Recombinant antibody fragments.

Recombinant antibodies and their fragments now represent over 30% of all biological proteins undergoing clinical trials, which recently culminated in FDA approval for the first engineered cancer therapeutic antibody. Other successful applications include both the effective enhancement of the human immune response for cancer therapy and the reduction of unwanted immune rejections following transplantation and antibody therapy. Important advances have been made in the methods for design, selection and production of these new types of engineered antibodies. Innovative selection methods have enabled the isolation of catalytic antibodies and high-affinity viral-specific antibodies, the latter capable of redirecting viruses for gene therapy applications. In numerous practical applications, recombinant antibody fragments have been fused to radioisotopes, drugs, toxins, enzymes and biosensor surfaces.