Immunology

Question 1

What are some of the physiological functions mucosal tissue?

Answer 1

• gas exchange
• food absorption
• sensory activities

Question 2

Why is the gut naturally immune suppressed?

Answer 2

• you don’t want to over-react to non-harmful substances

Question 3

What is Peyer’s patch?

Answer 3

-group of lymphoid tissues found in the ileum of the small intestine

Question 4

What are Peyer’s patches covered in?

Answer 4

• epithelial cells and contain specialised cells called M cells

Question 5

What are M cells?

Answer 5

• found on Peyer’s patches
• have characteristic membrane ruffles - microvilli
• increase surface area –> good at absorption

Question 6

What is found in the germinal centre of the Peyer’s patch?

Answer 6

• T cells

Question 7

How can dendritic cells sample antigens from the lumen of the gut?

Answer 7

• they can extend processes across the epithelial layer

- don’t only need to be in peyer’s patches

Question 8

Where does the immune response occur in mucosa immunity

Answer 8

• lamina propria
• layer of loose connective tissue
• present with many different immune cells

Question 9

What are standard homing receptors in the gut?

Answer 9

• CCR7
• CCR9
• CCR10
• L - selectin
• Think of it as post codes, directs lymphocytes to a specific location

Question 10

Name of the lymph nodes associated with the gut?

Answer 10

• mesenteric lymph nodes

Question 11

What is the most common immunoglobin in the gut?

Answer 11

• IgA

- DIMERIC!

Question 12

Why does the IgA have secretory components?

Answer 12

• as a protection, to prevent it being broken down

Question 13

Why might a baby experience immunodeficiency from 6 months?

Answer 13

• maternal immunoglobulins gone

Question 14

Atypical inflammatory bowel disease in a child?

Answer 14

-CGD –> Chronic Granulomatous Disease

Question 15

How is a food allergy initiated?

Answer 15

• type I hypersensitivity
• imitated by cross linking of allergen, specific IgE on the surface of mast cell with the specific allergen
• memory response

Question 16

For an anaphylaxis reaction the allergen must be intravenous?

True or False?

Answer 16

• TRUE

- Food - oral absorption into the blood

Question 17

What is coeliac disease?

Answer 17

• gluten sensitive enteropathy
• genetically liked, immune disorder
• incurable (stop eating gluten)
• no IgE involved –> not an allergy
• T cell mediated

Question 18

How do you diagnose Coeliac Disease?

Answer 18

• biopsy
• serology (IgA)
• no gluten, no antibody
• IgA defence screening

Question 19

What is Crohn’s disease?

Answer 19

• focal and discontinuous inflammation with deep and eroding fissures
• mediated by Th1 CD4+ T cells
• granulomas

Question 20

What is Ulcerative colitis?

Answer 20

• restricted to rectum and colon
• starts in rectum and moves proximally
• no granulomas
• no treatment –> anti-inflammatory and immunosuppression

Question 21

What are the 2 distinct immunological groups in the gut?

Answer 21

• intraepitelial lymphocytes

- lamina propria lymphocytes