Immunology

Question 1

What is innate immunity

Answer 1

Instinctive, non-specific, does not depend on lymphocytes and are present from birth

Question 2

What is adaptive immunity

Answer 2

Specific ‘acquired’ or ‘learned’ immunity, requires lymphocytes and antibodies

Question 3

What is serum

Answer 3

Plasma without clotting factors and fibrinogen

Question 4

What is Complement-C

Answer 4

Group of about 20 serum proteins secreted by the liver that need to be activated to be functional, they are only activated as part of an immune response

Question 5

What are the modes of action of complement-c

Answer 5

• direct lysis
• attract more leukocyte to site of infection
• coat invading organisms

Question 6

Give the 5 classes of antibodies

Answer 6

Ig’s are glycoproteins 
IgG (IgG1-4)
IgA (IgA1 and 2)
IgM
IgD
IgE

Question 7

What is the most predominant Ig in human serum

Answer 7

70-75%

IgG

Question 8

Which Ig requires a J chain

Answer 8

IgM

Mainly found in blood - cannot cross endothelium

Question 9

Which Ig is predominant in mucous secretions

Answer 9

IgA

Called secretory IgA (slgA) -held together by J chain and secretory component

Question 10

Steps of anaphylaxis

Answer 10

1) first exposure (sensitisation)

2) subsequent exposure

Question 11

Explain sensitisation

Answer 11

• first bee sting
• antigen is phagocytosed by a dendritic cell
• antigen presenting dendritic cell presents antigen to activated T-lymphocytes
• Activated T-lymphocyte release cytokines which cause B cells to produce IgE antibodies
• IgE antibodies bind to mast cells and basophils which then release their granules

Question 12

Explain subsequent exposure

Answer 12

• bee stings again
• mast cells and basophils which already have IgE antibodies attached will then bind to the antigens and release pro inflammatory molecules such as histamine, tryptase

Question 13

What does histamine do

Answer 13

• smooth muscle contraction in bronchi and GI tract so tougher to get air and food through
• blood vessel dilation and increased vascular permeability so increased in blood diameter and increase in blood flow which causes hypotension, swelling and itchy skin

Question 14

What does tryptase do

Answer 14

• tryptase is a protease that breaks down proteins and causes tissue injury
• mast cells and basophils make proteins such as cytokines (e.g IL-4 and IL-13 which signal B-cells to make IgE antibodies, tumour necrosis factor alpha and leukotrienes)
• leukotrienes e.g LTB4 and LTC4 attract neutrophils, mast cells and eosinophils

Question 15

What is a biphasic anaphylactic reaction

Answer 15

When symptoms of an anaphylactic shock occurs again hours later

Question 16

What is a protracted anaphylactic reaction

Answer 16

• when anaphylactic symptoms last for days

Question 17

How does adrenaline treat symptoms of anaphylaxis

Answer 17

• blood vessel constriction (increase in peripheral vascular resistance, increased blood pressure and coronary perfusion via alpha1-adrenoceptors)
• increases heart contractility(positive ionotropic) and heart rate (chronotropic effects) through stimulation of beta1-adrenoceptors to prevent cardiovascular collapse
• relaxes smooth muscle that line the bronchi through beta2-adrenoreceptors, helping the airways to open up and reducing oedema