3.2 Monoclonal Antibodies

Question 1

what are monoclonal antibodies (mAbs)?

Answer 1

• antibodies that are clones from one parent cell
• specific to one type of antigen

Question 2

describe how monoclonal antibodies are produced

Answer 2

1. specific antigen injected into an animal (e.g. mouse).
2. b-lymphocytes producing complementary antibodies extracted.
3. b-lymphocytes fuse with myeloma cels to form hybridoma cells - these cells can divide and produce antibody.
4. hybridoma cells cultured.
5. monoclomal antibodies collected and purified.

Question 3

outline the uses of monoclonal antibodies

Answer 3

• detection of pathogens
• location of cancer cells and blood clots
• treatment of cancer
• used in pregnancy test kits

Question 4

what are myeloma cells?

Answer 4

type of tumour cell

Question 5

outline the use of monoclonal antibodies

Answer 5

• detection of pathogens
• location of cancer cells and blood clots
• treatment of cancer
• used in pregnancy test kits

Question 6

what do pregnancy kits test for?

Answer 6

hCG in urine

Question 7

what does a pregnancy test consist of?

Answer 7

a stick containing monoclonal antibodies (mAbs) specific to hCG:
- mAbs attached to a blue bead (free to move)
- mAbs fixed to the test stick

Question 8

describe what happens to the test stick if a woman is pregnant

Answer 8

• hCG in urine binds to mAbs attached to a blue bead.
• mAbs with hCG diffuse up dipstick.
• mAbs fixed to the stick bind to hCG.
• blue line forms.

Question 9

describe what happens to the test stick if the pathogen is not present

Answer 9

no hCG in urine so a blue line is not formed.

Question 10

what is the advantage of using monoclonal antibodies to test for pathogens?

Answer 10

• specific to one particular antigen
• very accurate
• quick results

Question 11

why can monoclonal antibodies be used to target cancer cells?

Answer 11

• cancer cells have specific antigens called ‘tumour markers’ on their membranes.
• mAbs are specific to one type of antigen so can be targeted to ‘tumour markers’ without damaging other cells.

Question 12

describe how monoclonal antibodies can be used to diagnose cancer

Answer 12

• mAbs tagged to a radioactive substance.
• mAbs injected into the patient’s bloodstream.
• mAbs bind to ‘tumour markers’ on cancer cells.
• emitted radiation is detected using a specialised scanner enabling doctors to determine the location of cancer cells.

Question 13

how can monoclonal antibodies be used to target drugs to cancer cells?

Answer 13

• mAbs attached to an anti-cancer drug.
• mAbs injected into the patient’s bloodstream.
• mAbs bind to ‘tumour markers’ on cancer cells.
• anti-cancer drug destroys cancer cells.

Question 14

why are cancer treatments that use monoclonal antibodies favoured over traditional treatments?

Answer 14

• radiotherapy and chemotherapy target rapidly dividing cells.
• healthy cells (e.g. hair follicle cells, bone marrow cells) are damaged as a consequence, producing unpleasant side effects.
• mAbs only target cancer cells, reducing damage to normal cells.

Question 15

how can monoclonal antibodies be used to locate blood clots?

Answer 15

• mAbs tagged to a radioactive substance.
• mAbs target and bind to specific proteins in blood clots.
• radiation emitted by mAbs is detected, enabling the location of blood clots to be identified.