Phage Display

Phage display technology is based on the linkage between phenotype and genotype and on the replicative capacity of filamentous bacteriophage. Foreign DNA fragments can be inserted into filamentous phage genes coding for phage coat protein to create a fusion protein that is displayed in the phage surface. Billions of antibody fragment (Fab or scFv) sequences can be displayed on phage and presented to different type of proteins in various possible conformations to select specific monoclonal antibodies (mAbs), as shown by pioneer and co-inventor John McCafferty. Due to the flexibility of the phage display-based selection process, this technology enables the identification of monoclonal antibodies with very specific characteristics, representing an alternative to the classical hybridoma technology.

Features that differentiate phage display as an efficient technology for the isolation of mAb

Feature

Description

High throughput Entire library
Selection for function Possibility of selecting antagonistic, agonistic, internalizing antibodies, etc.
Broad range of epitopes Different strategies available to select for epitope specificity (high diversity)
Selection for affinity Selection of monomeric and monovalent displayed Fab libraries on low concentration of antigen in solution drives the isolation of antibodies with higher affinity/potency
Selection for stability Opportunity to isolate stability improved antibody variants by selecting at stringent conditions (phage is extremely stable)

Selection for native conformation

Selections on cells with low copy numbers of receptors is possible

Well established technology for therapeutic antibodies

Humira (anti-TNFα from Abbott / CAT) and Lucentis (anti-VEGF from Genentech), clinical products in the market, obtained via phage display