The immune response and memory cells
| English | Chinese | Pinyin |
|---|---|---|
| primary response | 初次反应 | chū cì fǎn yìng |
| T-helper cell | 辅助性T细胞 | fǔ zhù xìng T xì bāo |
| B-lymphocyte | B淋巴细胞 | B lín bā xì bāo |
| plasma cell | 浆细胞 | jiāng xì bāo |
| memory cell | 记忆细胞 | jì yì xì bāo |
| secondary response | 二次反应 | èr cì fǎn yìng |
| clonal selection | 克隆选择 | kè lóng xuǎn zé |
The body fights back
- The first time a new pathogen enters, the response is slow.
- Several cell types work together to destroy it — and to remember it.
- That memory is what makes you immune next time.
Memory cells make the secondary immune response faster and stronger than the first.
Memory cells left from the first exposure react quickly when the same pathogen returns — the basis of long-term immunity.
The primary response 初次反应
- a macrophage engulfs the pathogen and displays its antigen.
- T-helper cells 辅助性T细胞 recognise that antigen, become active, and switch on other cells.
- matching B-lymphocytes B淋巴细胞 are selected; they divide into plasma cells 浆细胞 (which pour out antibodies) and memory cells 记忆细胞.
- T-killer cells destroy the body's own cells that are infected.
A blood smear: the large stained cells are white blood cells among the red cells.
The primary immune response
Step through the specific response — the antigen is presented, T-helper cells switch on B-cells, and plasma cells pour out antibodies.
T-helper cells in the immune response:
T-helper cells recognise the presented antigen and activate B-lymphocytes and other cells.
Which cells actually secrete antibodies?
Selected B-lymphocytes divide into plasma cells (which secrete antibodies) and memory cells.
Put the primary immune response in order.
Antigen presented → T-helper activated → B-lymphocytes selected → plasma cells make antibodies.
Match each cell to its job in the immune response.
The macrophage presents, the T-helper switches things on, plasma cells make antibodies, and memory cells wait for next time.
Memory and the secondary response 二次反应
- Memory cells stay in the body for years.
- If the same pathogen returns, they launch a secondary response that is much faster and larger.
- The pathogen is destroyed before it makes you ill — long-term immunity.
The secondary immune response is faster and larger because:
Memory cells made in the primary response respond quickly and strongly when the same pathogen returns.
Long-lived cells that stay behind to give a fast secondary response are ______ cells.
Memory cells let the body respond before you even feel ill the second time — the basis of immunity.
Clonal selection 克隆选择
- Each lymphocyte has receptors for one specific antigen.
- When that antigen appears, the matching lymphocyte is selected and divides rapidly to make an army of identical cells — clonal selection.
The one lymphocyte whose receptor matches the antigen is selected and cloned into many identical cells
You've got it
- primary response: macrophage displays antigen → T-helper activates → B-lymphocytes → plasma cells (antibodies) + memory cells
- T-killer cells destroy infected body cells
- memory cells persist; the secondary response is faster and larger
- that's long-term immunity — the pathogen is cleared before you fall ill