Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

BSMS 204- Theme 1 > Lecture 13- Mucosal Immunology 2 > Flashcards

Lecture 13- Mucosal Immunology 2 Flashcards

1
Q

Where are the mesenteric lymph node located?

A

These mesenteric lymph nodes are located at the base of the mesentry.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is the function of these meseneteric lymph node?

A
  • They collect lymph, cells and antigens from the intestinal mucosa
  • main site for oral tolerance
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is oral tolerance?

A

-Avoidance of an immune response to foodstuff

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

How is oral tolerance induced?

A

Induce tolerance to allergens e.g. eat honey to treat bee venom allergy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is mesentry?

A
  • double fold of peritoneum that attaches the gut to the posterior abdominal wall
  • has been considered an oragan
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What does the mesenteric lymph node drain?

A

-Mesenteric lymph node from intestinal mucosa

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What happens to food antigens?

A

Many food antigens will bypass lymphatic tissue and reach the liver through the portal vein
-immune cells in the liver sinuses have an important function in protecting us from microbes in the portal vein.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is the main of passing blood through the liver sinuses?

A

The main program is tolerance production, in some instances, protective immune response need to be raised

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Where are the intraepithelial lymphocyte located?

A

intra-epithelial cells are located in the basolateral part of the epithelium

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Describe the inra-epithelial lymphocytes?

A
  • Have an irregular shape
  • have long extensions in close contact with neighbouring epithelial cells
  • occur in variable numbers along the gut
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What percentage of intra-epithelial are eosinophils?

A

12% of eosinophils in the intra-epithelial cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What three groups are the intra-epithelial cell can be divided into?

A

1) TCRab+CD8ab+
2) TCRab+ CD8aa+

3) TCRab+CD4

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Describe the pathway when a virus infects a epithelium cell?

IEL=intraepithelial lymphocyte

A
  • Virus infects mucosal epithelium cell
  • Infected cell displays viral peptide to CD8 IEL via MHC class I
  • Activated IEL kills infected epithelial cell by perforin/granzymes and Fas dependent pathway
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What happens to the infected epithelial cell?

A
  • Epithelial cells undergo stress as a result of infection, damage or toxic peptides and express MIC-A and MIC-
  • MIC-A and MIC-B are ligands for the NK cell activating receptor NKG2D which is also found on CD8aa+Tcells
  • NKG2D on IEL binds MIC-A and B and activates the IEL. CD8aa homodimers also bind to TL
  • Activated IEL kills the stressed cell via perforin/granzyme pathway
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is the T cell differentiation is influenced by?

A

epithelial cells and DC

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

what do the T reg cells produce and what is their function?

A

IL-10- required for maintaining food tolerance and class switch including TGF-beta and other mediators

17
Q

What is the function of Th1 T cells?

A

Produce IFN-y and important in killing virally infected epithelial cells

18
Q

What is the function of Th2 T cells?

A

Th2 T cells may be induced by worm infestation

-Produce IL-4 and IL-13 which increase fluid secretion, mucus secretions, bowel motility and smooth muscle contraction

19
Q

What is the function of Th17 cells?

A

Th-17 cell produce IL17 and IL-22 which interact with tge receptors on the epithelial cells to regulate the production of mucins or defensins

20
Q

what is the function of the dendritic cells?

A
  • Sit in lamina propria
  • Have long extensions reaching through the epithelium to sample the contents of intestinal tube
  • present antigen to T cells
21
Q

describe the journey of B cells?

A

Peyer’s patch –> mesenteric lymph node –> lymphatic stations –> thoracic duct –> venous blood –> lung –> arterial blood –> small arteries –> smallest arteries –> effector sites –> IgA secretion –> ?

22
Q

How does the IgA get into the mucus?

A

The poly-Ig receptor at the basal surface of the epithelial cells can bind to the J chain of the IgA and to lesser extent IgM

  • allows the trans-endothelial of IgA /IgM
  • this mechanism helps enriching these immunoglobulins in the mucus where they exert their function
23
Q

Explain the fucntion mucosal IgA?

A
  • IgA is the main mucosal antibody in the secretions
  • IgA against food antigens provides immune exclusion
  • IgA activates the complement system weakly
  • Secretions of the IgA (coupled to J chains) depends on the trans-cellular transport mechanism
24
Q

what does the gut homing of B-cells and T cells depend on?

A

-Depends on retinoic acid derived from dietary vitamin A

25
Q

Describe the process of conversion of vitamin A to retinoic acid by the dendritic cells(DC)?

A

DC in the gut associated tissue (including Peyers patch and mesenteric lymph nodes) are induced by thymic stromal lymphopoietin (TSLP) and other factors to express:
Retinaldehyde dehydrogenase
-This enzyme converts dietary vitamin A to retonoic acid

26
Q

What happens to activated B cells or T cells that are exposed to retonoic acid?

A

-Induces expression of the chemokine receptor CCR9 and the integrin a4b7 on the plasma cells and the effector T cells

27
Q

what happens to the effector T cells once the chemokine receptor is induced?

A

The effector T cells enter the circulation and home back into the gut lamina propria

28
Q

Why does the effector T cells home back to the lamina propria?

A
  • Imprinting of CCR9 and a4b7 receptors on the lymphocytes in the inductive sites
  • The CCL25 (ligand for the CCR9) and the adhesion molecule MadCAM (ligand for a4b7) are displayed on the lamina propria venular endothelial cells
29
Q

Explain what drives the homing process for the effector cells?

A
  • Different combinations of homing receptors will guide effector cells to the different tissues
  • Tissue sites upregulation of the respective ligand molecules will be related to the situation in these tissues
30
Q

what is the effect of the Vitamin A deficiency?

A

–reduced oral tolerance due to reduced homing of regulatory T cells

BSMS 204- Theme 1 (21 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions