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How does the immune system work?
Quick answer
The immune system works in two coordinated layers: a fast, general innate response attacks anything foreign immediately, while a slower adaptive response builds antibodies tailored to a specific pathogen — and remembers it for next time. Barriers like skin and mucus block invaders first.
Step by step
- Barriers like skin and mucus block invaders first.
- Innate cells attack anything foreign quickly and trigger inflammation.
- Adaptive immunity makes specific antibodies via B cells and T cells.
- Memory cells remain, so a repeat invader is defeated faster — how vaccines protect you.
People also ask
What are the two main parts of the immune system?
The innate response (fast, general) and the adaptive response (slower, specific, with memory).
How does immune memory work?
After an infection, memory cells persist and recognize the same pathogen, mounting a much faster response next time.
How do vaccines use the immune system?
They safely expose it to a pathogen's signature so it builds antibodies and memory before any real infection.
Part of the guide: How Your Body Works →