Topic 2---C: Cells and The Immune System- 5. Antibodies in medicine

Question 1

What are monoclonal antibodies?

Answer 1

They are antibodies produced from a single group of genetically identical B-cells (plasma cells).

Question 2

How are antibodies very specific?

Answer 2

Because their binding sites have a unique tertiary structure due to different amino acid sequences in the protein (primary structure) that only an antigen with a complementary shape can fit into.

Question 3

What do monoclonal antibodies do?

Answer 3

• They can bind to anything you want and they will only target this molecule.
• Useful for both treating illnesses and in medical diagnosis.

Question 4

What are examples monoclonal antibodies can bind to?

Answer 4

• Cell antigen
• Substances

Question 5

Example of monoclonal antibodies targeting cancer cells

Answer 5

• Different cells in the body have different surface antigens.
• Cancer cells have antigens called tumour markers that are not found on normal body cells.
• Monoclonal antibodies can be made that will bind to the tumour markers.
• You can attatch anti-cancer drugs to the antibodies so when the antibodies come into contact with the cancer cells they will bind to the tumour markers.
• This means the drug in the body will only accumulate in the body where there is cancer cells.

Question 6

Example of monoclonal antibodies for pregnancy

Answer 6

• The application area contains antibodies that are complementary to the hcG protein bound to a coloured bead (blue).
• When urine is applied to the application area any hcG will bind to the antibody on the beads forming an antigen-antibody complex.
• The urine moves up the stick to the test trip carrying any beads with it.
• The test trip contains antibodies to hcG that are stuck in place (immobolised).
• If there is any hcG present the test strip turns blue .
• If there is no hcG present the beads will pass through the test area without binding to anything so it won’t go blue.

Question 7

What does an elisa test allow you to see?

Answer 7

If a patient has any antibodies to a certain antigen or any antigen to a certain antibody.

Question 8

What happens in a Elisa test?

Answer 8

• An antibody is used which has an enzyme attatched to it.
• This enzyme can react with a substrate to produce a coloured product.
• This causes the solution in the reaction to change colour.
• If there’s a colour change it demonstrates that the antigen or antibody of interest is present in the sample being tested.
• Quantity of this antigen/ antibody can be worked out from the intensity of the colour change.

Question 9

What are the ethical issues surrounding the use of monoclonal antibodies?

Answer 9

• Animal right issues- animals are used to produce the cells from which the monoclonal antibodies are produced and some people disagree with the use of animals in this way.