Immuno 1: Hypersensitivity and allergy: part 3

Question 1

Give examples of type 1 hypersensitivty mediated inflammation

Answer 1

Anaphylaxis, urticaria, angioedema TYPE 1- IgE

Question 2

Give examples of type 2 mediated inflammation

Answer 2

Idiopathic/chronic urticaria TYPE II- IgG

Question 3

Give examples of confitions involving mixe inflammaiton. Which hypersensitivt yreactions are these mediated by

Answer 3

Asthma, rhinitis, eczema Mesiated by type I hypersensitivity (IgE mediated) type IV hypersensitivity (chronic inflammation)

Question 4

What is rewquired for expression of allergic disease

Answer 4

Development of sensitisation to allergens instead of tolerance (primary response - usually in early life) Further allergen exposure to produce disease (memory response - any time after sensitisation)

Question 5

Outline sensitisation of atopic airway disease

Answer 5

Dendritic cell samples the airway. Presents antigen to naive T cell T cell decides whether to be tolerant to the antigen (in which case it becomes Treg) or auto-immune disease (Th1) or an allergic response (Th2). If Th2 route was chosen, then Th2 cells will then proliferate and produce IL-4 and IL-13, which makes B cell produce IgE, not IgG antibodies IgE which is specific to the antigen will bind to plasma cells and cause IgE production IgE bind to mast cells.

Question 6

Outline what happens in subsequent exposure, following sensitisation in atopic disease

Answer 6

Same process with dendritic cell But the antigen will be presented to Th2 memory cells from the sensitisation stage Which will then cause more IL4 and IL13 to make more IgE. IL5 released by Th2 to recruit eosinophils and activate them. Eosinophils then release inflammatory mediators IgE bound to mast cells undergoes crosslinking with the antigen Causes degranulation of mast cells and release of inflammatory mediators

Question 7

Eosinophils make up what proportion of blood leukocytes

Answer 7

0-5% of blood leukocytes

Question 8

T/F most eosinophils present in tissues

Answer 8

T…. Present in blood, most reside in tissues

Question 9

What is the nucleus of an eosinophil like

Answer 9

Nucleus - two lobes

Question 10

What is contained in the granules of eosinophils

Answer 10

Toxic proteins…. the grnules arfe LARGE

Question 11

What is an effect of eosinophil activation

Answer 11

TISSUE DAMAGE

Question 12

T/F mast cells are tissue resident cells

Answer 12

T

Question 13

How are mast cells avtivated

Answer 13

IgE receptors on cell surface

Question 14

What happens upon IE cross linking to mast cells

Answer 14

MEDIATOR RELEASE 1. Pre-formed: -Histamines -Cytokines -Toxic proteins 2. Newly synthesised -leukotrienes -prostaglandings

Question 15

Which disease are neutorhils important in

Answer 15

virus induced asthma, severe asthma, atopic eczema

Question 16

What proportion of blood leukocytes are neutrophils

Answer 16

55-70% of blood leukocytes

Question 17

Neutrophils are aka

Answer 17

Polymorphonuclear cells (PMNs)

Question 18

What is the nucleus of a neutrophil like

Answer 18

Nuecleus several lobes

Question 19

What is contained within the granules of neutrophils what else do neutrophils synthesise

Answer 19

digestive enzymes Also synthesize oxidant radicals cytokines leukotrienes

Question 20

Outline the pathology of asthma

Answer 20

Acute airway inflammation Mast cell activation and degranulation –> release of prestored mediators (e.g. histamine, leading to airway wall oedema) –> release of newly synthesised mediators (prostaglandins and leuktrienes) LEADS TO: Acute airway narrowing (airway smooth muscle contraction)