Mucosal Immunology

Question 1

What is mucosa-associated lymphoid tissue (MALT)?

1 - group name for all lymphoid tissue grouped together
2 - lymphoid tissue close to mucosal membranes
3 - lymph nodes in mucosa
4 - small concentration of lymphoid tissue in submucosal membranes

Answer 1

4 - small concentration of lymphoid tissue in submucosal membranes
- located in various submucosal membrane sites of the body, such as the gastrointestinal tract, nasopharynx, thyroid, breast, lung, salivary glands, eye, and skin

Question 2

The mucosa-associated lymphoid tissue (MALT) is small concentrations of lymphoid tissue located in various submucosal membrane sites of the body, such as the gastrointestinal tract, nasopharynx, thyroid, breast, lung, salivary glands, eye, and skin. Why is MALT so important?

Answer 2

• in continual contact with the outside world

- continuously stimulated with antigens

Question 3

Which types of cells populate the mucosa-associated lymphoid tissue?

1 - T cells, basophils and neutrophils
2 - Neutrophils, B and T cells
3 - Macrophages, neutrophils and T cells
4 - macrophages, neutrophils and B cells

Answer 3

2 - Neutrophils, B and T cells

Question 4

Mucosa associated lymphoid tissue (MALT) is scattered around the body. Using the mnemonics below what are the sites where MALT is located?

LALT
GALT
NALT
SALT 
BALT 
VALT

Answer 4

LALT: Larynx associated lymphoid tissue
GALT: Gut associated lymphoid tissue
NALT: Nasal associated lymphoid tissue
SALT (Skin-associated lymphoid tissue), CALT (conjunctiva-associated lymphoid tissue), TALT (Eustachian tube-associated lymphoid tissue),
BALT (Bronchus-associated lymphoid tissue)
VALT (Vulvo-vaginal associated lymphoid tissue)

Question 5

What is the difference between effector and memory cells in the immune system?

Answer 5

• effector cells are those involved in the right now action such as plasma and activated cytotoxic T cells
• memory cells are cells that remain in case the same antigen is presented again

Question 6

There are a number of defence strategies of oropharynx and intestinal mucosa. The epithelial cells and tight junctions make up which component of the defence strategy?

1 - mucins
2 - antimicrobial proteins
3 - specialised cells
4 - mechanical barrier

Answer 6

4 - mechanical barrier

Question 7

There are a number of defence strategies of oropharynx and intestinal mucosa. There is an extensively glycosylated protein that lines the surface of mucosa epithelial cells. Which component of the defence strategy are these part of?

1 - mucins
2 - antimicrobial proteins
3 - specialised cells
4 - mechanical barrier

Answer 7

1 - mucins

Question 8

There are a number of defence strategies of oropharynx and intestinal mucosa. Cells including goblet cells, absorptive epithelial cells, M cells and Paneth cells are part of which component of the defence strategy?

1 - mucins
2 - antimicrobial proteins
3 - specialised cells
4 - mechanical barrier

Answer 8

3 - specialised cells

Question 9

There are regional immune systems in the body. What is the name given for the group of tonsils, including the lingual and palatine tonsils, nasopharyngeal tonsils?

1 - Waldeyer’s ring
2 - Peyer´s patches
3 - Mesenteric lymph nodes
4 - Tensilular ring

Answer 9

1 - Waldeyer’s ring

Question 10

There are regional immune systems in the body. One of these is a small mass of lymphatic tissue found throughout the ileum region of the small intestine

1 - Waldeyer’s ring
2 - Peyer´s patches
3 - Mesenteric lymph nodes
4 - Tensilular ring

Answer 10

2 - Peyer´s patches

Question 11

There are regional immune systems in the body. There are lymph nodes that aggregate around the GI tract. What is this regional immune system called?

1 - Waldeyer’s ring
2 - Peyer´s patches
3 - Mesenteric lymph nodes
4 - Tensilular ring

Answer 11

3 - Mesenteric lymph nodes

- mesenteric relates to the folds of membrane located close to the GIT

Question 12

Which of the following regional immune systems in the body contain germline centres for B and T cells?

1 - Waldeyer’s ring
2 - Peyer´s patches
3 - Mesenteric lymph nodes
4 - Tensilular ring

Answer 12

2 - Peyer´s patches

Question 13

What is an effector site in the mucosa-associated lymphoid tissue (MALT)?

Answer 13

• site where activated immune cells are present (lamina propria)
• B, plasma and T cells

Question 14

What is an inductor site in the mucosa-associated lymphoid tissue (MALT)?

1 - site where active B, T and plasma cells are found
2 - site where B and T cells are activated/induced
3 - site where B and T cells develop
4 - site where B and T cells go through central tolerance

Answer 14

2 - site where B and T cells are activated/induced

• naive cells and antigen presenting cells (APC) are located here
• APCs induce naive B and T cells at this location
• generally payers patch

Question 15

What are the 2 locations in the GI tract where lymphoid tissue is most concentrated?

1 - oropharynx and terminal ileum
2 - nasopharynx and small bowel
3 - oropharynx and small bowel
4 - nasopharynx and terminal ileum

Answer 15

1 - oropharynx (Waldeyer’s ring) and terminal ileum (Peyer’s patches)

Question 16

What is the lamina propria?

