Monoclonal Antibodies

An article about monoclonal antibodies, their production, and applications in medicine.

Monoclonal antibodies (mAbs) are antibodies that are made by identical immune cells that are all clones of a unique parent cell. They have monovalent affinity, in that they bind to the same epitope. Monoclonal antibodies can be produced in the laboratory and are used in various therapeutic, diagnostic, and research applications.

History

The development of monoclonal antibodies began in the 1970s. In 1975, Georges Köhler and César Milstein developed the hybridoma technique, which allowed for the production of large quantities of identical antibodies. This breakthrough earned them the Nobel Prize in Physiology or Medicine in 1984.

Production

Monoclonal antibodies are produced using the hybridoma technology. This involves the fusion of an antibody-producing B cell with a myeloma (cancer) cell. The resulting hybrid cell, or hybridoma, can be cultured to produce large amounts of the desired antibody.

Steps in Production

1. Immunization: An animal, usually a mouse, is immunized with an antigen to elicit an immune response. 2. Cell Fusion: B cells from the spleen of the immunized animal are fused with myeloma cells. 3. Selection: The fused cells are cultured in a selective medium (HAT medium) that allows only hybridomas to survive. 4. Screening: Hybridomas are screened to identify those producing the desired antibody. 5. Cloning: Selected hybridomas are cloned to ensure monoclonality. 6. Production: Cloned hybridomas are cultured to produce monoclonal antibodies in large quantities.

Applications

Monoclonal antibodies have a wide range of applications in medicine, diagnostics, and research.

Therapeutic Uses

Monoclonal antibodies are used in the treatment of various diseases, including:

• Cancer: mAbs can target specific cancer cells, delivering cytotoxic agents or marking them for destruction by the immune system. Examples include rituximab and trastuzumab.
• Autoimmune Diseases: mAbs can modulate the immune system, as seen with infliximab for rheumatoid arthritis.
• Infectious Diseases: mAbs can neutralize pathogens, such as palivizumab for respiratory syncytial virus (RSV).

Diagnostic Uses

Monoclonal antibodies are used in diagnostic tests, such as:

• ELISA: Enzyme-linked immunosorbent assays use mAbs to detect the presence of antigens or antibodies in a sample.
• Immunohistochemistry: mAbs are used to detect specific proteins in tissue samples.

Research Uses

In research, monoclonal antibodies are used to:

• Identify and isolate proteins: mAbs can be used to purify proteins from complex mixtures.
• Study cell signaling: mAbs can block or activate signaling pathways to study their effects.

Advantages and Limitations

Advantages

• Specificity: Monoclonal antibodies are highly specific to their target antigen.
• Reproducibility: Once a hybridoma is established, it can produce consistent batches of antibodies.

Limitations

• Cost: Production of monoclonal antibodies can be expensive.
• Immunogenicity: Some monoclonal antibodies can elicit an immune response in patients.

Also see

• Antibody
• Hybridoma technology
• Immunotherapy
• Biotechnology