3: Overview of the Innate Immune System

Question 1

Which cell links the innate and adaptive immune systems?

Answer 1

Dendritic cell

Question 2

Describe the time taken for the innate immune system to respond to a pathogen.

Answer 2

Rapid (mins-hrs)

Question 3

The innate immune system exhibits the ___ response to many ___ pathogens.

Answer 3

same , different

Question 4

Describe the time taken for the adaptive immune system to respond to a pathogen.

Answer 4

Slow (days)

Question 5

The adaptive immune system has a ___ response to each pathogen it encounters.

Answer 5

unique

Question 6

Which cells mediate the adaptive immune system?

Answer 6

T and B lymphocutes

Question 7

The adaptive immune system is responsible for immunological ____.

Answer 7

memory

Question 8

Direct contact relies on receptor:____ interaction.

Answer 8

ligand

Question 9

Which cells may bind to an immune cell by receptor:ligand interaction?

Answer 9

Pathogen
Another immune cell
Tissue cell

Question 10

Injured tissue cells / activated immune cells produce ____ which bind to and activate other cells indirectly.

Answer 10

cytokines

Question 11

What is the first phase of an innate immune response to a pathogen?

Answer 11

Recognition phase

Question 12

Pathogens express ____ on their surfaces.

Answer 12

PAMPs (pathogen-associated molecular patterns)

Question 13

Innate immune cells express ___ on their surfaces.

Answer 13

PRRs (pattern-recognition receptors)

Question 14

The PRR ‘Toll-like receptor 4’ binds to which PAMP in which type of organism?

Answer 14

Lipopolysaccharide (LPS) in Gram -ve bacteria

Question 15

The PRR ‘Dectin 1’ binds to which PAMP in which type of organism?

Answer 15

Beta glucans in fungi`

Question 16

What are the next two phases of an innate immune response to a pathogen?

Answer 16

Activation phase

Effector phase

Question 17

The activation and effector phases of an innate immune response involve…

Answer 17

Acute inflammation and pathogen killing

Question 18

What are the resident innate immune cells in the skin?

Answer 18

Macrophages, mast cells, NK cells and dendritic cells

Question 19

Briefly outline the clearance of apoptotic cells by resident macrophages

Answer 19

1. Apoptotic cells express an ‘eat-me’ signal which attracts and activates macrophages
2. Macrophage phagocytoses the apoptotic cell
3. Secretion of anti-inflammatory cytokine IL-10 to prevent tissue damage

Question 20

Which anti-inflammatory cytokine is released to limit tissue damage following phagocytosis of apoptotic cells?

Answer 20

IL-10

Question 21

Which molecules activate tissue-resident immune cells when the physical barrier is breached?

Answer 21

PAMPs (from the pathogen)
Danger signals (from the tissue damage)

Question 22

What are the three outcomes of innate immune system activation?

Answer 22

Pathogen killed
Infected cells killed
Release of pro-inflammatory mediators

Question 23

Which pro-inflammatory mediator ‘superactivates’ macrophages?

Answer 23

Interferon gamma

Question 24

When interferon gamma ‘superactivates’ a macrophage, what happens?

Answer 24

1. Increased production of reactive oxygen and nitrogen species (toxic)
2. Increased antigen presentation capability

Question 25

What happens when mast cells are activated?

Answer 25

Degranulation

Question 26

What molecules are released when a mast cell degranulates?

Answer 26

Pro-inflammatory mediators

Question 27

What happens when NK cells are activated?

Answer 27

They specifically kill infected cells / abnormal cells

Question 28

What molecules are released after an NK cell specifically kills its target?

Answer 28

Pro-inflammatory mediators

Question 29

Name two means by which macrophages, mast cells and NK cells kill pathogens.

Answer 29

1. Phagocytosis 2. Reactive oxygen species 3. Anti-microbial peptides

Question 30

Name two cytokines other than interferon gamma which are important in systemic effects following detection of a pathogen.

Answer 30

TNF(alpha), IL-1, IL-6

Question 31

Name two systemic effects caused by the pro-inflammatory cytokines TNF(alpha), IL-1 and IL-6.

Answer 31

Fever Increased neutrophil production (leukocytosis) Acute Phase Response

Question 32

What is the acute phase response?

Answer 32

Change in protein concentrations as a response to inflammation

Question 33

What drives the acute phase response?

Answer 33

Pro-inflammatory cytokines

Question 34

What is a major acute phase protein used as a marker for inflammation?

Answer 34

C Reactive Protein

Question 35

C Reactive Protein is a marker for inflammation in what response?

Answer 35

Acute phase response

Question 36

Name two effects that C Reactive Protein has on the innate immune system.

Answer 36

1. Enhances phagocytosis | 2. Activates complement system