Surface display technologies are powerful tools for high-throughput screening in antibody discovery and optimization. Phage display and yeast display are commonly used for displaying and screening the library of antibody fragment such as single-chain variable fragment (ScFv). However, for pharmaceutical development, scFv requires conversion into full-length glycosylated IgG for further characterization. The converted full-length IgG may lose activity and often require further affinity maturation. The selected scFv fragment may be difficult to re-engineer and to generate full-length IgG which has good expression and biophysical properties required for pharmaceutical development. Mammalian cells are idea system to display full-length IgG in native form and allow selection of antibody for functional properties. However, mammalian cell display system has some disadvantages, such as small library size, difficulty in genetic manipulation, slow generation time, and high cost. Mammalian cell display system is not an efficient system for antibody maturation.
Like mammalian cell expression system, glycoengineered P. pastoris cells contain eukaryotic internal quality control apparatus for antibody correct folding and post-translational modification (such as human-like N-glycosylation). We have applied glycoengineered P. pastoris expression system to develop a platform of full-length IgG pichia display. This advanced platform can combine the advantages of both yeast and mammalian cell display into one system. It can be employed for antibody humanization, selection and maturation in native IgG format. The selected antibody can be used directly for animal study and clinical trial.
Based on our proprietary platform of full-length IgG pichia display, we can provide one-stop services for antibody humanization, affinity maturation, and antibody production.
Advantages of Full-length IgG Pichia Display
1. In glycoengineered P. pastoris, full-length IgG is displayed as close to native form in molecular structure, biophysical property, and biological function. ScFv in phage or yeast display requires format conversion into full-length IgG, which may lose activity.
2. Comparing to the mammalian cell display, full-length IgG pichia display has many advantages，such as large library size, easy genetic manipulation, fast generation time, and low cost screening.
3. FACS sorting of full-length IgG pichia display system is based on both antibody affinity and display level. It can eliminate the deviation caused by expression levels and distinguish clones with small affinity. However, phage display screen is usually adversely affected not only by affinity, but also by the expression level.
4. FACS sorting technology can directly select high, medium, and low affinity clones at a time.
5. By using FACS with double staining, antibody affinity can be directly determined on the surface of cells. There is no need of time-consuming subcloning, expression and purification.
