Hypersensitivity

Question 1

what mediates type I reaction?

Answer 1

IgE

Question 2

what mediates type II reaction?

Answer 2

IgG/IgM

Question 3

what mediates type III reaction?

Answer 3

IgG/IgM

Question 4

what mediates type IV reaction?

Answer 4

T cells

Question 5

mechanism of type I reaction

Answer 5

occurs in seconds-minutes; antigen binds to two IgE antibodies on mast cells and basophils, releasing mediators that cause vasoconstriction, bronchoconstriction, etc.

Question 6

mechanism of type II reaction

Answer 6

occurs in minutes-hours; IgG/IgM bind to the surface of a cell, causing immune system cells to attack it, and resulting in its death

Question 7

mechanism of type III reaction

Answer 7

occurs in minutes-hours; antigen-antibody complexes deposit in various tissues and activate the complement system, causing inflammation

Question 8

mechanism of type IV reaction

Answer 8

occurs in hours-days; TH1 cells release cytokines which activate cytotoxic T cells and macrophages, resulting in cell damage

Question 9

examples of type I reaction

Answer 9

anaphylaxis: hay fever, asthma, food allergies, eczema, etc.

Question 10

examples of type II reaction

Answer 10

blood transfusion reactions, autoimmune disorders, etc.

Question 11

examples of type III reaction

Answer 11

drug-induced serum sickness, arthritis, etc.

Question 12

examples of type IV reaction

Answer 12

contact dermatitis, graft rejections, etc.