4.1.9 Primary and Secondary Immune Responses

Question 1

How do memory cells work?

Answer 1

• Clonal expansion of T and B cells form memory cells
• Form immunological memory
• Remain in blood for many years or lifetime

Question 2

What is the primary immune response?

Answer 2

• Large time delay
• For clonal selection and expansion of specific T and B cells
• And for synthesis of antibodies (10+ days after pathogen first enters body)
• Why we dont experience symptoms when it first enters
• In primary response, memory cells are produced

Question 3

What is the secondary immune response?

Answer 3

• Second infection with same pathogen
• B memory cells recognise antigen quickly
• Divide by mitosis quickly, differentiate into plasma cells, secreting antibodies
• Memory killer and helper T cells become activated too
• Very quick response, so pathogen is killed quickly