Hypersensitivity 2,3,4

Question 1

def. hypersensitivity

Answer 1

immune mediated tissue injury

Question 2

6 cause sof hypersens.

Answer 2

1. allergic rxn
2. some infections
3. autoimmune
4. transplant rej.
5. dysregulated activation of immune system
6. unknown etiology

Question 3

4 classifications of hypersens.

Answer 3

1. IgE mediated
2. mediated by ABs binding to antigens on cell membrane or basement membrane of extracellular matrix
3. immune complex disease
4. delayed-type hypersensitivity and other cell mediated rxns.

Question 4

what is goodpastures

Answer 4

autoantigen- non-collagenous domain of basement membrane

consequnce - glomerulonephritis, pulm. hemmorage

Question 5

4 possible mechanisms of problems in type 2

Answer 5

1. opsinization and phag. (macros of NK)
2. complement and Fc receptor mediated inflammation
3. antibody mediated cellular dysfunction - myasthenia gravis
4. antibodies against RBCs cause autoimmune hemolytic anemia

Question 6

what happens in type 3

Answer 6

antibodies bind to antigen and coause complexes that become deposited in places

Question 7

when is immune complex disease most likely

Answer 7

in equivalence zone - when only a slight excess of antigen

Question 8

5 examples of immune complex disease

Answer 8

1. serum sickness
2. hypersensitivtiy vasculitis (drug reaction)
3. systemic lupus
4. persistent infections
5. mould or plant/animal inhalation

Question 9

2 common problems in type 3

Answer 9

1. vasculitis

2. glomerulonephritis

Question 10

what is type 4

Answer 10

cell mediated- situations where T-cells mediate response, but not antibodies

Question 11

what is mech. in type 4

Answer 11

disease is collateral damage

• normal T-cell response to infectiin (TB)
• abnormal response
• autoimmune response
• alllergic response

Question 12

3 possible functions of effector T-cells

Answer 12

1. Th - exert effects by activating other cells
2. cyto toxic T cells - kill directly
3. produce inflammatory cytokines

Question 13

3 important considerations in type 4

Answer 13

1. what starts the immune response (t- cell activation)
2. type of effector cell generated
3. regulation of the response - Treg, inhib. molecules

Question 14

3 adverse effects of persistent inflammation

Answer 14

1. overproduce TGF-beta
2. fibrosis of tissues, loss of normal cells and functions
3. carcinogenic effects

Question 15

what is importance of TGF-B in cancer

Answer 15

TGF-B can be expressed by cancer cells which turns off immune system

Question 16

important difference between 2 and 3

Answer 16

both Antibody mediated, but 2 is generallyorgan specific, while 3 is systemic

Question 17

what happens in contact hypersensitivity (poispn ivey)

Answer 17

when contact allergen, langerhan cell internalizes and expresses on membrane - activaes T-cells that then cause damage

Question 18

how do superantigens cause attacks

Answer 18

may be produced by bacteria and sudden inflammatory reactions due to over production of cytokines