Recombinant targeted proteins for biotherapy.

In an effort to improve existing biotherapies, researchers have used recombinant techniques to alter the structure of toxins, monoclonal antibodies, and other receptor and effector molecules. Experimental research has demonstrated that the extent of problems such as nonspecific toxicity and rapid clearance by the immune system are not as great with genetically engineered toxins as opposed to native toxins. Fusion proteins, which combine portions of toxins, antibodies, or various effector molecules, exhibit the preferred biologic properties of their constituents. Unlike their murine counterparts, chimeric antibodies have the ability to invoke cell-mediated immunity and are less immunogenic to humans. Because they display different antigen-binding specificities on the same molecule, hybrid hybridomas are a potential means of juxtaposing effector cells or toxins to tumor cells. These and other positive features of recombinant proteins offer a decided advantage over previous biotherapeutic agents, and these molecules are expected to find application in the treatment of cancer, the acquired immunodeficiency syndrome, and autoimmune diseases.