*Introduction to Innate and Adaptive Immunity

Question 1

what are the 4 main tasks that the immune system must perform?

Answer 1

1. Immunological recognition
2. Immune effector function
3. Immune regulation
4. Immunological memory

Question 2

what are the 2 types of immune cells?

Answer 2

• innate immune cells
• adaptive immune cells

Question 3

what of the 4 tasks is isolated to innate immune cells?

Answer 3

1. immune recognition

Question 4

what of the 4 tasks are found in both innate and adaptive immune cells?

Answer 4

2. immune effector mechanisms
3. immune regulation

Question 5

what of the 4 tasks is isolated to adaptive immune cells?

Answer 5

4. immunological memory

Question 6

what are the bodies 3 lines of defence?

Answer 6

1. External physical barriers
2. Innate (non-specific) immunity
3. Adaptive (specific) immunity

Question 7

what are the 3 forms of the first line of defense against pathogens?

Answer 7

• skin
• mucous membranes
• Normal microbiota (Commensal bacteria)

Question 8

what makes the skin a first line of defence against pathogens?

Answer 8

• Strength from collagen
• Sweat containing salt, lysozyme and sebum

Question 9

what makes the mucous membranes a first line of defence against pathogens?

Answer 9

• Epithelium and connective tissue
• Goblet cells make mucous
• Pathogens find it hard to penetrate the mucous
• Cilia that sweep the mucous and trapped pathogens / particles along

Question 10

what makes the normal microbiota a first line of defence against pathogens?

Answer 10

• Compete with potential pathogens
• Consume nutrients
• Change pH
• Secrete antimicrobial substances

Question 11

what is the second line of defence?

Answer 11

innate immunity

Question 12

what are the 3 main features of innate immunity?

Answer 12

• fast (responds within minutes to hours of infection)
• non-specific (doesn’t differentiate between pathogens)
• generic (same response everytime)

Question 13

what is phagocytosis? what 3 cells mainly carry it out?

Answer 13

“cell eating”
- Macrophages (initial sensing of pathogens)
- Neutrophils (clearing up pathogens)
- Dendritic cells (activation of T cells)

Question 14

where are macrophages found?

Answer 14

Fixed (resident in particular tissues e.g. liver) or wandering (move through tissues) macrophages

Question 15

what is the role of a macrophage?

Answer 15

Recognition of pathogen and elimination of pathogens and/or removal dead/damaged cells by phagocytosis and signalling other immune cells for support.

Question 16

what are the 5 steps of a macrophage killing a pathogen?

Answer 16

1. recognition + attachment
2. ingestion
3. killing
4. degradation
5. exocytosis

Question 17

explain regonition + attachment by macrophages

Answer 17

Bacterium becomes attached to membrane evaginations called pseudopodia

Question 18

explain ingestion by macrophages

Answer 18

bacteria is ingested, forming phagosome

Question 19

explain killing by macrophages

Answer 19

phagosome fuses with lysosome

Question 20

explain degradation by macrophages

Answer 20

lysosomal enzymes digest captured material

Question 21

explain exocytosis by macrophages

Answer 21

digestion product are released from cell

Question 22

name the 8 fixed macrophages and where they are found

Answer 22

• alveolar macrophages/dust cells : pulmonary alveolus
• histiocytes : connective tissue
• kupffer cells : liver
• microglia : neuronal tissue
• epithelioid cells : granulomas
• osteoclasts : bone
• sinusoidal lining cells : spleen
• mesangial cells : kidney

Question 23

where are neutrophils found?

Answer 23

Produced and released from bone marrow in response to infection (leukocytosis - a clinical indicator)

Question 24

neutrophils circulate in blood for _____ prior to migrating into tissue (extravasation)

Answer 24

neutrophils circulate in blood for 7-10hr prior to migrating into tissue (extravasation)

Question 25

what is the lifespan of neutrophils?

Answer 25

2-3 days

Question 26

what is the role of neutrophils?

Answer 26

One of first cell types to arrive at site of infection, attracted by chemotaxic factors secreted by macrophages

Question 27

what is a neutrophil characterised by?

Answer 27

a multi-lobed nucleus

Question 28

true or false: the neutrophils structure is granulated

Answer 28

true

Question 29

what are the 2 types of granules?

Answer 29

- primary granules - secondary granules

Question 30

what are the function of primary granules?

Answer 30

primary granules are more focused on intracellular destruction

Question 31

what are the function of secondary granules?

Answer 31

econdary granules have more extracellular functions.

Question 32

what 3 primary granules are found in neutrophils?

Answer 32

- peroxidase - lysozyme - hydrolytic enzymes

Question 33

what 3 secondary granules are found in neutrophils?

Answer 33

- collagenase - lactoferrin - lysozyme

Question 34

what is the role of dendritic cells?

Answer 34

- Potent antigen presenting cells. - Main function of bone marrow-derived dendritic cells is to activate T helper cells.

Question 35

where are dendritic cells found?

Answer 35

found in most tissues

Question 36

where can dendritic cells be derived from?

Answer 36

Can be derived from circulating monocytes (also precursor cells for macrophages)

Question 37

in what 3 ways do phagocytes recognise pathogens?

Answer 37

- Pathogen Associated Molecular Patterns (PAMPS) - Opsonization of pathogen by antibody : Fc receptor ligation (future lecture) - NK (Natural Killer) cells recognise a lack of cell  surface markers such as MHC class I

Question 38

up to slide 16