HIV/AIDS and vaccination
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Flip to reveal answersWhat does HIV stand for, and what does it destroy?
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All 13 Flashcards — HIV/AIDS and vaccination
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Question
What does HIV stand for, and what does it destroy?
Answer
**Human Immunodeficiency Virus** — it infects and destroys **helper T-cells**.
Question
What is the difference between HIV and AIDS?
Answer
**HIV** is the virus; **AIDS** is the late stage of infection, when helper T-cell numbers are so low the immune system collapses.
Question
Why is destroying helper T-cells so damaging?
Answer
Helper T-cells **activate other immune cells** (including B-cells that make antibodies), so losing them cripples the whole immune response.
Question
What are 'opportunistic infections'?
Answer
Infections that take hold because the immune system is too weak to stop them — a hallmark of **AIDS**.
Question
What usually causes death in someone with AIDS?
Answer
**Opportunistic infections and cancers** that a healthy immune system would normally prevent — not the virus directly.
Question
Define an antigen.
Answer
A molecule (often on a pathogen's surface) that the immune system **recognises as foreign** and responds to.
Question
Define an antibody.
Answer
A **Y-shaped protein** that binds to **one specific antigen**, marking the pathogen for destruction.
Question
What is a vaccine?
Answer
A **harmless** preparation of a pathogen's antigens that triggers **immunity (memory)** without causing the disease.
Question
Outline how a vaccine produces immunity.
Answer
Harmless **antigen** → **primary response** (antibodies) → **memory cells** form → faster, larger **secondary response** on real infection.
Question
What is immunological memory?
Answer
The ability of the immune system to respond **faster and more strongly** the second time it meets the same antigen, thanks to **memory cells**.
Question
Why is the secondary response faster and larger than the first?
Answer
**Memory cells** from the first exposure are already present, so antibodies are made **quickly and in greater numbers**.
Question
How can a falling helper T-cell graph explain worsening symptoms?
Answer
As the **count drops** over years, the immune response weakens, so the patient suffers more **opportunistic infections** — progressing to **AIDS**.
Question
Why is there still no simple vaccine for HIV?
Answer
HIV destroys the very **helper T-cells** a vaccine relies on to build immune memory.
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Topic 3.7 hub
Defence against infectious disease
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