Lecture 28: Type II-IV Hypersensitivities

Question 1

Type II hypersensitivity reactions occur through production of what Ig’s

Answer 1

IgM or IgG

Question 2

What type of hypersensitivity reactions are myasthenia gravis and Pemphigus

Answer 2

Type II

Question 3

What happens during sensitization phase of type II hypersensitivity reactions

Answer 3

Exposure to antigen leads to production of IgG or IgM

Question 4

What occurs during effector phaser of hypersensitivity reactions

Answer 4

Re-exposure to antigen allows allergen specific IgM or IgG to bind causing immune mediated damage or blocks normal function of cells/tissues

Question 5

What are some effector phase mechanisms in type II hypersensitvities

Answer 5

ADCC, complement mediated lysis (MAC), and antibody interference

Question 6

What type of hypersensitivity is secondary IMHA

Answer 6

Type II

Question 7

What causes secondary IMHA

Answer 7

Immunologic response against non-self antigens that have absorbed or modified normal RBC’s

Antibodies bind to antigens on RBC’s resulting in lysis

Question 8

What type of hypersensitivity reaction are transfusion reactions

Answer 8

Type II

Question 9

What causes transfusion reactions

Answer 9

Reaction to blood group antigens mediated by antibodies that bind and lyse transfused RBC’s

Question 10

What tests should be run to prevent transfusion reactions

Answer 10

Blood typing and cross matching

Question 11

What type of hypersensitivity reaction is neonatal iseoerthyrolysis

Answer 11

Type II

Question 12

What causes neonatal iseoerthrolysis

Answer 12

Foal is Aa+ and mare is Aa- therefore producing anti-Aa antibodies in milk, resulting in mismatched blood group maternal antibodies that bind and lyse neonatal RBC’s

Question 13

What commonly causes maternal AB’s to arise and cause neonatal isoerythrolysis

Answer 13

Repeated pregnancies

Question 14

What are some diagnostic tests that can be performed for type II hypersensitivities

Answer 14

ELISA and direct Coombs test

Question 15

What is the ELISA test testing for

Answer 15

Antibodies

Question 16

How does the direct Coombs test work

Answer 16

Detects antibodies bound to RBC’s, agglutination assay

Question 17

Type III hypersensitivities are reactions caused by ___formed by ___

Answer 17

Small immune complexes formed by soluble antigens

Question 18

What Ig’s are released in type III hypersensitivity

Answer 18

IgG or IgM

Question 19

What causes small aggregates/complexes

Answer 19

Exposure to antigen or antibody excess

Question 20

SLE is example of what type of hypersensitivity

Answer 20

Type III

Question 21

What happens in sensitization phase of type III hypersensitivities

Answer 21

Initial exposure to antigen resulting in immune complexes that deposit into tissues

Question 22

What happens in effector phase of type III hypersensitivity reactions

Answer 22

Immune complex activation of complement and recruitment of inflammatory cells

Question 23

Immune complexes in type III hypersensitivity reactions accumulate in tissue and cause continual activation of ____ and release of ___ and ____

Answer 23

Complement, neutrophils and ROS

Question 24

Platelet aggregation and possible development of thrombi, hemorrhage, edema and necrosis in tissues could be a result of what type of hypersensitivity reaction

Answer 24

Type III

Question 25

What type of hypersensitivity reaction is Arthus reaction

Answer 25

Type III

Question 26

What causes arthus reaction- localized vasculitis

Answer 26

Sensitization of antigen results in high levels of antibody production leading to antibody excess Upon repeated exposure antibodies form small immune complexes and deposit in vasculature at exposure site

Question 27

What are some examples of arthus reactions- localized vasculitis

Answer 27

Canine blue eye, hypersensitivity pneumonitis, equine RAO

Question 28

What causes systemic vasculitis (serum sickness)

Answer 28

Large dose of foreign serum or in response to some infection—> antigen excess

Question 29

Where do small immune complexes in systemic vasculitis form

Answer 29

Vessel walls

Question 30

Systemic immune complex deposition result in tissue damage and what are 3 common manifestations

Answer 30

Vasculitis, arthritis, glomerulonephritis

Question 31

What vaccine in horses can cause purpura hemorrhagica

Answer 31

Strangles, immune response to bacterial M protein

Question 32

What is a diagnostic test that can be used in type III hypersensitivities

Answer 32

ELISA immunoassays

Question 33

What are some possible treatments for type III hypersensitivities

Answer 33

Corticosteroids, antibiotics, and supportive care (IV, NSAIDS)

Question 34

What cells mediate type IV hypersensitivity reactions

Answer 34

TH1, macrophages, and cTL’s

Question 35

Type IV hypersensitivity reactions are often caused by what complexes

Answer 35

Hapten carrier

Question 36

What happens during sensitization phase of type IV hypersensitivity reaction

Answer 36

Primary immune response

Question 37

What happens during effector phase of type IV hypersensitivity reaction

Answer 37

Activation of memory Th1 cells

Question 38

What cytokines are released by Th1 in type IV effector phase

Answer 38

IFN-y and IL-8

Question 39

Recruitment an activation of macrophages and neutrophils in type IV effector phase result in tissue destruction due to ___ and ___

Answer 39

Lytic enzymes and ROS

Question 40

Prolonged Type IV hypersensitivity reactions can lead to ___formation

Answer 40

Granuloma

Question 41

Turbecule formation is an example of what type of hypersensitivity reaction

Answer 41

Type IV

Question 42

What in vivo testing can be done for TB

Answer 42

Intradermal tuberculin testing

Question 43

What proteins are injected in TB skin test

Answer 43

Tiubuerculin proteins

Question 44

What in vitro testing can be done for TB

Answer 44

IFN-y release assay, measure release by T cells

Question 45

How would you perform IFN-y release assay for TB

Answer 45

Obtain blood, add antigen, centrifuge, remove supernatant, measure IFN-y with ELISA

Question 46

What type of hypersensitivity reaction is contact dermatitis

Answer 46

Type IV

Question 47

What complex forms with contact dermatitis

Answer 47

Hapten that complexes with protein

Question 48

Contact dermatitis is characterized by

Answer 48

Eczematous, blistering reactions

Question 49

What tests can be done for contact dermatitis

Answer 49

patch test, small square impregnated with suspected allergen

Question 50

What indicates a positive patch test

Answer 50

Redness, edema, formation of vesicles