Cells: Cell Recognition & the Immune System - Monoclonal Antibodies

Question 1

What are monoclonal antibodies?

Answer 1

• Monoclonal antibodies are antibodies produced from a single group of genetically identical B-cells (plasma cells)
• So they are all identical in structure
• Monoclonal antibodies are useful in treating illnesses and in medical diagnosis

Question 2

How are monoclonal antibodies used to target cancer cells?

Answer 2

• Different cells in the body have different surface antigens
• Cancer cells have abnormal antigens called tumour markers
• Monoclonal antibodies can be made that will bind to the tumour markers
• You can attach anti-cancer drugs to the antibodies
• Monoclonal antibodies with the drug attached bind to the antigen and deliver the drug

Question 3

Explain why monoclonal antibodies can be advantageous over traditional chemotherapy

Answer 3

• Anti-cancer drugs are toxic chemicals that kill cells
• They cause side effects because they also kill healthy cells
• By using monoclonal antibodies, the drug will only accumulate where the cancer cells are
• So the side effects of antibody-based drugs would be lower than other drugs because they target specific cells

Question 4

How are monoclonal antibodies used in pregnancy tests?

Answer 4

• Hormone
- Pregnancy tests detect the hormone ‘human chrorionic gonadotropin’ (hCG) that’s found in the urine of pregnant women

• Application area

• The application area contains antibodies that are complementary to the HCG protein, which are 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 strip, carrying any beads with it

• Test strip & results

• The test strip contains antibodies to hCG that are immobilised
• If there is hCG present the test strip turns blue because the immobilised antibody binds to any hCG attached to the antibody-blue bead
• If no hCG is present the beads will pass the test area without binding to anything, and so it won’t go blue

Question 5

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

Answer 5

• Ethical issues often relate to animal rights issues
• Animals are used to produce the cells from which the monoclonal antibodies are produced
• Some people disagree with the use of animals in this way