Exam 3: Hypersensitivity Type IV

Question 1

what type of immune response in type IV hypersensitivity

Answer 1

cellular immune response

Question 2

what is the main cell involved in type IV hypersensitivity

Answer 2

T cells

Question 3

type IV hypersensitivity characteristics

Answer 3

injected antigen

antigen presenting cells

T cells

tuberculin

Question 4

what is tuberculin

Answer 4

inflammatory response in the skin of an animal affected with tuberculosis following intradermal injection of tuberculin

Question 5

how long does it take for type IV hypersensitivity to appear

Answer 5

delayed hypersensitivity

inflammation in 12-24 hours

increased intensity of inflammation 24-72 hours

Question 6

what causes false negative in tuberculin

Answer 6

animals with advanced tuberculosis (IgG)

test at early stage of infection

Question 7

types of tuberculin tests in cattle

Answer 7

single intradermal

comparative

short thermal

stormont

Question 8

single intradermal
use
advantages
disadvantages

Answer 8

use - routine testing

advantages - simple

disadvantages - prone to false negatives, poor sensitivity

Question 9

comparative
use
advantages
disadvangates

Answer 9

use - when avian TB or Johne disease is prevalent

advantages - more specific than SID

disadvantages - more complex than SID

Question 10

short thermal
use
advantages
disadvantages

Answer 10

use - use in postpartum animals and in infected animals

advantages - high efficiency

disadvantages - time consuming, risk for anaphylaxis

Question 11

Stormont
use
advantages
disadvantages

Answer 11

use - use in postpartum animals and in advanced cases

advantages - very sensitive and accurate

disadvantages - three visits required, may sensitize an animal

Question 12

different kinds of skin tests for tuberculin

Answer 12

Johnin = Mycobacterium avium var paratuberculosis

Brucella abortus

Mallein = Burkholderia mallei

Histoplasmin = Histoplasmosis

Coccidoidin = Coccidioidomycosis

Question 13

allergic contact dermatitis

Answer 13

if reactive chemicals are painted onto skin, they may bind to skin proteins, and the resulting complexes are processed by Langerhans cells in the dermis

Question 14

what can cause allergic contact dermatitis

Answer 14

poison ivy

haptens - chrome, nickel, resin, latex

Question 15

Atopic dermatitis vs Allergic contact dermatitis

pathogenesis

Answer 15

Atopic dermatitis - type I hypersensitivity

Allergic contact dermatitis - type IV hypersensitivity

Question 16

Atopic dermatitis vs Allergic contact dermatitis

clinical signs

Answer 16

Atopic dermatitis - hyperemia, urticaria, pruritis

Allergic contact dermatitis - hyperemia, vasiculation, alopecia, erythema

Question 17

Atopic dermatitis vs Allergic contact dermatitis

distrubution

Answer 17

Atopic dermatitis - face, nose, eyes, feet, perineum

Allergic contact dermatitis - hairless areas, usually ventral abdomen and feet

Question 18

Atopic dermatitis vs Allergic contact dermatitis

major allergens

Answer 18

Atopic dermatitis - foods, pollens, fleas, inhaled allergens

Allergic contact dermatitis - reactive chemicals, dyes in contact with skin

Question 19

Atopic dermatitis vs Allergic contact dermatitis

diagnosis

Answer 19

Atopic dermatitis - intradermal testing, immediate response

Allergic contact dermatitis - delayed response on patch testing

Question 20

Atopic dermatitis vs Allergic contact dermatitis

pathology

Answer 20

Atopic dermatitis - eosinophilic infiltration, edema

Allergic contact dermatitis - mononuclear cell infiltration, vesiculation

Question 21

Atopic dermatitis vs Allergic contact dermatitis

treatment

Answer 21

Atopic dermatitis - steroids, antihistamines, hyposensitization

Allergic contact dermatitis - steroids

Question 22

measurement of cell proliferation

Answer 22

the measurement of cell proliferation by detecting the uptake of tritiated thymidine

Question 23

measurement of cell proliferation - what stimulates the cells to divide

Answer 23

cells are stimulated to divide by specific antigen or a mitogen

Question 24

measurement of cell proliferation - where is thymidine incorporated

Answer 24

the thymidine is incorporates into the DNA of the dividing cells

Question 25

measurement of cell proliferation - how is uptake measured

Answer 25

the uptake is simply measured by the radioactivity of the cells

Question 26

measurement of cell death

Answer 26

the measurement of cell death by detecting the release of chromium-51 by dying cells

Question 27

measurement of cell death - what triggers release of chromium-51

Answer 27

this release may be triggered by cytotoxic T cells or NK cells

Question 28

IFN-y production - Enzyme Linked Immunosorbent Assay

Answer 28

the release of IFN-y by peripheral blood lymphocytes following exposure to tuberculin or to purified mycobacterial antigens

Question 29

what can IFN-y production - Enzyme Linked Immunosorbent Assay be used for

Answer 29

this technique can be used for the diagnosis of tuberculosis in cattle and deer

Question 30

in IFN-y production - Enzyme Linked Immunosorbent Assay, what is added to the blood and how long is it incubated for

Answer 30

tuberculin PPD is added to blood, and the mixture is incubated for 24-48 hours

Question 31

in IFN-y production - Enzyme Linked Immunosorbent Assay, what is removed and what are they looking for

Answer 31

the plasma is then removed and assayed for any interferon produced

Question 32

ELISpot = Enzyme Linked Immunospot steps

Answer 32

1. antibody against cytokine added (IFN) 2. lymphoid cells added and incubate 3. cytokines secreted and bind to capture antibody 4. cells washed off 5. labelled antiglobulin followed by substrate added 6. bound cytokine detected using enzyme labeled antiglobulin

Question 33

IFN-y production - Enzyme Linked Immunosorbent Assay Steps

Answer 33

1. antigen added to blood lymphocytes 2. incubate 3. cytokines secreted 4. centrifuge 5. remove supernatant 6. measure cytokine such as IFN-y using ELISA

Question 34

measurement of cell death steps

Answer 34

1. target cells 2. target cells take up chromium-51 3. cytotoxic cells added 4. incubate 5. killed cells release chromium-51 6. count radioactivity

Question 35

measurement of cell proliferation steps

Answer 35

1. lymphocytes 2. antigen or mitogen added 3. radioactive thymidine 4. dividing cells take up H3-thymidine 5. centrifuge and remove unbound thymidine 6. count radioactivity