Mucosal Immunology

Question 1

What is the systemic immune system?

Answer 1

Bone marrow, spleen, thymus, lymph system and blood circulation

Question 2

What is the mucosal system comprised of?

Answer 2

Eyes, nose, mouth, lungs, gut, Genitourinary tract

Question 3

What is the main route for infectious microorganisms?

Answer 3

Mucosal immune system

Question 4

What are the two mechanisms within the mucosal immune system?

Answer 4

Innate and adaptive

Question 5

What are the innate mechanisms within the mucosal immune system?

Answer 5

Mucin, peristalsis, antimicrobial peptides and proteins

Question 6

What must the adaptive mechanisms within the mucosal immune system differentiate between?

Answer 6

Harmful pathogens and harmless antigens- foods and commensal bacteria

Question 7

What is in the mucosal barrier?

Answer 7

Secretory IgA/ IgM and a bit of IgG

Question 8

What are the two sources of saliva?

Answer 8

Salivary glands and gum/teeth barrier

Question 9

How is saliva made at the gum epithelium and whys it special?

Answer 9

Epithelium gets really thin where it meets the tooth so fluid from the blood leaks into mouth- no cells only serum components

Question 10

What are intra-epithelial lymphocytes?

Answer 10

Lymphocytes that are squeezing out of the epithelium

Question 11

What are the three types of lymphoid cells in the gut?

Answer 11

Intra-epithelial lymphocytes, lymphocytes and macrophages, Peyers patches

Question 12

Where are the lymphocytes and macrophages found in the gut?

Answer 12

Lamina proprietor

Question 13

What can dendritic cells do in the gut?

Answer 13

Extend their dendrite through the epithelial layer and sample what’s going on in the lumen

Question 14

What are peyers patches similar in structure and function to?

Answer 14

Lymph nodes

Question 15

What are peyers patches full of?

Answer 15

Lymphocytes

Question 16

What’s the structure of peyers patches?

Answer 16

Different types of lymphocytes in different areas of the peyers patch- has columnar epithelium and forms a dome shape. The epithelium is interspersed with M cells

Question 17

Where do M cells lie?

Answer 17

Slightly below epithelial cells

Question 18

What type of cell are M cells?

Answer 18

Antigen presenting cell

Question 19

What are the surface of M cells like?

Answer 19

Have microfolds

Question 20

What are M cells invaginated by?

Answer 20

Lymphocytes

Question 21

What do M cells do?

Answer 21

Take tiny samples of GI fluid

Question 22

What are taken up by M cells?

Answer 22

Viruses, particles and macromolecules, parasites and bacteria

Question 23

What happens if a lymphocyte is activated in a peyers patch?

Answer 23

Proliferates and moves out of the peyers patch into the lymph drainage system

Question 24

What happens after lymphocytes from the peyers patch move into the lymph drainage system?

Answer 24

They go to the mesenteric lymph node where they mature and move into bloodstream- they hone into the small intestine but also all the way along the GIT

Question 25

What is the common mucosal immune system?

Answer 25

Lymphocytes from one area of the GIT will spread evenly along all the mucosal sites

Question 26

What are the main type of mucosal antibodies?

Answer 26

SIgA

Question 27

What is SIgA found in?

Answer 27

All secretions and breast milk

Question 28

What benefits do SIgA give to newborn infants?

Answer 28

Passive immune protection

Question 29

Why do secretory antibodies survive better than the serum antibodies in the gut?

Answer 29

The secretory component protects it from the protease enzymes in the gut

Question 30

What are the main structural differences between secretory and serum antibodies?

Answer 30

Secretory are dimerised, with a joining component and secretory component connecting them, serum are singular

Question 31

What does aggregation mean for bacteria?

Answer 31

Harder to get through the mucosal surface in big groups

Question 32

What gives IgA1 antibodies flexibility?

Answer 32

The hinge region

Question 33

What are the 4 functions of SIgA?

Answer 33

Immune exclusion, intra-cellular neutralisation, virus excretion, interactions with non-specific factors (lysozyme, lactoferrin, peroxidase)

Question 34

What are the 6 approaches to oral immunisation?

Answer 34

- Attenuated virus - attenuated recombinant bacterial mutants - mucosal adjuvants - liposomes, microspheres - capsules - transgenic edible plants

Question 35

What is the difference between mucosal secondary immune response and systemic secondary immune response?

Answer 35

Much smaller and antibodies disappear quite quickly

Question 36

What are the steps in creating an oral vaccine from GM plants?

Answer 36

- hep B surface antigen gene transferred from yeast into a plant cell - potato plants are regenerated from transformed cells - hep B vaccine is correctly expressed by potato plants - GM potatoes are harvested containing the hep B vaccine

Question 37

What is oral tolerance?

Answer 37

If an antigen is first encountered through the mucosal immune system, the systemic immune system may become unresponsive to the antigen

Question 38

Why is oral tolerance a thing?

Answer 38

Prevents immune reactions to all food