monoclonal antibodies

• what is an antibody?

  an antibody is a protein which has a specific binding site this is complementary in shape to a specific antigen.
• antibody structure?

  • antigen binding site
  • disulfide bridges
  • heavy chain
  • light chain
  • variable region
  • constant region

  
• what are monoclonal antibody?

  • antibodies made from the same plasma cell (B- cell)
• what is the distinguishing feature of monoclonal antibodies?

  they all have the same tertiary structure and therefore bind to one specific antigen.
• how can monoclonal antibodies be used directly for medical treatment?

  monoclonal antibodies - made in labs

  e.g. cancer

  • cancer can be treated using monoclonal antibodies which have a complementary binding site in shape to the antigen present of the surface of cancer cells
  • these specific antibodies will ONLY bind to cancer cells and prevent growth and limit mitosis
  • they do not harm other normal body cells
• how are monoclonal antibodies used for indirect medical treatment?


  these monoclonal antibodies are complementary in shape to the antigens on the surface, however also have a drug attached to them (antibodies)

  e.g. cancer cells - "bullet drugs" - direct to the site needed

  • these drugs are attached to monoclonal antibodies that are specific for antigens on cancer cells only, forming an antigen - antibody complex.
  • antibodies will bind ONLY to cancer cells and target them for destruction
• how are monoclonal antibodies used in medical diagnosis?

  test for: pregnancy, LFT

  • can be used to test someone's body fluids to see if they have a specific infection
• how can monoclonal antibodies be used to test if a person is pregnant or not/ LFT's? (if they have a specific substance)

  1. mobile antibodies - complementary in shape to the hormone (hcG), coloured dye attached
  2. Test strip: second antibody - immobilised , complementary to the antigen
  3. control strip: immobile antibody, specific for first moving antibody (mobile antibody)
• how are monoclonal antibodies made?

  • can be made by injecting an animal (e.g. mice) with a specific antigen
  • antigen doesn't have to be a pathogen (any non-self molecule)
  • then animal produces antibodies via immune system
  • extracted & purified
• issues around using monoclonal antibodies?

  animal testing - side effects from injection or antigen

  method of production - uses tumour cells from mice that have deliberately been given cancer

  human testing - death/harmful side effects occurred in drug trials
• what makes antibodies highly specific?

  antibodies are very specific because they have complementary shapes to antigens.