CSIM 1.14 - Innate and Aquired Immunity

Question 1

What is the first-line defence to pathogens?

Answer 1

Barrier mechanisms - (skin/gut/eyes/lungs)

Question 2

Name four mechanical barriers acting as first-line defence against invading pathogens?

Answer 2

Tight junctions
Mucus
Tears
Air flow

Question 3

Name five chemical barriers acting as first-line defence against invading pathogens?

Answer 3

Low pH (stomach)
Fatty acids (skin)
Pepsin (stomach)
Antibacterial peptides
Lysozyme (tears)

Question 4

Name a microbiological barrier acting as first-line defence against invading pathogens?

Answer 4

Normal flora (gut and skin)

Question 5

If compromised how are barrier mechanisms backed-up?

Answer 5

Pro-Inflammatory signals (TGF-beta and IL-6) leads to up-regulation of TH-17 cells

Question 6

What is the second-line of defence against invading pathogens?

Answer 6

Innate Immunity

Question 7

What is the innate immune system composed of?

Answer 7

Cells - phagocytes

Proteins - complement

Question 8

Name the seven types of phagocytes and where they are found within the body?

Answer 8

Macrophages - tissues
Kupfer cells - liver
Monocytes - blood
Alveolar macrophage - lung
Langerhan cells - skin
Microglia - CNS
Neutrophils - blood and UN-healthy tissue

Question 9

How do phagocytes discriminate ‘self’ vs ‘non-self’?

Answer 9

Pathogens have PAMP
Phagocytes have PRR
(PAMP binds to PRR and pathogen is phagocytosed)

Question 10

Name four receptors macrophages express for pathogen recognition?

Answer 10

Mannose
LPS
Toll-like receptor 4 (TLR-4)
Glucan

Question 11

How do phagocytes produce superoxide anions and what happens to this molecule?

Answer 11

Respiratory bursts:
O2 converted to O2- (via NADPH oxidase)
02- converted to H2O2 (via Superoxide dismutase)
H202 converted to hydroclorate ions and hydroxyl radicals (via Peroxidase enzymes)

Question 12

Name five ways in which phagosomes are destroyed?

Answer 12

Acidification (bactericidal/bacteriostatic)
Toxic Oxygen-derived
Toxic Nitrogen
Lysozyme (phagolysosome)
Competitors (lactoferrin/VitB12 binding protein)

Question 13

Describe Toll-like receptors?

Answer 13

Recognise sets of patterns NOT found on vertebrae, activation induces pro-inflammatory cytokines

Question 14

Name the five cytokines released by TLR activation and state their site of actions?

Answer 14

IL-1 (M and keratinocyte) acts on liver/lymphocytes
IL-6 (M/D) acts on liver/lymphocytes
IL-8 (M/D) acts on phagocytes (recruits nuetrophils)
TNF-a (M/D) acts on vasular endothelium
Il-12 (M/D) acts on naive T-cells

Question 15

Name the two cell adhesion molecules up-regulated by cytokine release?

Answer 15

E + P selectin

Question 16

Describe the main characteristics of innate immunity?

Answer 16

Rapid response (0-4 hours)
Non-specific (receptor specificity inherited in genome)
No memory

Question 17

Name a condition in which NADPH oxidase is deficient?

Answer 17

Chronic granulomatous disease

Question 18

Describe the main characteristics of adaptive immunity?

Answer 18

Very specific (one Ag = one antibody)
Delayed onset at FIRST encounter
Memory