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Question
When our body encounters a pathogen for the first time, the immune response is generally low, but on exposure to the same pathogen again, the immune response by the body is much more compared to the first exposure. Why is it so?
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Answer
Why is the second immune response stronger?
First exposure to the pathogen
The body has never met this germ before
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The response is slow and weak
The immune system is still learning to recognise it
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The immune system remembers
It keeps a memory of that pathogen
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Second exposure to the same pathogen
It is recognised at once
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The response is much faster and much stronger — this is acquired immunity
The immune system remembers the pathogen from the first exposure, so it acts faster and stronger the next time.
Explanation
- On first exposure, the body is learning to fight the new pathogen, so the response is slow.
- The immune system remembers that pathogen afterwards.
- On the second exposure, it recognises the germ at once and fights it quickly and strongly.
The body remembers the germ, so the second response is much faster and stronger.
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