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Vaccine and memory

The innate immune system reacts quickly and generally: skin, mucus, fever and phagocytes. The adaptive system is slower the first time, but precise. B cells make antibodies against an antigen, and T cells can kill infected cells. Some of the cells become memory cells. The next time the same antigen arrives, the response is faster, and you often do not get ill. A vaccine gives a harmless antigen, so the memory is made without the dangerous infection. Antibiotics work on bacteria and do nothing against viruses, such as the common cold.

antigen→memory→faster response\text{antigen} \rightarrow \text{memory} \rightarrow \text{faster response}adaptive immunity

Symbols

BcellB cellmakes antibodies
TcellT cellkills infected cells

Example

The first meeting with the antigen builds memory.

The second meeting is recognised quickly, whether you were ill or vaccinated.

Antibiotics against viruses give no benefit and can select for resistant bacteria.
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← Bacterial growth

Part of Biology 2: The immune system.