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Flashcards in IgE Immunity Deck (21)
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1
Q

What is Type I Hypersensitivity?

A

Allergic reactions mediated by IgE

2
Q

What is Type II Hypersensitivity?

A

Ab directed against tissue Ag mediated by IgG

3
Q

What is Type III Hypersensitivity?

A

Immune complex mediated disease caused by Ag-IgG complexes

4
Q

What is Type IV Hypersensitivity?

A

Delayed hypersensitivity mediated by T cells

5
Q

What is allergy?

A

It is a disease induced by reaction to a usually innocuous antigen

6
Q

What is atropy?

A

It is a genetic predisposition to develop IgE antibodies upon exposure to environmental allergens

7
Q

What are the major cell mediators of allergy?

A

Basophils
Mast Cells
Eosinophils

8
Q

What do mast cells and basophils bind to?

A

Have high affinity for Fc epsilon receptors

9
Q

Can the FcR epsilon be occupied by Ab without Ag?

A

Yes. It is the only FcR that can do that.

10
Q

What is the main thing required for an allergic reaction?

A

Need to have had previous exposure to have

an allergic reaction

11
Q

What are the important cytokines in an allergic reaction?

A

IL3,4,5,13, and 10.

Especially IL-13 though.

12
Q

How does the Type I Hypersensitivity occur?

A
  1. Contact with allergen and uptake by a DC via an allergic TLR
  2. DC produces IL-4 instead of IL-12 and present allergen as an immunodominant peptide in MHC II
  3. IgE response occurs
13
Q

How does an immunodominant peptide cause an IgE reaction?

A

Immunodominant peptides are preferentially presented in D MHC II which promotes IgE over IgG

14
Q

What are the dominant cytokines in an IgE response?

A

IL-4 and IL-13

15
Q

How does promotion of IgE class switch occur?

A

It occurs via CD23 up regulation which leads to IL-4 and IL-23 up regulation

16
Q

What “arms” the mast cells?

A

IgE binding to them

17
Q

What happens to armed mast cells upon subsequent exposure?

A

They will have the IgE crosslink and linked FcR epsilon will aggregate leading to a singal transduction.

18
Q

What does the signal transduction that occurs in mast cells with cross linking of IgE trigger?

A

Degranulation to release the vasoactive inflammatory mediators like prostaglandin and leukotriene

19
Q

What is the RAST Assay?

A

Radioallergosorbent Test.

Radiolabeled Anti-IgE will bind to the Ab-Ag complex of the IgE to determine the substances that someone is allergic to.

20
Q

What is allergen immunotherapy?

A

Done through shots or sublingually to redirect the immune response

21
Q

What is Anti-IgE therapy?

A

Ab used that binds to IgE to suppress IgE mediated symptoms