Antigen — Science definition
A feature recognized by adaptive immune receptors.
Where it is taught
- Defense, Disease & Homeostasis — Body Systems, Signals & Homeostasis, Life Science: Biology, Grade 10
In use
Vaccination exposes the immune system to selected antigen information under controlled conditions, preparing memory without requiring the full disease.
Defense, Disease & Homeostasis
Questions using antigen
Problem 1
Why does a changed pathogen antigen sometimes reduce previous protection?
Hints
State what the supplied observations or conditions establish, and separate that from any assumption.
Answer and explanation
Recognition depends on molecular features; altered antigens can reduce the match to existing immune responses.
Problem 2
Why compare responses to the same antigen under comparable conditions?
Answer and explanation
Different antigens, doses, timing, or hosts could change the response independently of memory.