Lecture 24 - Immune Memory Flashcards Preview

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Flashcards in Lecture 24 - Immune Memory Deck (49):
1

Example of ancient documentation of immunological immunity

Thucydides documented immunological memory in his History of the Peloponnesian war
Treating plague

2

What is immunity?

The ability to resist infection after previous exposure
Persists due to immune memory

3

Classic epidemiological study demonstrating immune memory

Faroer Islands
Two measles epidemics. The survivors of the first didn't get infected during the second

4

When was smallpox officially eradicated?

1979

5

Other successful vaccine campaigns
1)
2)
3)

1) Corynebacterium diphtheriae
2) Polio virus
3) Measles virus

6

Difference in memory between humoral and cellular arms of the immune system

Humoral immunity remains constant (stable antibody titres over time)
Cellular immunity declines, with a half life of 10-15 years

7

Cells which a germinal centre B cell can differentiate into
1)
2)

1) Bone marrow plasma cell
2) Memory B cell in lymph nodes or speen

8

Which cell becomes the effector in short-lived extrafollcular antibody production?

Plasmablast

9

Tfh and germinal centre B cell interactions required for immunological memory development
1)
2)
3)
4)

1) CD40/CD40L
2) ICOS/ICOSL
3) TCR/MHC
4) IL21/IL21R (IL21 R on B cell)

10

Frequency of cognate B cells in a primary B cell response

1:10^4 - 1:10^5

11

Frequency of cognate B cells in a secondary B cell response

1:10^2 - 1:10^3

12

Main antibodies produced in a primary response

IgM, later IgG

13

Main antibody isotypes produced in a secondary response

IgG, IgA

14

Antibodies in breastmilk

IgA

15

How long after birth until serum IgG levels reach those of an adult?

~10 years

16

Immune response that most successful vaccines work through

Antibody response

17

Examples of infections that aren't immunised against using a vaccine that elicits an antibody response
1)
2)
3)

1) HIV
2) Mycobacterium tuberculosis
3) Influenza virus

18

Location of naive T cells

Lymphoid

19

Location of memory T cells

Lymphoid and tissues

20

Role of maternal IgA

Protects the GIT of neonate

21

Which cells can an activated T cell differentiate into?
1)
2)

1) Terminal effector cell (90% of T cells become these)
2) Memory cell

22

Phenotype of terminal effector cells
1)
2)

1) IL-7R-
2) KLRG1+ (killer cell lectin-like receptor subfamily G1)

23

Experiment demonstrating the importance of IL-7R and IL-15R
1)
2)
3)
4)

1) Mice infected with an antigen
2) Take IL-7+, IL-7- memory cells from mouse, place into new mice
3) Infect new mice with the same antigen
4) Mice that received IL-7R+ and expressed IL-15 generated stable memory. Mice that received IL-7R+ and didn't express IL-15 had memory die off quickly.

24

Cell surface receptor expressed by effector cells, not memory cells

IL-2R

25

Helpless memory

Poor memory response when DC licensing is blocked (CD40/40L blocked)

26

Subsets of memory T cells
1)
2)

1) Central memory T cells (in lymphoid organs)
2) Effector memory T cells (extra-lymphoid tissues)

27

Phenotype of skin-tropic circulating memory T cells
1)
2)

1) CLA+
2) CCR4+

28

Phenotype of GIT-tropic circulating memory T cells
1)
2)

1) Alpha4:beta7 integrin
2) CCR9+

29

CLA

Cutaneous leukocyte antigen.
An E-selectin ligand expressed by skin-tropic T cells in humans

30

Central memory T cell phenotype
1)
2)

1) CCR7+
2) CD62L+

31

Effector memory T cell phenotype
1)
2)
3)

1) CCR7+/-
2) CD62L-
3) CCR5+

32

Central memory T cell location
1)
2)
3)

1) Blood, lymphoid tissues
2) Lymph nodes
3) Spleen
4) Bone marrow

33

Effector memory T cell location
1)
2)
3)
4)
5)

1) Blood, non-lymphoid tissue
2) Skin
3) Lungs
4) GIT
5) Liver

34

Central memory T cell functional properties
1)
2)
3)
4)

1) Proliferative potential
2) IL-2 expression
3) Recirculation
4) Poor effector function

35

Effector memory T cell functional properties
1)
2)
3)
4)

1) Poor proliferative potential
2) No IL2 expression
3) Recirculation
4) Effector function

36

Acute infection memory T cell response

Mostly effector memory T cells

37

Late memory T cell makeup

Almost all central memory T cells

38

In the skin, where do memory CD8+ T cells cluster?

Epidermis

39

In the skin, where do memory CD4+ T cells cluster?

Dermis, hair follicles

40

Difference in migration patterns in tissue-resident memory T cells
1)
2)

1) CD8+ are fairly static
2) CD4+ move around a lot

41

CD8+ T cells found in the skin

Permanently tissue-resident CD8+ memory cells

42

Permanently tissue-resident CD8+ memory cell phenotype
1)
2)
3)
4)

1) High CD103
2) High CD69
3) CD62L-
4) CCR7-

43

CD103

Adhesion molecule

44

CD69

Involved in migration

45

Comparison between phenotypes of T effector memory and T tissue-resident memory

Similar, but T effector memory have CCR5, and T tissue-resident memory express CD103 and CD69

46

Tissue-resident memory T cell location
1)
2)
3)
4)
5)
6)

1) Mainly non-lymphoid tissues
2) Skin
3) GIT
4) Lungs
5) Brain
6) Particularly common in areas after local inflammation

47

Tissue-resident memory T cell functional properties
1)
2)
3)
4)

1) Probably don't have proliferative potential
2) No IL-2
3) No recirculation
4) Effector function

48

Probable role of tissue-resident memory T cells
1)
2)

1) Sit in places (EG: epidermis) where circulating memory T cells don't go
2) Control persistently or recurrently occurring infections

49

Example of infection controlled by tissue-resident CD8+ memory cells

Herpes simplex virus
Latent in dorsal root ganglia, constant viral reactivation, but controlled by tissue-resident T cells