Hypersensitivity

Question 1

How many mechanisms of hypersensitivity are there

Answer 1

4

Question 2

what are the 2 phases of hypersensitivity

Answer 2

sensation stage
pathological stage

Question 3

What happens during the sensation stage

Answer 3

Immune response occurs as result of binding to an antigen

Question 4

what happens during the pathological stage

Answer 4

immune system drives tissue damage in response to immunological mechanisms

Question 5

What immune cells are involved in the allergic response

Answer 5

IgE
mast cells
eusinophils

Question 6

what effector cells are involved in the allergic immune response

Answer 6

TH2

Question 7

How are allergic responses regulated?

Answer 7

regulatory T cells
parasites secrete factors which can dampen the immune system

Question 8

What can cytokines secreted by TH2 cause other cells to do

Answer 8

cause plasma cells to class switch produced IgE antibodies
cause recruitment of eusoniphils

Question 9

How is the half life of IgE antibodies prolonged

Answer 9

by binding to receptors on basophils and mast cells

Question 10

What happens when a basophil bound to IgE re-encounters an allergen

Answer 10

fast response
degranulation
release histamine

Question 11

What is the allergic phase

Answer 11

release of histmaine
increased expression of pro-inflammatory cytokines

Question 12

What is the hygiene hypothesis

Answer 12

cleaner environment - less exposure to microbes
immune system is not “trained” well

Question 13

What parts of the body are commonly effected by allergens

Answer 13

lungs (bronchioles)
skin
gut

Question 14

What skin condition is called by allergens

Answer 14

urticaria

Question 15

what respiratory condition is caused by allergens

Answer 15

asthma - restriction of the bronchioles

Question 16

How can the type 1 hypersensitivity response be managed

Answer 16

prevention of degranulation
anti-inflammatory agents
steroids - dampen immune system

Question 17

Which hypersensitivity mechanism uses surface/membrane bound antigens

Answer 17

Type 2

Question 18

How is type 2 hypersensitivity activated

Answer 18

IgM
IgG
antibodies directed towards antigens on cell surface

Question 19

What are the possible results of type 2 reactions

Answer 19

destruction of cells with ‘positive’ self antigens

Question 20

How are self-cells killed in type 2 sensitivity

Answer 20

antigen-antibody complex acts as an opsonin
phagocyte engulfs cell

Question 21

What complement system can be activated as result of type 2

Answer 21

classical

Question 22

What happens if an antibody binds to a thyroid cell during type 2 mechanism

Answer 22

can cause an overactive thyroid

Question 23

What type of antigens are involved in the type 2 mechanism

Answer 23

membrane/self-cell surface

Question 24

How does a type 3 mechanism occur

Answer 24

soluble antigen-antibody complexs
get lodged in capillaries between endothelial cell and basement membrane

Question 25

What can the type 3 mechanism activate

Answer 25

classical complement pathway
vasodilation
neutrophils attracted to area

Question 26

How does the type 3 mechanism cause massive inflammation

Answer 26

neutrophils gather at site
discharge killing methods
promotes inflammation/tissue death

Question 27

What is the type 4 mechanism also known as

Answer 27

delayed type hypersensitivity

Question 28

Which immune cell drives type 4

Answer 28

CD4+T

Question 29

What effector cells in involved in type 4

Answer 29

TH1

Question 30

What does the activation of CD4+ cause

Answer 30

proliferation and differentiation into TH1
macrophage recruitment/activation

Question 31

What are the classical signs of delayed type hypersensitivity

Answer 31

large number of macrophages at site
granulomas

Question 32

How do granulomas form

Answer 32

pathogens/foreign bodies that can’t be cleared

Question 33

How are TH1 cells activated

Answer 33

antigen presenting macrophages

Question 34

which hypersensitivity mechanism is not directly driven by antibodies

Answer 34

type 4