A veterinary team is developing a vaccine to protect a species of captive mammal from a disease caused by virus Q. The vaccine contains inactive virus particles that retain surface antigen A.
An animal receives one dose of the vaccine. Six weeks later, it receives a booster containing the same quantity of inactive virus particles.
Explain why the inactive virus particles can trigger a specific immune response without causing the full disease.
The table shows the concentration of antibodies specific to antigen A after each dose.
| Time after dose in days | Antibody concentration after first dose in arbitrary units | Antibody concentration after booster in arbitrary units |
|---|---|---|
| 4 | 0 | 40 |
| 12 | 50 | 190 |
Explain how the immune response accounts for both differences in the table.
Soon after the booster response, the animal is exposed to a variant of virus Q in which the shape of antigen A has changed.
Explain why the animal may develop symptoms of the disease.
87 exam-style questions on Edexcel GCSE Biology 5.3 Immune system and medicines, covering 5.3.1 The specific immune system, 5.3.2 Response to immunisation, 5.3.3 Advantages and disadvantages of immunisation, 5.3.4 Antibiotics and bacterial infections, 5.3.5 Aseptic techniques in culturing, 5.3.6 Cross-sectional areas of cultures, 5.3.7 Stages of developing new medicines, and 5.3.8 Production of monoclonal antibodies. Each one has a worked solution and a mark scheme showing where the marks go.