A review. In recent years, antibody engineering has become one of the most important and most productive routes to drug discovery. It is now widely accepted that this approach can reduce development times and increase potential success, compared with classical drug development. Until recently, the isolation and production of therapeutic-antibody products has been concentrated on larger, protein targets. A research team at Haptogen has now overcome the significant tech. difficulties that have been associated with raising antibodies to the smallest of small mols. - bioactive haptens - and, for the first time, anti-hapten therapeutics can be realized. Here, we outline our pioneering approach to antibody engineering and present the results of early work in the important field of anti-infective therapy.