Gut Immunity, Nutrition, and adverse food reactions

Question 1

How is homeostasis in the gut mucosa preserved?

Answer 1

Homeostasis is preserved by secretory IgA-dependent immune exclusion of Ags and by the suppression of proinflammatory responses by induced oral tolerance

Question 2

Describe the process of oral tolerance.

Answer 2

1. Ags are captured by Peyer’s patches in the lamina propria and carried to mesenteric LN by DC.
2. In the LN, DC stimulate expansion of induced Treg cells by a mehcnaism dependent on TGF-beta, retinoic acid and indoleamine -2, 3 - diooxygenase (IDO)
3. DC induce IgA-secreting plasma cells although RA-dependent mechanism.
4. Gut-homing iTregs are expanded in the lamina propria by the IL-10-expressing macrophages.
5. These iTregs can then suppress systemic immune responses, including allergic sensitization, in an Ag-specifc manner.

Question 3

Which vitamins suppress inflammation?

Answer 3

Vit D, A, and folate, and long chain fatty acids

Question 4

What kind of diet promote inflammation?

Answer 4

high-fat diet and medium chain triglycerides

Question 5

The gut microbiota is able to suppress allergic immune response by inducing what cells?

Answer 5

Treg cells, suppressing basophils and mast cells. iTregs also suppress allergic effector cells.

Question 6

What cells provides the effector mechanism of allergy?

Answer 6

IgE, basophils, and mast cells

Question 7

True or false, undernutrition is associated with defects in the innate and adaptive immunity.

Answer 7

True

Question 8

IgE mediated reaction is what kind of hypersensitivity?

Answer 8

Type I hypersensitivity

Question 9

Type III hypersensitivity is mediated by what Ig?

Answer 9

IgG and IgM immune complex.

Question 10

Cell-mediated reaction are what type of hypersensitivity?

Answer 10

Type IV

Question 11

What cell is critical for both local and systemic manifestation of food allergy?

Answer 11

Mast cells

Question 12

GI manifestation of food allergy dependent on which cytokines?

Answer 12

IL4, IL9, IL13

Question 13

What mediates the local acute GI response like diarhea to allergen exposure?

Answer 13

PAF (Platelet activating factor) and serotonin

Question 14

Food allergy occurs in two phase, what are they?

Answer 14

1 Sensitization - the body makes ab against the allergan

2. Allergic reaction - exposure to that same allergen will elicit immune response

Question 15

In food-induced anaphylaxis, mast cells are activated by what immunoglobulin and what does it cross link with?

Answer 15

Mast cells is activated by IgE and cross-links to FceRI. IT can also occur via IgG-induced activation of Macrophages

Question 16

Which mediators of mast cells are responsible for the symptoms seen in food allergy?

Answer 16

histamine and PAF which increase vascular permeability and smooth muscle contractility

Question 17

The complement system exacerbates the symtomps of food allergy and anaphaxis. Which components of the complement system are exudated and what are those components activated by?

Answer 17

Histamine causes vascular permeability and then C3 and C5 comes out. Tryptase released from aciated mast cells act on C3 and C5 to locally generated C3a and C5a.

Question 18

which HLA molecules are the main genetic predisposing factor for celiac disease?

Answer 18

HLA-DQ2 and DQ8

Question 19

Which molecules play a key role in orchestrating an adaptive immune response against gluten peptides?

Answer 19

HLA-DQ2 and HLADQ8

Question 20

In celiac disease, autoantibodies are formed against which enzyme?

Answer 20

tissue transglutaminase 2

Question 21

Celiac disease is what kind of hypersensitivity?

Answer 21

type IV.

Question 22

Gluten is proline-rich protein that is poorly digested in small intestinal tract to lack of what enzyme?

Answer 22

prolylendopeptidases.

Question 23

What two amino acids are abundant in gluten?

Answer 23

Proline and glutamine

Question 24

How does gluten act as antigen?

Answer 24

peptides with a specific spacing of proline and glutamine acid bind to HLA class II on APCs. Majority of CD patients express HLADW2.5 heterodimer.

Question 25

Cross-linking and demaindation of lguten peptides by what enzymes creates potent immunostimulatory epitopes that are present to which HLA on APC?

Answer 25

Transglutaminase 2. presented to HLADQ2 and HLADQ8

Question 26

To initial testing to diagnose CD, you start of measuring what antibody?

Answer 26

IgA antibdoy to transglutaminase