Large libraries can be generated and screened to identify high-affinity monoclonal antibodies for target antigens using phage antibody display. However, while one of the advantages of the phage display method is library size and diversity, there is limited ability to quantitatively enrich for specific binding properties such as affinity. One efficient way of overcoming this limitation is to combine the scale of phage display selections with the flexibility and quantitativeness of FACS-based yeast surface display selections. Creative Biolabs offers the phage and yeast display combination services to identify human monoclonal antibodies, which has been widely used for the identification of monoclonal antibodies with specific binding properties.
Phage Antibody Display to Develop Monoclonal Antibodies
Phage antibody display libraries are widely used to develop monoclonal antibodies with high affinity for target antigens, and purified recombinant protein antigens and living cells are commonly used as the selection targets for phage antibody display libraries. Although very large libraries can be generated and screened in phage antibody display-based selections, it is difficult to fine-tune the selections to select for specific binding properties such as affinity. In addition, while a selection of phage antibody display libraries on living cells yields antibodies that bind to native epitopes on the cell surface, it is difficult to direct the selections towards a specific target.
Yeast Surface Display for Antibody Screening
Yeast surface display has been widely utilized to screen large libraries for proteins or protein fragments with specific binding properties, and protocols for the construction and application of yeast surface display libraries have been previously described. Using labeled target antigens, yeast antibody display libraries can be coupled with FACS to select high-affinity antibodies that bind specifically to the targeted antigen. Utilization of yeast antibody display combined with FACS allows a more controlled and quantitative selection process that can be fine-tuned to enrich clones with particular binding properties more effectively than phage display.
Combining Phage and Yeast Cell Surface Antibody Display to Identify Human Monoclonal Antibodies
To generate yeast antibody display libraries from pre-enriched phage antibody display outputs selected on recombinant antigens, live cells, or tissues has proven to be an efficient way to address these limitations.
Fig 1. Outline of the combination selection strategy utilizing both phage and yeast surface antibody display. Naive phage antibody display libraries will be first selected on target antigens or ligands, live or fixed cells, or tissues (fresh, frozen, or formalin-fixed paraffin-embedded). Selection condition can be manipulated to enrich for desired antibody property such as internalization. Following two to three rounds of selection, plasmid DNA from the polyclonal phage output will be purified and used as template to amplify the scFv genes with flanking primers designed for gap-repair-based yeast transformation. The resulting yeast antibody display libraries will be subjected to FACS-based selection against fluorescence-labeled antigens or ligands to identify high-affinity binders (Bidlingmaier et al., 2015).
At Creative Biolabs, our scientists have established an effective way to generate yeast human monoclonal antibodies display libraries by homologous recombination gap repair cloning using pre-enriched phage antibody display selection outputs as starting material, FACS-based enrichment of target antigen-binding clones from these libraries, and screening and sequencing analysis.
If you are interested in learning more about Creative Biolabs’ yeast display services, please contact us for more details.