A two-phagemid system for the creation of non-phage displayed antibody libraries approaching one trillion members

We have designed a two-phagemid system for the construction of very large non-phage displayed Fab antibody libraries in E. coli approaching 10(12) members. The system can accommodate both periplasmic and cytoplasmic Fab expression and should prove useful for the direct selection of functional antibodies by genetic techniques. We successfully alleviate problems of Fab vector instability and report a set of improved 5' primers for the amplification of mouse Ig V(H)95% of mouse Ig V(H) genes and minimize the amount of N-terminal amino acid changes while maintaining the flexibility of periplasmic or cytoplasmic antibody expression in E. coli.