Intrabodies: Turning the immune system inside out for new discovery tools and therapeutics

Extract: The human immune system has evolved over millennia to effectively deal with a huge diversity of threats to the integrity of the body. Antibodies, which are the principal agents of the humoral immune system, are masterpieces of evolutionary engineering, combining precise discrimination of target molecules or structures with potent binding capacities. The function of an alien molecule can either be blocked directly by an antibody binding it, or the antibody can recruit effector functions from the immune system to bring about the neutralization, destruction, or removal of the molecule. The potential value of antibodies is nowhere more evident than in the production of new medicines. Technological developments have allowed for the isolation and large scale production of single antibody molecules that can target disease-relevant molecules or structures either in the body fluids or on the surface of cells, resulting in highly precise and potent therapeutic outcomes and, as a result, antibodies currently form the fastest growing group of new drugs being developed and brought to market.