Adaptive Response - where and when?

Question 1

Where are most immune responses initiated in?

Answer 1

secondary lymphoid organs

Question 2

What do lymphocytes do once produced?

Answer 2

Travel around body in blood and lymph to meet Ag

Question 3

What are HEV?

Answer 3

High endothelial venules - small blood vessels in lymph nodes that have different structure to other venules

Question 4

How does cell decide to go to lymph node or not?

Answer 4

Afferent leads to lymph node, if Ag there - stay, if not leave

Question 5

Lymph node structure”

Answer 5

Medulla paracortex and cortex

Question 6

Where are B and T cells found in lymph node?

Answer 6

B cells cortexT cells paracortex

Question 7

What do lymphocytes do if they meet Ag in lymph nodes?

Answer 7

Start dividing and form primary and secondary follicles

Question 8

Where is the germinal center?

Answer 8

Within secondary follicle

Question 9

What does dendritic cell usually do (resting to active):

Answer 9

Sits in tissue until meets pathogen. Uses PRR, and engulfes pathogen (phag). Then processes it and moves out to lymph node. No longer Phag but very potent APC with lots of MHCII and B7. Interacts with T cell in lymph node. If cytotoxic T cell - get activated and go to area of infection.

Question 10

What do germinal centers contain?

Answer 10

B, T (fh), DC, FDC, Macrophages

Question 11

Germinal centers are sites of 4

Answer 11

B cell class switch, affinity maturation, memory cell generation, Plasma cell precursor generation

Question 12

Direction of travel in germinal center:

Answer 12

Not definite but:Naive B cell moves from dark zone to basal light to apical light to mature into plasma and memory cells

Question 13

What cell in the secondary lymphoid used to show Ag to BCR?

Answer 13

FDC- more efficient

Question 14

What do Tfh cells do in secondary lymphoid?

Answer 14

Help T cells differentiate

Question 15

Why don’t B cells become plasma cells in GC?

Answer 15

produce lots of Abs and cover up all the Ags

Question 16

What does the spleen usually deal with? vs lymph?

Answer 16

Spleen usually deals with blood infectionsLymph node usually deals with tissue infections

Question 17

What are PALS?

Answer 17

T cell area of white pulp of spleen

Question 18

So are PALS only T cells?

Answer 18

No, they also have follicles with marginal zones and mantle zones containing B cells, in the middle of which you get GC

Question 19

What Ig protects mucousal surfaces? How?

Answer 19

IgA - very important in protecting mucousa.Stops adhesion of pathogens onto mucousal surfaces

Question 20

Describe how dimeric IgA gets to surface of mucousa:

Answer 20

It is made by the plasma cells in the lamina propria next to mucousal cell surface. The dimeric IgA then binds to Poly Ig receptors on the basal side of epithelial cells, get endocytosed, go through epithelial cells to luminal surface. Then a once usable enzyme cuts the receptor off but leaves a secretory component on to protect the IgA from gut enzymes and other mucousal enzymes.

Question 21

What is the back up to IgA used to protect mucousal surfaces?

Answer 21

IgE

Question 22

IgE action to protect mucousa

Answer 22

Mast cells have an FcEpsilon receptor for IgE. If spec pathogen comes, it triggers mast cell to produce things like vasoactive chemicals histamine and eosinophils and leave blood to enter area. Abs and complement are also attracted

Question 23

What is the Peyer’s Patch?

Answer 23

Active Immune area of gut

Question 24

What is the organisation of Peyer’s patch?

Answer 24

Primary and secondary follicle, and germinal center

Question 25

Where are M cells located? What do they do?

Answer 25

Inductive site of villi of gut, takes Ag from outer surface and shows it to lymphocytes underlying the gut

Question 26

What happens in Ag in gut?

Answer 26

M cell takes the antigen and shows it to the underlying lymphocytes.When the lymphocytes are activated they drain into the closest local lymph node (in this case mesenteric) to further activate. Then they find their way back to gut using homing molecules.

Question 27

Gut homing molecule name (how):

Answer 27

MadCAM1 is the gut homing molecule. The lymphocytes underlying the gut imprint on it by making an integrin on their surface that binds to it. After the leave the mesenteric lymph node - find their way to MadCAM1.

Question 28

2 types of communication during the immune response:

Answer 28

Cell-Cell contact or soluble molecule binding to recpetor

Question 29

What are the soluble molecules:

Answer 29

Small secreted proteins that act as messengers between cells

Question 30

Functions of Cytokines (2):

Answer 30

Control haematopoiesis and immune responses

Question 31

How do cytokines work?

Answer 31

Bind to cytokine receptor and initiate intracellular signalling

Question 32

What does intracellular signalling of the cytokine receptor lead to? 2

Answer 32

#NAME?

Question 33

6 Main groups of cytokines and jobs:

Answer 33

1- Interleukins - messengers between leukocytes2- Chemokines - chemotactic3- Tumour Necrosis Factor- pro inflammatory4- Interferons - Interfere with viral replication5- Growth Factors - promote growth and differentiation6- Colony stimulating factors - help produce colonies of cells

Question 34

What do you call it when one cytokine does different jobs?

Answer 34

Pleotrophy

Question 35

Which two cytokines work to class switch, which two stop to class switch:

Answer 35

IL4 and IL5 work to class switchIL4 and IFN gamma stop class switch (IFNy blocks the signal)

Question 36

What do Th2 make to act on B cells: what do they do?

Answer 36

IL2, IL4, IL5 - proliferate and class switchIFNy - stop class switch

Question 37

Which 2 cytokines stim inflammation?

Answer 37

IL 1 and 17

Question 38

Which cytokines are immunosuppressive?2

Answer 38

IL10 and TGFB

Question 39

2 antiviral cytokines are:

Answer 39

IFN a and IFNy

Question 40

Two cytokines leading to T cell proliferation and differentiation are:

Answer 40

IL2 and IL12

Question 41

Two cytokines leading to B cell proliferation and dif are:

Answer 41

IL2 ad IL13

Question 42

2 cytokines controlling haematopoiesis are:

Answer 42

M-CSF and GM-CSF

Question 43

Two chemotactic factors are:

Answer 43

IL8 and CCL5

Question 44

Which 2 cytokines do Th17 make - what do they do:

Answer 44

IL17 and 22 - proinflammatory

Question 45

3 Cytokines that Th2 makes and jobs;

Answer 45

IL4 - Th2 cell dif and B cell class switchIL10 - B cell prolif and suppresses Th1 (antiinf)IL13 - Promotes B cell proliferation

Question 46

2 cytokines that macrophages and Dcs make and jobs:

Answer 46

IL1 - pro inflammatoryIL12 - Promote Th1 diff

Question 47

What cells make IL 10 - use:

Answer 47

Monocytes, Th2 and Treg - antiinflammatory

Question 48

3 types of CSF and jobs:

Answer 48

Granulocyte Macrophage (GM-CSF) - acts early in myeloid developmentMonocyte/Macrophage (M-CSF) -Induces Monocyte differentiationGranulocyte CSF - G-CSF - Induces granulocyte differentiation

Question 49

Example of Cytokine being used therapeutically

Answer 49

IFN alpha for viral infectionsBlocking TNF alpha for RA