipeline. Phage display is also used to develop vaccines for conditions such as prostate cancer and HIV. It is also an important tool for the generation of diagnostic tests for monitoring disease progression and evaluating treatment efficacy.

Discovery

Phage display was first described by George P Smith in 1985, who deployed it as a method to identify a gene against which he had raised antibodies. The technique was taken further by Greg Winter and John McCafferty at the Laboratory of Molecular Biology in Cambridge, UK, and Richard Lerner and Carlos F. Barbas at The Scripps Research institute, US, who independently used phage display to build large libraries of fully human antibody sequences. This work laid the foundation for the development of human antibody based drugs. Today there are several types of phage display libraries, including peptide libraries, protein libraries and antibody libraries.

Application

The phage display technique relies on the generation of a library of millions of bacteriophages that have been genetically engineered to display different peptides or proteins on their surface. This is achieved by inserting a gene encoding a protein of interest into the phage's protein shell, which sets up a direct physical link between DNA sequences and their encoding proteins. The aim of the modification is to generate a molecule that can mimic a natural modulator within the cellular process. Several types of phages are used for the purpose of phage display. Filamentous bacteriophages are the most popular.

The genetically modified phages are assembled into a library for use as a platform to screen proteins, peptides and DNA sequences. Screening is performed by the addition of the phage-display library to the wells of a microtiter plate that contains immobilised target proteins or DNA sequences. The plate is then incubated for some time to allow the phages to bind with the target of interest and then washed so as to flush away any non-binding phages. Any phages that remain attached to the wells are then removed and inserted into other bacteria for replication. The cycle is repeated until only phage-displaying proteins highly specific for the target remain. Once the whole process is completed, the gene coding for the specific protein is isolated and purified from the phage so that it can be used for different applications.

Any laboratory that is well versed in basic microbiology can easily make a phage display library with minimum expense. This has allowed phages to become an invaluable tool for basic immunological and cellular biological research as well as for the development of new drugs and vaccines. Prior to the development of phage display, drug development depended on the time-consuming and expensive process of combing through hundreds of thousands of components using tests conducted in test tubes or laboratory dishes.

This section was put together by Lara Marks with Gavin Hubbard.

Phage display: timeline of key events

Term 'bacteriophage, was coined by Felix d'Herelle in 1917. 1815-01-01T00:00:00+0000Lederberg was a major pioneer of bacterial genetics. She discovered the lambda phage and invented the replica plating technique. 1922-12-18T00:00:00+0000H. Ruska, 'Uber die Sichtbarmachung der bakteriophagen Lyse im Ubermikroskop', Naturwissenschaften, 28 (1940), 45–6; E. Pfankuch, GA Kausche, 'Isolierung und übermikroskopische Abbildung eines Bakteriophagen', Naturwissenschaften, 28 (1940), 46.1940-01-01T00:00:00+0000The American scientist George Smith develops a method using bacteriophages for studying protein-protein, protein-peptide and protein-DNA interaction. Today phage display is a major tool for drug discovery.1985-01-01T00:00:00+0000Gregory Winter together with David Chiswell set up CAT to develop phage display technology for monoclonal antibodies1989-01-01T00:00:00+0000Gregory Winter together with CAT create the first phage monoclonal antibodies, laying the foundation for the generation of diverse libraries of randomly shaped human antibodies. With this scientists are no longer dependent on the natural immune system of animals or humans and the limitations this poses for the production of monoclonal antibodies. 1990-01-01T00:00:00+0000This is achieved by Richard Lerner and Carlos Barbas at the Scripps Research Institute with the backing of Stratagene, an American biotechnology specialising in antibody engineering.1991-01-01T00:00:00+0000Adalimumab (Humira) approved by the FDA for the treatment of rheumatoid arthritis. The drug was developed and marketed by a collaboration between Cambridge Antibogy Technology, BASF Bioresearch Corporation and Abbott Laboratories.2002-12-31T00:00:00+0000Lederberg was a major pioneer of bacterial genetics. She discovered the lambda phage and invented the replica plating technique. 2006-11-11T00:00:00+0000
Date Event People Places
1815Discovery of bacteriophages, type of virus that attacks bacteria, by English bacteriologist William TwortTwortUniversity of London
18 Dec 1922Esther Lederberg was born in Bronx, New York, USALederbergWisconsin University
1940First electron microscope pictures of bacteriophages publishedRuska 
1985Phage display method is developed for selecting peptides, proteins or antibodies from a wide number of variants.SmithUniversity of Missouri
1989Cambridge Antibody Technology (CAT) foundedWinter, ChiswellLaboratory of Molecular Biology, CAT
1990Phage display monoclonal antibodies createdWinterLaboratory of Molecular Biology, CAT
1991First display and selection of human antibodies phageBarbas, LernerScripps Research Institute
December 2002First monoclonal antibody made using phage display approved for marketCAT, BASF, Abbott
11 Nov 2006Esther Lederberg diedLederbergWisconsin University

1815

Discovery of bacteriophages, type of virus that attacks bacteria, by English bacteriologist William Twort

18 Dec 1922

Esther Lederberg was born in Bronx, New York, USA

1940

First electron microscope pictures of bacteriophages published

1985

Phage display method is developed for selecting peptides, proteins or antibodies from a wide number of variants.

1989

Cambridge Antibody Technology (CAT) founded

1990

Phage display monoclonal antibodies created

1991

First display and selection of human antibodies phage

Dec 2002

First monoclonal antibody made using phage display approved for market

11 Nov 2006

Esther Lederberg died