Antibody engineering: advances from the use of Escherichia coli expression systems.

Synthesis in Escherichia coli of correctly folded antibody fragments that bind antigen with the same affinity as the whole antibody is now possible. Here I review the techniques for achieving this and the physical properties of the various fragments produced. This technology not only facilitates antibody engineering but is also the basis of screening libraries for binding activity. Although the immunization of animals has not been made unnecessary in the production of monoclonal antibodies, steps toward this goal are now feasible.