Immunology - Tut 2

Question 1

What is hypersensitivity?

Answer 1

Adaptive immunity serves function of host defence but the immune response is capable of causing tissue damage

Question 2

What are the different types of hypersensitivity?

Answer 2

Type 1 = IgE mediated hypersensitivity Type 2 = IgG-mediated cytotoxic hypersensitivity Type 3 = Immune complex-mediated hypersensitivity Type 4 = Cell-mediated hypersensitivity

Question 3

What is nebulized albuterol?

Answer 3

is a bronchiole dilator which is used in asthma puffers

Question 4

What is asthma?

Answer 4

Asthma is a condition caused by the chronic inflammation of the small airways in the lungs - leads to swelling & increased mucus production within the conducting pathways

Question 5

What are the airways more narrow in asthmatics? why and where can this be dangerous to the person?

Answer 5

Asthmatics have narrower airways due to the chronic inflammation is dangerous when asthmatics are exposure to situations which may cause their airways to constrict = bronchioconstriction Exposures; - dry and cold air - contact with pollen or other allergens - illness - stress

Question 6

Why brochiole constriction dangerous in people with asthma?

Answer 6

due to chronic inflammation & further constriction causes difficulty to move air in and out of the lungs the decreased air flow can range from mild to life-threatening

Question 7

What percentage of the population are affected by type 1 hypersensitivity?

Answer 7

~20% of the population in the western world have it. - about 50% of population generate IgE response to airborne allergen but after repeated exposure ~20% develop clinical symptoms - genetic is a key component

Question 8

What are the main cells types involved in type 1 hypersensitivity?

Answer 8

IgE and Mast cells (mast cells release cytokines)

Question 9

What are the different stages of the allergic reaction process?

Answer 9

1. Sensitisation 2. Activation 3. Effector

Question 10

Describe Sensitisation (Allergic Reaction Process).

Answer 10

• IgE antibodies are produced in response to allergic stimulus & binds to receptors on mast cells - a limited number of small proteins cause allergy (<1μg/year) - person who has IgE antibodies & restimulation causes allergic reaction

Question 11

How and where is IgE produced?

Answer 11

IgE is produced by the plasma cells in the lymph nodes & at sites of allergic reaction. Is localised to the tissues & there are low levels present in the serum

Question 12

How does IgE elicit an immune response?

Answer 12

IgE forms a crosslink with the antigen through the FcεR1 which causes the release of chemical mediators by the mast cell = allergic reaction

Question 13

Which antigens & routes of antigen presentation favour IgE production?

Answer 13

1. Presentig antigen at very low dose , across the mucosal surface = activation of the Th2 over Th1 cells 2. Th2 cells produce cytokines which are required for IgE production