B3 Monoclonal antibodies

• Monoclonal antibody

  Has a complementary shape to the unique antigen so it can only attach to ONE type of cell
• Why are they useful?

  Able to target a specific chemical or specific cells in the body (as they can only attach to a specific type of cell)
• Lymphocyte

  White blood cell that makes antibodies
• Myeloma Cell

  Tumour cell that can clone itself quickly
• Hybridoma Cell

  Artificial cell made by fusing a lymphocyte with a myeloma cell. It can make antibodies and divide quickly
• What are the steps of creating a monoclonal antibody?

  Mouse is injected with the antigen

  Mouse lymphocytes make the specific antibody that can attach to the antigen

  Lymphocyte is combined with a myeloma cell

  Hybridoma cell is formed

  The Hybridoma cell is cloned producing many identical cells that make the specific antibody

  Large amounts of antibody are collected and purified
• Uses of monoclonal antibodies

  Diagnosis eg. pregnancy testing

  In labs to measure levels of hormones or detect pathogens in the blood

  Locate and identify specific molecules by attaching fluorescent dye

  Treat diseases eg. cancer by targeting particular drugs
• Pregnancy testing - Reaction Zone

  hCG is found in the urine of pregnant women only

  Monoclonal antibody (with dye attached) attaches to the hCG in the urine and diffuses up the test to the results window
• Pregnancy testing - Results window

  hCG attaches to the monoclonal that is in the results window

  This means the dye is visible resulting in a line in the results window (positive test)
• Pregnancy testing - Control zone

  There is another monoclonal antibody in the control window

  This means that a line will always appear in the control window

  This indicates the test is working
• Locating and identifying cancer cells

  Dye is attached to the monoclonal antibody

  Monoclonal antibody has complimentary shape to the unique tumour markers on cancerous cell

  So the dye only attaches to the cancerous cells
• Targeting cancer cells with radioactive or toxic drugs

  These drugs are specifically targeted to cancerous cells as the monoclonal antibody can only attach to the tumour markers (due to its complementary shape)

  The cancer cell is killed by the drug
• Targeting cancer cells with chemicals that stop growth and division

  Drug stops growth factor (the chemical that causes cells to grow)

  It is attached to the monoclonal antibody which attaches to the tumour markers due to complimentary shape

  so only cancerous cells stop growing
• Problems with monoclonal antibodies

  Side effects