Uses of Monoclonal Antibodies (Cambridge (CIE) AS Biology): Revision Note

Use of monoclonal antibodies

Diagnostic uses of monoclonal antibodies

• Monoclonal antibodies can be used diagnostically for:

  • Diagnosing HIV

  • Detecting the presence of pathogens such as Streptococcus bacteria

  • Distinguishing between Herpes I and Herpes II virus

  • Detecting cancer cells

• Monoclonal antibodies can also be used to locate the position of blood clots for patients thought to have deep vein thrombosis

• This occurs by:

  • Injecting a mouse with human fibrin (the main protein found in blood clots)

  • This activates the plasma cells to produce antibodies against fibrin

  • These cells are collected from the mouse spleen

  • The plasma cells are then fused with tumour cells forming hybridomas that produce antifibrin antibodies

  • To detect where the antibodies are binding to fibrin molecules, a radioactive chemical (producing gamma radiation) is attached to the antibodies making them radioactively labelled

  • A gamma-ray camera is used to detect where these radioactively labelled antibodies have attached to a fibrin molecule, hence indicating where blood clots can be found

• Generally monoclonal antibodies are used only once

Therapeutic uses of monoclonal antibodies

• Therapeutically, monoclonal antibodies have multiple applications to include:

  • Treatment for the rabies virus, which can be potentially fatal

    • This is done by injecting purified antibodies

  • The prevention of transplanted organ rejection

    • This is done by intervening with the T-cells involved in the rejection process

  • Autoimmune therapies for allergic asthma and rheumatoid arthritis

    • Monoclonal antibodies are able to bind and deactivate factors involved in the inflammatory response

  • Treatment for diseases caused by the overproduction or inappropriate production of B-cells (e.g. leukaemia, multiple sclerosis and myasthenia gravis)

    • The antibody (rituximab) binds to cell surface receptor proteins on B-cells (not plasma cells) and causes the death of the cells

  • Prevention of blood clotting following angioplasty procedures

    • Monoclonal antibodies bind to receptors on the platelet surface thereby inhibiting fibrinogen from binding and subsequent clotting from ensuing

  • Targeted treatment of breast cancer

    • Herceptin is a monoclonal antibody used to treat breast cancer

    • It recognises receptor proteins on the surface of cancer cells and binds to them allowing the immune system to identify and destroy them

  • Treatment of melanoma (a type of skin cancer)

    • The antibody (ipilimumab) binds to a protein produced by T-cells (whose role is to reduce the immune response)

    • This results in the immune system remaining active against the cancer cells