L8 - Monoclonal Antibodies

• How to make monoclonal antibodies:

  1. An antigen is injected into a mouse
  2. The mouse naturally produces lymphocytes, which produce antibodies specific to the antigen
  3. Spleen cells which produce B-lymphocytes are removed during a small operation
  4. The B-lymphocytes are fused with human cancerous white blood cells called myeloma cells to form hybridoma cells which divide indefinitely
  5. These hybridoma cells divide and produce millions of monoclonal antibodies specific to the original antigen
• Use of monoclonal antibodies:

  • Diagnosing chlamydia and HIV using fluorescence (more fluorescence more infection)
  • Tissue typing for transplants
  • Monitoring spread of malaria (MCAs detect Plasmodium pathogen so success of malarial drugs can be tested)
  • Supporting chemotherapy - MCAs produced against tumour markers, MCAs can then deliver anti-cancer drugs directly to these cancer cells
• Monoclonal antibodies have anti-cancer drugs attached to them
• Tumour marker

  Antigen only found on tumour cells
• Monoclonal antibodies are specific so won’t attach to any other antigen
• Diagnosis of diseases including Chlamydia and HIV

  Immunoassays are used - labelled (via radioactivity or fluorescence) monoclonal antibodies are added to test samples of infected body fluids and attach to specific antigens. The extent of the infection is related to the extent of the labelling
• Tissue typing for transplants

  The concentration of non-self antigens in tissues is assessed. Monoclonal antibodies can be used against helper T-cells (T-lymphocytes) so B-lymphocytes, normally causing rejection, are prevented from functioning
• Monitoring the spread of malaria

  Blood is taken from samples of people (even if they do not show any malarial symptoms) and tested with labelled monoclonal antibodies. Monoclonal antibodies will detect the presence of Plasmodium in the bloodstream (even if they are dead - killed by antimalarial drugs) as they have specific antigens and will attach to the labelled monoclonal antibodies. This enables the success of anti-malarial drugs and the potential spread of malaria to be monitored
• Supporting chemotherapy for cancers

  The destruction of cancer cells can be targeted with the use of monoclonal antibodies. Some types of cancer cells have specific antigens called tumour markers. Monoclonal antibodies can be produced that act against tumour markers. If these are attached to anti-cancer drugs, they will deliver the drug directly to the cancer cells