Lecture 28 - Innate Immunity I

Question 1

Components of the innate immune system
1)
2)
3)

Answer 1

1) Barriers
2) Secretions
3) Cells

Question 2

Barrier components of the innate immune system
1)
2)
3)
4)
5)

Answer 2

1) Epithelial cells can present antigen
2) Skin has a slightly acidic pH
3) Fatty acids are on skin
4) Epithelial cells in stomach secrete acid
5) Mucocilliary elevator pushes mucus into stomach

Question 3

Role of surfactant
1)
2)
3)

Answer 3

1) Maintains surface tension in alveoli, to stop them from collapsing from laminar flow
2) Flowing air decreases air pressure, which would collapse alveoli without surfactant
3) This prevents collapsed alveoli forming a good place for bacteria to grow

Question 4

Chromic granulomatous disease
1)
2)

Answer 4

1) Defect in Neutrophil NADPH oxidase enzyme

2) Neutrophils can’t kill phagocytosed bacteria

Question 5

Mechanical innate defences
1)
2)
3)
4)

Answer 5

1) Epithelial cells joined by tight junctions
2) Longitudinal flow of air or fluid in gut, skin, lungs
3) Movement of mucus by cilia
4) Tears, lysozyme

Question 6

Chemical defences of the skin
1)
2)
3)
4)

Answer 6

1) Fatty acids
2) Beta-defensins
3) Lamellar bodies
4) Cathelicidin

Question 7

Chemical defences of the gut
1)
2)
3)
4)
5)

Answer 7

1) Low pH
2) Enzymes
3) Alpha-defensins
4) Lecticidins
5) Cathelicidin

Question 8

Chemical defences of the lungs
1)
2)
3)

Answer 8

1) Surfactant
2) Alpha-defensins
3) Cathelicidin

Question 9

Eyes, nose, oral cavity chemical defences 
1)
2)
3)
4)
5)

Answer 9

1) Tears
2) Nasal cilia
3) Lysozyme in tears and saliva
4) Histadins
5) Beta-defensins

Question 10

Neutrophils
1)
2)
3)
4)

Answer 10

1) Abundant in blood
2) Increased production in bone marrow in response to infection
3) Very potent at phagocytosing
4) First immune cells to respond

Question 11

Neutrophil rolling and extravasation
1)
2)
3)

Answer 11

1) Rolling adhesion with E-selecin
2) Tight adhesion initiated by CXCL-8 binding to IL-8, binding by ICAM-1 to LFA-1
3) Diapedesis and migration towards IL-8 source

Question 12

How do neutrophils kill phagocytosed bacteria?

Answer 12

ROS and nitrogen radical generation by NADPH oxidase

Question 13

Neutrophil NETS

Answer 13

Opsonise bacteria for phagocytosis

Made of DNA

Question 14

How long do neutrophils live for?

Answer 14

Normally around 8 hours

Question 15

Eosinophils
1)
2)
3)
4)

Answer 15

1) Contain arginine-rich basic granules
2) Small numbers in blood, majority reside in tissues
3) Parasites coated with antibodies or complement lead to degranulation
4) Important role in allergic diseases

Question 16

Eosinophil granule types
1)
2)

Answer 16

1) Microbicidal (radicals, toxic proteins)

2) Immunomodulatory (leukotrienes, prostaglandins, cytokines)

Question 17

Basophils
1)
2)
3)
4)

Answer 17

1) Apparently similar role to eosinophils
2) Recruited to site of IgE-mediated allergic reactions
3) Release of histamine, IL-4, IL-13
4) Involved in Th2 differentiation

Question 18

Monocytes and macrophages
1)
2)
3)
4)
5)
6)

Answer 18

1) Unlike neutrophils, can present antigens
2) Relatively long-lived
3) Phagocytic
4) Orchestrate immune responses
5) Clear cell debris, dead cells (scavenger role)
6) Increase microbicidal activity in presence of IFNg

Question 19

Difference in macrophage phagocytosis in inflammatory and non-inflammatory conditions
1)
2)

Answer 19

1) Inflammatory - Increased superoxide burst for killing microbes, decreased proteolysis, increased MHC presentation
2) Non-inflammatory - Highly degradative phagosome, no MHC presentation

Question 20

Mast cells 
1)
2)
3)
4)
5)

Answer 20

1) A specific type of macrophage
2) Found in connective tissues
3) Increases vascular permeability (critical role in leukocyte recruitment)
4) Releases histamine, IL-4, IL-13
5) Has no innate ability to recognise antigens. Sequesters IgE on surface to use as a receptor

Question 21

How are mast cells degranulated?

Answer 21

When 2 or more IgE bound to IgeR bind to antigen, crosslink

Question 22

Cardinal signs of inflammation
1) 
2) 
3) 
4) 
5)

Answer 22

1) Heat
2) Pain
3) Swelling
4) Redness
5) Loss of function