Answer 16

• area of connective tissue behind the epithelial cells of the GIT
• they contain activate immune cells

Question 17

There is a specialised cell within the GI that is important for continually monitoring the microorganisms and eco-enviroment of the GIT. They are able to engulf antigens via endocytosis and then present the antigen to antigen presenting cells. What are these cells called?

1 - parietal cells
2 - M cells
3 - I cells
4 - payers cells

Answer 17

2 - M cells

- think M for monitoring

Question 18

Once B and T cells have been activated in the payers patch they travel throughout the circulation before ending up in a site of the body that they are drawn to because of the receptors that change when the cells are activated. What location are they attracted to in the body?

1 - mesenteric lymph nodes
2 - kidneys
3 - spleen
4 - lamina propria in GIT

Answer 18

4 - lamina propria in GIT

- activated cells contain honing receptors to tell them where to go

Question 19

What are the 2 induction sites in the GIT?

1 - mesenteric lymph nodes and M cells
2 - mesenteric lymph nodes and spleen
3 - payers patch and mesenteric lymph nodes
4 - payers patch and M cells

Answer 19

3 - payers patch and mesenteric lymph nodes

Question 20

There is a cell contained within the epithelium of the GIT that are able to release granules containing antimicrobial peptides that are involved in regulating the gut microbiota. What are these cells called?

1 - M cells
2 - Paneth cells
3 - Goblet cells
4 - Epithelial cells

Answer 20

2 - Paneth cells

- remember Paneth release Peptides that are antimicrobial

Question 21

On the epithelial cells of the GIT there are a group of pattern recognition receptors (PRR) that are specifically able to sample and monitor the gut microbiota, assessing for the risk of infection. Which PRR is this?

1 - toll like receptor 5
2 - toll like receptor 1
3 - NOD-5
4 - NOD-1

Answer 21

1 - toll like receptor 5

- able to tighten the tight junctions between epithelial cells

Question 22

Where are the majority of payers patches located in the GIT?

1 - distal ileum
2 - proximal ileum
3 - jejunum
4 - duodenum

Answer 22

1 - distal ileum

Question 23

There are a number of different lymphatic vessels that carry lymph and lymphocytes around the body. What is the name of the vessels where B and T cells enter the follicle contained within the payers patch?

1 - Low Endothelial Venules
2 - High Endothelial Venules
3 - Middle Endothelial Venules
4 - Intermediate Endothelial Venules

Answer 23

2 - High Endothelial Venules

Question 24

Once a naive B and T cell is in the follicles of the payers patch they can be activated. How does this occur?

Answer 24

• M cell binds antigen and presents to APC
• APC presents antigen on MHC-II to B and/or helper T cells
• activates helper T cells
• B cell can be activated by T cells or independently

Question 25

Once a B cell has been activated by the T helper cell, the T helper cell secretes cytokines that causes the class switching of antibodies from IgM or IgG to what antibody? 1 - stays as IgG 2 - IgA 3 - IgM 4 - IgD

Answer 25

2 - IgA | - most abundant antibody in the GIT

Question 26

Once B and T cells have been activated they leave the inductions sites (payers patch and mesenteric lymph nodes) and enter the circulation via what vessels? 1 - Low Endothelial Venules 2 - High Endothelial Venules 3 - Middle Endothelial Venules 4 - thoracic duct

Answer 26

4 - thoracic duct

Question 27

IgA is the main antibody involved in gut associated lymphoid tissue. What 2 functions is IgA able to perform? 1 - neutralise antigen and bind and place antigen back into lumen 2 - bind with M cell and activate B cells 3 - neutralise antigens and police the lamina propria

Answer 27

1 - neutralise antigen and bind and place antigen back into lumen

Question 28

IgA is the main antibody involved in gut associated lymphoid tissue. Low levels of IgA in children has been associated with what? 1 - constipation 2 - irritable bowel syndrome 3 - food allergies 4 - inflammatory bowel disease

Answer 28

3 - food allergies

Question 29

There is a growth factor that is involved in the tolerance to food antigens, and is able to do the following: - regulate central tolerance in thymus - maintains homeostasis of the naïve T-cell pool (peripheral tolerance) - inhibits cytotoxic T cells (peripheral tolerance) - maintains cell proliferation (B cells and innate cells) What growth factor is this? 1 - fibroblast growth factor 2 - insulin 3 - transforming growth factor 4 - epidermal growth factor

Answer 29

3 - transforming growth factor

Question 30

Once a B and T cell has been activated at the induction site (payers patch and mesenteric lymph nodes) what metabolite is produced? 1 - tryptophan 2 - retinoic acid 3 - bakuchiol 4 - eicosanoic acid

Answer 30

2 - retinoic acid

Question 31

Once a B and T cell has been activated at the induction site (payers patch and mesenteric lymph nodes) they are exposed to the metabolite retinoic acid. What cell creates this and what vitamin is required? 1 - macrophages and vitamin A 2 - macrophages and vitamin D 3 - dendritic cells and vitamin A 4 - dendritic cells and vitamin D

Answer 31

3 - dendritic cells and vitamin A

Question 32

Once and activated B and T cell have been activated and exposed to retinoic acid, they undergo synthesis of receptors. What 2 receptors are then exposed on the B and T cell surface membrane? 1 - chemokine CCR9 and integrin α4β7 2 - chemokine CCR19 and integrin α4β8 3 - interleukin 6 and integrin α4β7 3 - interleukin 1 and integrin α4β7

Answer 32

1 - chemokine CCR9 and integrin α4β7 | - important in honing B and T cells from inductor to effector site