AQA · GCSE · Biology
Course version: 8461 · Version from Sept 2018
If the same pathogen re-enters the body the white blood cells respond…
Full specification wording
Vaccination: If the same pathogen re-enters the body the white blood cells respond quickly to produce the correct antibodies, preventing infection.
This statement explains immunological memory.
Checked against the AQA 8461 specification (opens in a new tab) on .
- Point 3 of 3
- 4 key terms
Study notes
From the checked teaching notes for this specification point.
The idea
This statement explains immunological memory. After a first exposure, whether through infection or vaccination, some white blood cells remain in the blood as memory cells. On re-entry of the same pathogen, these memory cells recognise the specific antigen immediately. They divide and produce the correct antibodies much faster and in greater numbers than during the first infection. These antibodies bind to antigens on the pathogen, leading to its destruction. Because the antibody concentration rises rapidly before the pathogen can multiply widely, symptoms do not develop, and infection is prevented.
For example: Measles vaccination primes memory cells; later exposure to the measles virus triggers a rapid immune response.
What earns the marks
- Memory cells remain in the blood after a first infection or vaccination and recognise the same antigen on re-entry.
- The immune response is much faster and produces a larger quantity of the specific antibody than the first response.
- White blood cells secrete specific antibodies that bind to antigens on the pathogen, leading to its destruction.
- Because antibodies are produced quickly, pathogen numbers are controlled before symptoms develop, preventing infection.
- Specificity means only the antibody matching that pathogen's antigen is produced, which is why prior exposure matters.
Common mistakes and how to put them right
Saying white blood cells 'remember' the pathogen without naming memory cells.
Put it right by stating that memory cells specific to the antigen remain in the body.
Claiming antibodies kill pathogens directly.
Put it right by explaining that antibodies bind to antigens and help white blood cells destroy the pathogen.
Describing the response as equally slow on second exposure.
Put it right by contrasting the rapid, larger response on re-infection with the slower initial response.
Exam tips
- Use the terms antigen, antibody, and memory cell accurately in your answer.
- When asked to explain immunity, link rapid antibody production to the prevention of symptoms rather than just saying 'you are immune'.
- Practise comparing the first and second immune responses so you can describe the speed and antibody quantity clearly.
Try the lesson
The start of the Vaccination: If the same pathogen re-enters the body the white blood cells respond quickly to produce the correct antibodies, preventing infection. lesson, made from checked teaching notes for this specification point.
Have a go first
A person had chickenpox as a child. Years later the same chickenpox pathogen enters their body again. Why do they not become ill with chickenpox a second time?
Listen
This statement explains immunological memory. After a first exposure, whether through infection or vaccination, some white blood cells remain in the blood as memory cells. On re-entry of the same pathogen, these memory cells recognise the specific antigen immediately. They divide and produce the correct antibodies much faster and in greater numbers than during the first infection. These antibodies bind to antigens on the pathogen, leading to its destruction. Because the antibody concentration rises rapidly before the pathogen can multiply widely, symptoms do not develop, and infection is prevented. For example, measles vaccination primes memory cells; later exposure to the measles virus triggers a rapid immune response. A strong answer earns marks for these points. Memory cells remain in the blood after a first infection or vaccination and recognise the same antigen on re-entry. The immune response is much faster and produces a larger quantity of the specific antibody than the first response. White blood cells secrete specific antibodies that bind to antigens on the pathogen, leading to its destruction. Because antibodies are produced quickly, pathogen numbers are controlled before symptoms develop, preventing infection. A common slip: Saying white blood cells 'remember' the pathogen without naming memory cells. Instead, stating that memory cells specific to the antigen remain in the body. Exam tip: Use the terms antigen, antibody, and memory cell accurately in your answer.
Key words
Say what each word means before you turn the card.
Immunological memory
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Antigen–antibody binding
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Prevention of infection
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Specific immune response
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See every definition
- Immunological memory
- Some white blood cells remain in the blood as memory cells after a first exposure, whether through infection or vaccination.
- Antigen–antibody binding
- White blood cells secrete specific antibodies that bind to antigens on the pathogen, leading to its destruction.
- Prevention of infection
- Because antibodies are produced quickly, pathogen numbers are controlled before symptoms develop, preventing infection.
- Specific immune response
- Specificity means only the antibody matching that pathogen's antigen is produced, which is why prior exposure matters.
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