SDL hypersensitivity

Question 1

What is the pathology of bovine tuberculosis?

Answer 1

• infection via inhalation or ingestion (mycobacterium bovis)
• granular formation due to immune response
• causes necrosis of infected cells within granulomas
• dissemination as bacteria breaks out of granuloma and infects other areas

Question 2

What form of hypersensitivity reaction is measured in the SICCT (single ID comparative cervical tuberculin test)?

Answer 2

Type IV delayed-type hypersensitvity

Question 3

What is canine atopic dermatitis? (cAD)

Answer 3

genetically predisposed inflammatory and pruritic allergic skin disease associated with IgE antibodies most commonly to environmental allergens

Question 4

What allergens can lead to cAD?

Answer 4

house dust mites
pollens
mould spores in environment and food

Question 5

What is the immune response to atopic dermatitis?

Answer 5

Sensitisation phase:
- as dogs are growing, if they are genetically predisposed and subject to appropriate exposure they develop disease
- non-allergenic dogs may produce non-allergenic antibodies or fail to respond (anergy)

Provocation phase:
- once allergic, Langerhans cells are coated in antigen-specific IgE and can induce T-cell proliferation readily
- the Th2 bias results in a cytokine environment that favours the production of IgE and T-cells produce IL-31 which leads to pruritus and other cytokines causing inflammation

Question 6

Explain the immune response to flea allergic dermatitis (FAD)

Answer 6

initially a type I hypersensitivity reaction
This wanes over time and type IV responses become more important