Innate cell responses to infection

Question 1

Where are unactivated monocytes located in the body?

Answer 1

Circulating in blood

Question 2

What occurs when monocytes are activated?

Answer 2

They migrate to tissues and differentiate into macrophages

Question 3

What type of macrophage is in the lungs?

Answer 3

Alveolar macrophage

Question 4

What type of macrophage is in the brain?

Answer 4

microglial cells

Question 5

Where are histiocytes located, and what type of innate immune cell lineage are they from?

Answer 5

Type of macrophage located in connective tissue

Question 6

Where are kupffer cells located, and what type of innate immune cell lineage are they from?

Answer 6

Type of macrophage located in liver

Question 7

What type of macrophages are in bone?

Answer 7

Osteoclasts

Question 8

What are the 2 mechanisms of a macrophage responding to infection?

Answer 8

Phagocytosis, becoming an APC

Question 9

What 2 things happen to the pathogen in phagocytosis?

Answer 9

Ingestion then destruction

Question 10

Where on the macrophage membrane does a pathogen attach?

Answer 10

Pseudopodia: membrane evagination (area folded inwards to form a pit)

Question 11

After pathogen ingestion what vesicle is formed?

Answer 11

Phagosome

Question 12

What cellular vesicle does the phagosome fuse with to digest the phagosomal content?

Answer 12

lysosome

Question 13

What pathway is used to present bacterial antigens?

Answer 13

Exogenous pathway

Question 14

How is the pathogen processed in the exogenous pathway?

Answer 14

extracellular pathogen is acquired, brought into cell then digested into antigenic fragments (peptides)

Question 15

Which MHC class is used to present bacterial antigens?

Answer 15

MHC II

Question 16

Which type of T cell is a bacterial antigen presented to?

Answer 16

Helper T cell

Question 17

Which MHC class is used to present a viral antigen?

Answer 17

MHC I

Question 18

Which type of T cell is a viral antigen presented to?

Answer 18

Cytotoxic T cell

Question 19

Which pathway is used to present viral antigens?

Answer 19

endogenous

Question 20

How is the pathogen processed in the endogenous pathway?

Answer 20

Intracellular pathogen is degraded in the cytoplasm to antigenic fragments (peptides)

Question 21

Where do immature dendritic cells take up pathogens?

Answer 21

Infected peripheral tissues

Question 22

Where do mature dendritic cells migrate to?

Answer 22

Lymph nodes

Question 23

Why are dendritic cells better APCs than macrophages?

Answer 23

DCs have lower degradation potential, so antigens are preserved and can be presented for a longer time, so can activate more T cells

Question 24

What are 2 characteristic features of the granulocytic cell lineage?

Answer 24

Granular cytoplasm, multi-lobed nucleus

Question 25

What are the 2 main function of neutrophils?

Answer 25

phagocytosis, releasing antimicrobial factors

Question 26

What antimicrobial factors are released by neutrophils?

Answer 26

lactoferrin, Human alpha-Defensins

Question 27

What stimulates migration of neutrophils to sites of infection and inflammation?

Answer 27

Chemotaxis with IL-8

Question 28

What is chemotaxis?

Answer 28

Directed movement of cells in a gradient of chemoattractant (chemotactic factor)

Question 29

What is the chemotactic factor for neutrophils?

Answer 29

IL-8

Question 30

What percentage of circulating granulocytes is neutrophils?

Answer 30

95%

Question 31

What substance is neutrophils the major component of?

Answer 31

Pus

Question 32

Do neutrophils have a long life span?

Answer 32

No, they are short-lived

Question 33

When eosinophils, basophils and mast cells kill parasites, how do they recognise the target parasite?

Answer 33

IgE binds to parasite

Question 34

What process causes release of histamines from eosinophils, basophils and mast cells?

Answer 34

degranulation

Question 35

Where are mast cells found in the body?

Answer 35

Loose connective tissue

Question 36

What substance is released during allergic reactions to trigger inflammation?

Answer 36

cytokines

Question 37

What is the main function of Natural Killer cells?

Answer 37

recognise and destroy abnormal cells

Question 37

What are 2 types of abnormal cells targeted by NK cells?

Answer 37

malignant cells, viral cells

Question 38

How do NK cells recognise abnormal cells?

Answer 38

NK cells recognise lack of MHC I ligands expressed, as presence inhibits NK cells in normal cells

Question 39

What is a characteristic feature of NK cellular granules?

Answer 39

Cytotoxic