Monoclonal antibodies (mAbs) represent the largest class of recombinant proteins used in modern medicine. These proteins are designed to bind to specific antigens, such as those found on the surface of cancer cells or pro-inflammatory cytokines in autoimmune diseases. rDNA technology allows for the "humanization" of these antibodies—initially derived from mice—by replacing the murine protein segments with human sequences to prevent the patient's immune system from rejecting the drug.

The production of mAbs involves complex recombinant workflows where both the "heavy" and "light" chains of the antibody are co-expressed in a single host cell. The resulting proteins are then purified through a series of chromatography steps to ensure they are free from host cell proteins and DNA. Technical data regarding the downstream processing and characterization of these biologics can be found in the Recombinant DNA Technology Market industry outlook. These targeted therapies have revolutionized the treatment of oncology, rheumatology, and gastroenterology.

Future trends in antibody engineering include the development of "bispecific" antibodies, which can bind to two different targets simultaneously (e.g., a tumor cell and a T-cell), and "antibody-drug conjugates" (ADCs), where a potent toxin is chemically linked to a recombinant antibody. These innovations rely on the precise genetic control provided by rDNA technology to create complex, multi-functional molecules that can deliver highly localized therapy while minimizing systemic side effects.