As part of Abcore’s antibody discovery platform, once a library is built we need to enrich the phages to the target of interest. During multiple rounds of panning, we develop enriched phage pools which are enriched for phages expressing the nanobodies that bind to the target of interest. We normally do 3 rounds of panning and find unique positive binders in the phage pools from round 2 and round 3.
Abcore is able to pan antibody libraries (either immunized or naïve) in 4 different ways:
- Solid phase
- Live cell
Solid Phase Panning: In this phage display panning method, the target of interest is bound to high-bind plastic plates. It can bind in any orientation, and the target may or may not be in a physiologically active conformation.
Semi-Solution Panning: This panning method requires your target to be biotinylated. The target of interest is bound to streptavidin plates for panning. Depending on the biotinylation method, the target can either be oriented or bound in any orientation and may help in preserving functionality of the target.
Solution Panning: Abcore performs true solution panning with biotinylated targets. The biotinylated target is incubated with streptavidin magnetic beads and pulled down with a magnetic. Similar to semi-solution panning, and depending on the biotinylation method, this panning method allows for there to be no steric hindrance with the target, and to more likely be more physiological.
Live Cell Panning: Abcore has pioneered panning using live cells. This cutting-edge panning method allows us to pan using target protein that is closest to physiologically active. Proteins are likely folded and post-translationally modified as they are physiologically, which is best for many pharmacological applications.
Often times we use a strategy of negative or positive pre-panning steps to address the cross-reactivity goals of the project. This can involve a close isoform or a parental cell line to remove any non-specific binders.