Vet Hypersensitivities

Question 1

How are antibodies formed?

Answer 1

• heavy-chain locus multiple Variable (V) Diversity (D) and Junction (J) segments
• light-chain locus only multiple V and J segments

Question 2

What creates antibody diversity?

Answer 2

Gene-rearrangement of V,D and J segments in pre-B cells

Question 3

What is gene conversion?

Answer 3

• one DNA sequence replaces a homologous sequence (similar sequence)
• overwriting the gene

Question 4

What are hypersensitivities?

Answer 4

There is failure in central and /or peripheral tolerance.
- The immune system reacts against harmless antigens
- Includes autoimmune diseases

Question 5

What are the four types of Hypersensitivity?

Answer 5

• Type 1 (Antibodies against environmental antigens)
• Type 11 (antibodies against cellular antigens)
  -Type 111 (antibodies in immune complexes)
• Type 1V (cellular response to chemicals/ antigens)

Question 6

How do Type 11 Hypersensitivities work?

Answer 6

• antibodies against host cells
• destroy cells using complement pathway

Question 7

What diseases are examples of type 11 hypersensitivities?

Answer 7

• incompatible blood transfusions
• haemolytic disease of the new born
• myasthenia gravis

Question 8

What happens to horses effected by haemolytic disease of the new born (Type 11 Hypersensitivities)

Answer 8

• female antigens encounter in utero red blood cells via leakage through placenta
• mother does not possess specific RBC antigen
• sensitised animals = previous blood transfusions from previous pregnancies
• anti-newborn RBC are produced
• anti- BBC pass into new born via colostrum
• move into new born circulation
• haemolytic disease

Question 9

What are the symptoms for the haemolytic disease of the new born?

Answer 9

• born healthy, foals sicken after suckling
• weakness
• jaundice
• mucus membrane damage
• can lead to death

Question 10

How do type 111 hypersensitivities work?

Answer 10

• caused by reactions against soluble antigens in the serum
• damage where the immune complex deposite

Question 11

What are the symptoms of type 111 hypersensitivities?

Answer 11

• nepheritis
• vasculitis
  -arthritis

Question 12

What type 111 hypersensitivities diseases are there?

Answer 12

• canine adenovirus
• bovine viral diorrhea
• african swine fever
• equine viral arteritis

Question 13

How do Type 1 hypersensitivities work?

Answer 13

• IgE mediated
• Inflamation caused by release of histamine and other molecules
• excessive Th2 envirionment

Question 14

What is Atopy?

Answer 14

Excessive production of IgE

Question 15

What are the symptoms of Type 1 hypersensitvity?

Answer 15

• dependent on route of exposure/ sensation/ dose and species
• itching
• mucous production
• during allergic anaphylaxis (coughing and vomiting)

Question 16

What diseases are caused by type 1 hypersensitivity?

Answer 16

• canine atopic dermatitis
• sweet itch
• allergies to warble fly

Question 17

What are the major cell types involved in type 1 hypersensitivities?

Answer 17

• mast cells
• basophils
• eosinophils

Question 18

What are the major mediators of type 1 hypersensitivity?

Answer 18

• histamine
• leukotrienes and prostaglandins
• cytokines
• chemokines
• seritonin

Question 19

What is the mechanism of type 1 hypersensitivity?

Answer 19

• first exposure to antigen
• antigen activation of Th2 cells and stimulation of IgE class switching in B cells = Production of IgE
• binding of IgE to mast cells
• repeated exposure to allergen = activates mast cell to release mediators
• basophils = also release histimine and can bind to IgE / amplifiying allergic responce by increasing IgE production
• Eosinophils = secrete Th2 cytokines, leukotrienes and prostoglandins

Question 20

What do hypersensitivty vaccines consist of ?

Answer 20

• specific antigens of pathogen
• adjuvant
• trace amounts of molecules relating to production

Question 21

What reactions can be dominant during type 1V hypersensitivities?

Answer 21

• CD8- T cell dominant (destruction of host cells, direct damge to host cells)
• CD4 T cell dominant (accumulation of T cells, indirect damage to host cells)

Question 22

What mechanisum is completed during type 1V hypersensitivities?

Answer 22

• Antigen is injected into subcontanious tissue and processed by local antigen-presenting cells
• Th1 effector cell releases cytokines which act on vascular endothelium
• Recruitment of phagocytes and plasma to site of antigen injection causes visible lesion

Question 23

What diseases are type 1V hypersensitivities?

Answer 23

• allergic contact dermititis
• insect bit hypersenstivity

Question 24

What are Haptens (type 1V hypersensitivity)

Answer 24

A small molecule which, when combined with a larger carrier such as a protein, can elicit an immune response. (alter protein shape/fold)

Question 25

What is the reaction of Allergic contact dermatitis?

Answer 25

• inflamation/ damaged caused
• chemicals bind to skin protiens
• skin protiens taken up by lagerhan cells
• langerhan cells move to lymphnode or interact with Th1 cell
• secrete Il-12/ IL-23 activate Th1 cells and/or Th17 cells
• T cells move to skin to respond against skin cells