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?

A single clone of cells.

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

The antibodies are specific to one binding site on one protein antigen.

Fully explain the process of producing monoclonal antibodies.

• They are produced by stimulating mouse lymphocytes to make a particular antibody.

• The lymphocytes are combined with a particular kind of tumour cell to make a cell called a hybridoma cell.

• The hybridoma cell can both divide and make the antibody.

• Single hybridoma cells are cloned to produce many identical cells that all produce the same antibody.

• A large amount of the antibody can be collected and purified.

Why are tumour cells used when making monoclonal antibodies?

They divide rapidly.

What are four uses of monoclonal antibodies?

• Diagnosis (e.g. pregnancy tests)

• To measure the levels of hormones and other chemicals in blood, or to detect pathogens.

• To locate or identify specific molecules in a cell or tissue by binding to them with a fluorescent dye.

• To treat some diseases (e.g. cancer)

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

A hormone called hCG is present in the urine of women who are pregnant.

• There are two sections of the stick

  • The first section has mobile antibodies complementary to the hCG hormone — these antibodies are also attached to blue beads.

  • The second section has stationary antibodies complementary to the hCG hormone which are stuck down to the stick.

• The individual urinates on the first section.

  • If hCG is present it bind to the mobile antibodies to form hCG complexes.

• They are carried in the flow of liquid to the second section

• The stationary antibodies bind to the hCG complexes.

• Blue dye appears in both control and results zones to show 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.