32. Primary and secondary immune response. Immune memory.

Question 1

Primary and secondary immune response

Answer 1

Primary Immune Response:
-Occurs: First encounter with antigen.

Phases:
1.Latent Period: 3-4 days, antigen recognition.
2.Exponential Phase: 4-5 days, antibody titer rises.
3.tationary Phase: ~10 days, peak antibody level.
4.Downtime Period: 10-15 days, antibody level declines.

Secondary Immune Response:
-Occurs: Subsequent encounters with the same antigen.

Phases:
1.Latent Period: Few hours, much shorter.
2.Exponential Growth: Rapid, 1-2 days.
3.Higher Peak: Higher antibody titer.
4.Longer Attenuation: Prolonged decline phase.

Cause: Immune memory B and T cells divide and become effector cells upon antigen re-exposure.

Question 2

Immunological memory

Answer 2

Definition:
-Lifelong immunity to infections after initial exposure or vaccination.

Cellular Basis:
-Lymphoid Organs: Contain naive, effector, and memory lymphocytes.

Primary Response:
-Naive Cells: Encounter antigen, proliferate, and differentiate.
-Effector Cells: B cells produce antibodies; T cells kill infected cells or secrete cytokines.
-Memory Cells: Formed from some antigen-stimulated naive cells.

Secondary Response:
-Memory Cells: Respond faster and more efficiently, proliferate, and form more effector and memory cells.