What is a Monoclonal Antibody?

Question: What is a Monoclonal Antibody?

What is a monoclonal antibody? How do monoclonal antibodies work as a treatment for rheumatoid arthritis? Which of the biologic drugs are monoclonal antibodies? Are more in development?

Answer: Antibodies are proteins that are generated by the immune system, specifically the white blood cells. They circulate in the blood and attach to foreign proteins called antigens in order to destroy or neutralize them. For example, when you are exposed to a virus, your body will produce antibodies to help rid your system of the infection.

Monoclonal antibodies are laboratory produced substances that can locate and bind to specific molecules such as tumor necrosis factor (TNF), a protein involved in causing the inflammation and damage of rheumatoid arthritis. Two out of the three TNF inhibitors are monoclonal proteins.

Producing man made proteins is an intricate process that involves placing cells in large stainless steel vats filled with nutrients to produce the specified protein. It is extensively tested to ensure purity before it is ready for patient use.

The newest monoclonal protein to be approved for the treatment of rheumatoid arthritis is Rituxan. Like Remicade, it is a chimeric mouse/human monoclinal antibody that is given by intravenous infusion. Unlike Remicade, it attacks the B cells as opposed to TNF. Several new monoclonal antibodies are in the development stage to treat rheumatoid arthritis and other conditions.

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Answers provided by Scott J. Zashin, M.D., clinical assistant professor at University of Texas Southwestern Medical School, Division of Rheumatology, in Dallas, Texas. Dr. Zashin is also an attending physician at Presbyterian Hospitals of Dallas and Plano. He is a fellow of the American College of Physicians and the American College of Rheumatology and a member of the American Medical Association. Dr. Zashin is author of Arthritis Without Pain - The Miracle Of Anti-TNF Blockers. The book is useful for anyone on one of the biologic drugs (Enbrel, Remicade, Humira) or considering the biologic drugs. Read my review of the book.