Chapter 14: IgE-Mediated Immunity And Allergy

Question 1

Hypersensitivity (allergy)

Answer 1

• a state of increased reactivity due to an environmental antigen (allergen)

Question 2

Hypersensitivity stems from activity of the immune system and…

Answer 2

• involves both antibody-mediated and cell-mediated aspects of immunity

Question 3

Four types of hypersensitivity reaction are cause by different mechanisms

Answer 3

• Type 1 IgE-Mediated Hypersensitivity
• Type 2 Cytotoxic Hypersensitivity
• Type 3 Immune Complex Hypersensitivity
• Type 4 Cellular Hypersensitivity (delayed hypersensitivity)

Question 4

Type 1 IgE-Mediated Hypersensitivity

Answer 4

• a process involving allergens that bind to IgE, which are bound to mast cells, basophils, all of which release mediators that induce smooth muscle contraction
• can vary from runny nose to systemic anaphylaxis (vigorous contractions of smooth muscle in body)

Question 5

Type 2 Cytotoxic Hypersensitivity

Answer 5

• involves IgG, IgM, complement, and the destruction of host cells

Question 6

Typer 3 Immune Complex Hypersensitivity

Answer 6

• involves IgG, IgM, complement, and the formation of antigen-antibody aggregates in the tissue

Question 7

Type 4 Cellular Hypersensitivity (delayed hypersensitivity)

Answer 7

• Cytokines and T lymphocytes function

Question 8

Hypersensitivity reactions fall into four classes on the basis of their…

Answer 8

• mechanism

Question 9

IgE-mediated immune responses defend the body against multicellular parasites

Answer 9

• is caused by IgE antibodies produced in response to certain antigen called allergens
  Examples:
  Hay Fever
  Asthma
  Systemic Anaphylaxis
• Urticaria, angioedema, and eczema are allergic reactions in the skin
• food allergies cause systemic effects as well as gut reactions
• evidence can appear within 30 minutes or less

Question 10

Antibodies can attach to the surface of mast cells, basophil, and activated eosinophils and trigger release of mediators (histamines) on subsequent exposure to the ____________ allergen.

Answer 10

• same

Question 11

IgE binding to FcER1…

Answer 11

• provides mast cells, basophils, and activated eosinophils with antigen receptors

Question 12

Cross-linking of FcER1 on the surface of mast cell by antigen and IgE…

Answer 12

• causes mast-cell activation and degranulation
• mast cells defend and maintain the tissues where they live
• tissue mast cells orchestrate IgE-mediated allergic reaction through the release of inflammatory mediators

Question 13

Molecules released by mast cells on stimulation by antigen binding to…

Answer 13

• IgE

Question 14

Eosinophils are specialized granulocytes that release toxic mediators in IgE-mediated responses

Answer 14

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