Approach for construction of a completely synthetic human antibody library from well--expressed framework

A new and feasible approach is described for construction of a completely synthetic human single-chain Fv antibody library based on well-expressed framework. The library was constructed by appending partially randomized CDR3 regions onto two antibody germ line segments most frequently found in human antibodies with good expression behavior. The framework was fully synthesized and the CDR3 were designed partially randomized according to the natural antibody sequences. A novel split-mix-split method was adopted to synthesize the CDR3 sequences. The sequencing and expression analysis of the unselected libraries indicated that the frequency of correct and functional antibodies was 88%. This approach provides a simple and feasible model for construction of single-framework and multi-framework antibody library.