Monoclonal Antibodies

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Monoclonal Antibodies
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• Antibodies have important uses beyond fighting
  infections in the body.
• Production of long-lasting monoclonal antibodies
  is a recent invention and it is used in both
  medicine and research.
• Monoclonal Antibody a stable antibody which can
  be used over a period of time

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Producing Monoclonal Antibodies

• Inject a mouse with a specific antigen to
  stimulate its immune system to produce necessary
  antibodies.
• Extract mouse spleen cells (containing
  B-lymphocytes) and culture them in the lab.
• Extract mouse tumour cells, which grow
  continuously, and culture them in the lab.
• Mix spleen cells and tumour cells on the same
  plate and culture.

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Producing Monoclonal Antibodies

1. Add polyethylene glycol this causes some
   B-lymphocytes to fuse with tumour cells to
   produce a hybrid cell called a hybridoma.
2. Grow the cells under conditions that allow only
   hybridoma cells to survive.
3. Extract the cells, culture them separately and
   test the medium around each cell for the specific
   antibody of interest.
4. Culture the cells making the desired antibody and
   use as needed.

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http//youtu.be/7ymKofaHCoY
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Pregnancy Tests

• A pregnant woman has the hormone human chorionic
  gonadotrophin (HCG) in her urine.
• Monoclonal antibodies to HCG have been produced.
  These have been attached to enzymes which can
  later interact with a dye molecule and produce a
  colour change.

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Pregnancy Tests

• Pregnancy test contains three regions reaction
  region, test region and control region
• Reaction region contains monoclonal anti-HCG
  antibodies linked to enzyme
• Test region contains polyclonal anti-HCG
  antibodies, which will bind to HCG molecules
  bound to monoclonal anti-HCG antibodies. Also
  contains dye molecules which will be activated if
  monoclonal antibodies bind to polyclonal anti-HCG
  antibodies
• Control region contains anti-mouse antibodies
  and dye molecules which will be activated if
  monoclonal antibodies bind here

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Pregnancy Tests

• When pregnant womans urine travels up the
  pregnancy test, HCG will bind to monoclonal
  antibodies in reaction region
• Movement of the urine will move the monoclonal
  antibodies up to the test region
• Monoclonal antibodies with bound HCG will bind to
  antibodies in test region and activate dye
  molecules, producing a colour change
• Any unbound monoclonal antibodies will continue
  to travel to control region and will bind to
  anti-mouse antibodies, activating dye molecules
  and producing a colour change

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Pregnancy Tests
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Diagnosis of HIV Infection

• The test of HIV infection is based on detecting
  the presence of HIV antibody in the patients
  blood serum.

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1. HIV antigen is attached to the plate.
2. Patients serum passed over the plate. Any HIV
   antibody in the patients serum will attached to
   the antigen already on the plate.
3. A second antibody which is specific to the HIV
   antibody is passed over the plate. This antibody
   will attach to the concentrated HIV antibody on
   the plate. This second antibody has an enzyme
   attached to its structure.
4. Chromagen dye is passed over the complex of
   concentrated HIV antibody/conjugated antibody.
5. The enzyme will turn the chromagen to a more
   intense colour. The more intense the colour, the
   greater the HIV antibody level. This would be the
   a positive result for a HIV test.

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Treatment of Cancer

• Cancer cells carry specific tumour-associated
  antigens (TAA) on their plasma membrane.
• Monoclonal anti-TAA antibodies have been
  produced.
• Drugs which kill tumour cells or inhibit key
  proteins in tumour cells are attached to
  monoclonal anti-TAA antibodies.
• Cancer cells are specifically targeted, avoiding
  damage to healthy host cells.

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Problems

• Many patients develop immune response to
  monoclonal antibodies produced in mice, as these
  are foreign proteins.
• Genetically engineered antibodies are being
  perfected to avoid triggering immune response.