Single-chain antibody variable fragment (scFv) is widely used at screening stage. However, the scFv format often proves to be inefficient in downstream stages such as crystallization and in vivo applications. Conversion of a scFv format to other ones such as a fragment antigen binding (Fab), a scFv-fragment crystallizable region (scFv-Fc), a scFv-constant heavy chain (scFv-CH) and an immunoglobulin (IgG) formats can be cumbersome due to different sets of restriction enzyme sites in multiple vectors. To facilitate antibody format conversion in laboratory settings, we developed a cloning platform, called “AbVec”, with the common restriction enzyme sites across various forms of vectors. In the AbVec platform, a scFv clone selected from phage display is modularized into VH and VL regions and transferred to vectors for Fab, scFv-Fc, scFv-CH and IgG production using the same restriction enzyme sites. Using scFv F9, specifically recognizing a pneumococcal secreted peptide, we demonstrated the AbVec platform yielded the expression vectors within a week. Different formats of the antibodies were successfully expressed and purified homogenously, supporting the usefulness of the AbVec platform. The AbVec platform will facilitate otherwise time-consuming conversion process in laboratory settings.
INTRODUCTION
RESULTS AND DISCUSSION
METHODS