Lecture 28 - Innate Immunity I Flashcards Preview

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Flashcards in Lecture 28 - Innate Immunity I Deck (22):
1

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

1) Barriers
2) Secretions
3) Cells

2

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

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

3

Role of surfactant
1)
2)
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

4

Chromic granulomatous disease
1)
2)

1) Defect in Neutrophil NADPH oxidase enzyme
2) Neutrophils can't kill phagocytosed bacteria

5

Mechanical innate defences
1)
2)
3)
4)

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

6

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

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

7

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

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

8

Chemical defences of the lungs
1)
2)
3)

1) Surfactant
2) Alpha-defensins
3) Cathelicidin

9

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

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

10

Neutrophils
1)
2)
3)
4)

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

11

Neutrophil rolling and extravasation
1)
2)
3)

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

12

How do neutrophils kill phagocytosed bacteria?

ROS and nitrogen radical generation by NADPH oxidase

13

Neutrophil NETS

Opsonise bacteria for phagocytosis
Made of DNA

14

How long do neutrophils live for?

Normally around 8 hours

15

Eosinophils
1)
2)
3)
4)

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

16

Eosinophil granule types
1)
2)

1) Microbicidal (radicals, toxic proteins)
2) Immunomodulatory (leukotrienes, prostaglandins, cytokines)

17

Basophils
1)
2)
3)
4)

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

18

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

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

19

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

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

20

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

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

21

How are mast cells degranulated?

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

22

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

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