Monoclonal Antibodies

Monoclonal antibodies are identical antibodies made by the many descendants (clones) of a single B cell. Because of their unique specificity for different molecules, monoclonal antibodies are promising treatments for a range of diseases. Researchers make monoclonal antibodies by injecting a mouse with a target antigen and then fusing B cells from the mouse with another long-lived cell. The resulting hybrid cell becomes a type of antibody factory, turning out identical copies of antibody molecules specific for the target antigen.

Mouse antibodies are "foreign" to people, however, and might trigger their own immune response when injected into a human. Therefore, researchers have begun to study "humanized" monoclonal antibodies. To construct these molecules, scientists take the antigen-binding portion of a mouse antibody and attach it to a human antibody scaffolding, greatly reducing the foreign portion of the molecule.

Monoclonal Antibody Therapy

Because monoclonal antibodies recognize very specific molecules, they are used in diagnostic tests to identify invading pathogens or changes in the body’s proteins. They can also be used to treat cancer. These antibodies can identify substances on cancer cells or normal substances that may help cancer cells grow. The antibodies attach to the substances and kill the cancer cells, block their growth, or keep them from spreading. Monoclonal antibodies are given by infusion. They may be used alone or to carry drugs, toxins, or radioactive material directly to cancer cells. Monoclonal antibodies are also used in combination with chemotherapy as adjuvant therapy.

Trastuzumab (Herceptin) is a monoclonal antibody that blocks the effects of the growth factor protein HER2, which transmits growth signals to breast cancer cells. About one-fourth of patients with breast cancer have tumors that may be treated with trastuzumab combined with chemotherapy.

Source:

National Cancer Institute, USA.