Fig. 4.
Construction and affinity selection with phage-display antibody library. a Outline of the procedure for constructing a phage-displayed antibody (Fab or scFv) library. b Structure of IgG molecule. Fab consists of the light chain and the first two domains of the heavy chain. scFv is composed of the variable heavy (VH) and variable light (VL) domains joined by a short flexible polypeptide linker. c Biopanning with a phage-displayed library. Initial pools of antibodies on the surface of phages are applied to antigens immobilized on a solid surface, e.g., ELISA plates or magnetic beads. Non-specific phages are removed by stringent washing. Antigen-bound phages are eluted and re-infected into E. coli to produce a subset of phages for the next cycle of panning. After several rounds, the antigen-binding clones are sufficiently enriched and individual clones can be selected for further analysis