lecture 25 - memory

Question 1

What are some characteristics of antiviral B and T cell immunity

Answer 1

Memory cells survive in antigen absence some for years
Repeated exposure strengthens the memory and keeps it longer
Some infections induce all 3 types of memory cells

Question 2

Compare and contrast the memory B cell response between unimmunized donor primary response (naive)and an unimmunized donor secondary response (memory)

Answer 2

Frequency of antigen specific B cells: 1:104-1:105 vs. 1:102-1:103
Isotype produced: IgM>IgG vs. IgG and IgA
Affinity of antibody: low vs. high
Somatic hypermutation: low vs. high

Question 3

Compare and contrast T cell memory cells and T cell effector cells

Answer 3

Central memory (Tcm)
Reside in and travel between secondary lymphoid tissue
Blood→ secondary lymphoid organs → lymphatics
Long life, more division
Rapid reactivation via secondary antigen exposure, less so than effector

Effector memory (Tem)
Travel to and between tissues, esp inflammed
Blood→ non lymphoid tissues → lymphatics
First line defenses and lots of secretion on IFN-gamma after infection
Very rapid shift to effector T cell functions

Question 4

Describe CCR7, CD62L, CD44 amd CD69

role, naiive, Tcm, Tem

Answer 4

CCr7
Chemokine receptor that regulates homing ot secondary lymphoid organs
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CD62L
Adhesion protein that regulates homing to secondary lymphoid organs
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CD44
Adhesion molecule that increases in response to TCR mediated activation signals and helps in T cell migration
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CD69
C type lectin that prevents immune cells from leaving tissue
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Question 5

How do CD4 helper T cells maintain CD8 memory?

Answer 5

During priming via IL2, in the absence of repeated infections
Particularly with T cell development and expansion

Question 6

Why are Il7 and IL15 needed in memory?

Answer 6

Both memory and naive cells need them for survival and division