3.2 Monoclonal Antibodies

These flashcards cover specification point 4.3.2 Monoclonal Antibodies (Biology Only) in Topic 3 - Infection & Response for AQA GCSE Biology. This includes: 4.3.2.1 Producing Monoclonal Antibodies and 4.3.2.2 Uses of Monoclonal Antibodies.

What are monoclonal antibodies produced from?

Single clone of cells

How are monoclonal antibodies able to target a specific chemical or specific cells in the body?

Antibodies specific to one binding site on one protein antigen

Fully explain the process of producing monoclonal antibodies.

• Stimulating mouse lymphocytes — makes particular antibody

• Lymphocytes + tumour cell → hybridoma

• Hybridoma can:

  • divide rapidly

  • make antibody

• Single hybridoma cells cloned — produces many identical cells → all produce same antibody

• Large amount of antibody collected and purified

Why are tumour cells used when making monoclonal antibodies?

Divides rapidly

What are four uses of monoclonal antibodies?

• Diagnosis — e.g. pregnancy tests

• Measure levels of hormones and chemicals in blood or detect pathogens

• Locate or identify specific molecules in cell/tissue — binding them with fluorescent dye

• Treat diseases — e.g. cancer

Explain how a pregnancy test works — in relation to monoclonal antibodies.

hCG hormone in pregnant women’s urine

• Two sections of stick

  • First section — mobile antibodies complementary to hCG hormone — attached to blue beads

  • Second section — stationary antibodies complementary to hCG hormone — stuck down to stick

• Individual urinates on first section

  • hCG is present = binds to mobile antibodies — forms hCG complexes

• Carried in flow of liquid to second section

• Stationary antibodies bind to hCG complexes

• Blue dye appears in both control and results zones — shows positive result

Explain how monoclonal antibodies can be used in research to find or identify certain molecules on a cell or tissue.

• The monoclonal antibodies are modified so that they will bind to the molecule you are looking for.

• The antibodies are also bound to a fluorescent dye.

• If the molecules are in the sample then the antibodies bind to it, and the dye can be observed.

Explain how monoclonal antibodies could be used to treat cancer.

• The monoclonal antibody can be bound to a radioactive substance, a toxic drug or a chemical which stops cells growing and dividing.

• It delivers the substance to the cancer cells without harming other cells in the body.

What are the advantages of using monoclonal antibodies? (3)

• They only bind to specific cells, meaning healthy cells are not affected.

• They can be engineered to treat many different conditions.

• They can be produced quickly.

What are the disadvantages of using monoclonal antibodies? (3)

• Expensive to develop

• Difficult to attach monoclonal antibodies to drugs

• As they were produced from mice lymphocytes, they often triggered an immune response when used in humans.

Figure 1 shows a test strip that can detect the presence of an anabolic steroid in an athlete’s urine.

• The end of the test strip is dipped in urine.

• The urine moves up through the test strip.

• The test area and the control area contain a dye.

• The dye turns blue when monoclonal antibodies bind to it.

Suggest the purpose of the control area in the test strip. [1 mark]

To show that the test is working.

• A monoclonal antibody has been produced to treat pancreatic cancer.

Explain how the monoclonal antibody works to treat pancreatic cancer. [3 marks]

• Monoclonal antibody attached to chemical

• Will only target antigen on tumour

• So chemical binds to cancer cells → stops them dividing