IGCSE Biology glossary
Immune response
Biology editorial review is supported by the named review panel. Reviewer participation may vary by guide. Checked against Cambridge IGCSE Biology 0610 (2026–2028); last reviewed August 2026.
Definition
The body's reaction to the presence of a pathogen or foreign substance. The non-specific response involves phagocytes engulfing pathogens. The specific response involves lymphocytes recognising antigens and producing complementary antibodies.
What to include in an exam answer
In vaccination questions, the immune response is faster and stronger on second exposure because memory cells remain from the first exposure, allowing rapid antibody production.
Example in context
Explain why a person who recovers from measles is unlikely to catch it again (3 marks): During the first infection, lymphocytes produce antibodies specific to the measles antigen. Memory cells are formed and remain in the blood. On re-exposure, memory cells rapidly produce large quantities of the correct antibody, destroying the pathogen before symptoms develop.
Related syllabus topic
Diseases & immunity