Lecture 28: Type II-IV Hypersensativities

Question 1

type II (cytotoxic) hypersensitivity occurs through the production of ____or____ that binds to specific allergens located on______

Answer 1

IgM, IgG, cells

Question 2

2 phases of cytotoxic hypersensitivity

Answer 2

sensitization phase: exposure to antigen leads to IgM or IgG production
Effector phase: re-exposure to antigen allows allergen specific IgM or IgG to bind, causing immune mediated damage or blocks normal function of the cell

Question 3

antibody dependent cellular cytotoxicity

Answer 3

NK cells or macrophages killing antibody coated target cells

Question 4

complement mediated lysis

Answer 4

activation of classical complement pathway to form membrane attack complexes to kill target cells

Question 5

primary immune mediated hemolytic anemia (IMHA) is considered…

Answer 5

idiopathic/autoimmune

Question 6

secondary IMHA is caused by….

Answer 6

an immunologic response against non-self antigens that have adsorbed or motified normal RBC membranes
- antibodies bind to antigens on RBCs resulting in lysis
- causes include various infectios agents or drugs (antibiotics)

Question 7

Transfusion reactions are mediated by antibodies that….

Answer 7

bind and lyse transfused RBCs
manifestations result from intravascular hemolysis of transfused RBCs

Question 8

what can you do to prevent blood transfusion reactions

Answer 8

perform blood typing and cross-matching tests

Question 9

neonatal isoerythrolysis

Answer 9

hemolytic disease of newborns
- destruction of newborn RBCs, foals and kittens mostly

Question 10

neonatal isoerythrolysis is mediated by ______that bind and lyse neonatal RBCs

Answer 10

mismatched blood group maternal antibodies

Question 11

Direct Coomb’s test detects…

Answer 11

antibodies bound to RBCs
agglutintion test

Question 12

type III (immune complex) hypersensitivity is caused by what

Answer 12

small immune complexes formed by soluble antigens binding to IgG or IgM

Question 13

two phases of type III immune complex hypersensitivity

Answer 13

Sensitization and effector phases, occur in continuum

Question 14

sensitization phase of Type III

Answer 14

initial exposure to antigen, results in immune complex formation that deposit into tissues

Question 15

effector phase of Type III

Answer 15

immune complex activation of complement & recruitment of inflammatory cells to site of deposition
* inflammation results in increased permeability

Question 16

immune complexes accumulate in tissues and cause damage due to…

Answer 16

• continual activation of complement
• neutrophil release of tissue damaging enzymes and reactive oxygen intermediates
• platelet aggregation and possible development of thrombi, hemorrhage, edema and necrosis

Question 17

arthrus recactions =

Answer 17

localized vasculitis

Question 18

sensitization to antigen results in high levels of______production, leading to _____excess

Answer 18

Antibody, antibody

Question 19

upon repeated exposure to antigen at same site, _____antibodies form small immune complexes that deposit in the _______ or at the _______

Answer 19

IgG, Vasculature, exposure site

Question 20

can occur in response to large dose of foreign serum or infections (antigen excess)

Answer 20

systemic vasculitis (serum sickness)

antitoxins, antivenins, bacterial/viral infections

Question 21

sensitization of horses vaccinated or infected with S.equi may develop a type ____ hypersensitivity reaction (Purpura Hemorrhagia)

Answer 21

Type III

Question 22

Purpura Hemorrhagica

Answer 22

• horses vaccinated or infected w/ S.equi develop type III hypersensitivity
• immune response occurs against bacterial M protein
• upon exposure to large amount of antigen, small immune complexes form that deposit in the vasculature
• causes tissue damage, fever, depression, anorexia, vasculitis, mucousal hemorrhages

Question 23

testing for type III hypersensitivity

Answer 23

Immunoassays

Question 24

type IV (delayed) hypersensitivity is mediated by ____ cells and ______

Answer 24

Th1 and macrophages

Question 25

hapten-carrier complex

Answer 25

allergen (microbial component, chemical metal, or drug) that complexes with proteins in the skin

Question 26

Type IV hypersensitivity reactions take ______hours to develop

Answer 26

24-72

Question 27

in type IV hypersensitivity, initial exposure is often through _________contact w/ the allergen

Answer 27

direct

Question 28

processing and presentation of hapten carrier complex occurs by

Answer 28

APCs

Question 29

during the sensitization phase of type IV hypersensitivities, activation and differentiation of helper T cells into TH1 cells causes the development of....?

Answer 29

memory (sensitized) TH1 cells | can also involve activation of CD8 Tcells

Question 30

what occurs during the effector phase in Type IV hypersen.

Answer 30

APC activation of memory (sensitized) TH1 cells upon subsequent exposure to antigen

Question 31

release of TH1 cytokines and chemokines to recruit and activate _______and_____ results in ________

Answer 31

macrophages+neutrophils, Inflammation * INF-y and IL-8

Question 32

during effector phase of Type IV hypersen., the recuritment/activation of macrophages+neutrophils results in tissue destruction due to the release of....

Answer 32

lytic enzymes and ROIs

Question 33

prolonged type IV reactions can lead to....

Answer 33

granuloma formulation - can occur in some persistent bacterial infections

Question 34

Diagnostic testing for TB

Answer 34

* in vivo testing-intradermal tuberculin rxn * in vitro testing-INF-y to release