Biologicals: principles, techniques and mechanisms of action

Biological agents for the treatment of IBD are the result of both the explosion of knowledge precipitated by the techniques of molecular biology, and by the ability to use these same techniques to produce agents. Thus, there has been a greatly facilitated translation of basic knowledge into clinical therapy. An astounding number of biologic agents are currently in development for the treatment of IBD and other immune-mediated conditions. These include native microbiologic preparations isolated for beneficial properties, recombinant cytokines and anticytokines, monoclonal antibodies, antisense oligonucleotides, and in the future, somatic gene therapy. This work seeks to describe the principles and techniques of biologic agent development, as well as prime sites of action targeted by these agents. Recent advances in the techniques of molecular biology have made possible unprecedented progress in the treatment of many conditions. The techniques of molecular biology have provided new methods of drug discovery and at the same time have elucidated new therapeutic targets. Most notable has been the progress made in the treatment of chronic inflammatory and immune mediated conditions, including inflammatory bowel disease. This paper is intended to highlight the methodological principles behind biologic agents, methods of discovery and production, and to highlight potential therapeutic targets for these new agents.