2. Innate Immunity

Question 1

How is the innate immune system activated?

Answer 1

Tissue injury

Microbes breeching a barrier

Question 2

Name 3 receptors that initiate the innate immune response

Answer 2

Toll-like receptors
RIG-1 type
NOD-like receptor

Question 3

Name a receptor that can induce phagocytosis

Answer 3

Dectin-1

Question 4

Describe the process of phagocytosis

Answer 4

Microbes bind to receptors on neutrophils and macrophages
Engulfed into phagosome
Phagosome fuses with the lysosome

Question 5

What substances are used to kill microbes in phagocytosis?

Answer 5

NO
Reactive Oxygen Species
Lysosomal proteases

Question 6

What is chronic granulomatous disease?

Answer 6

X-linked disease

Defect in NADPH oxidase results in dysfunctional phagocytosis

Question 7

What does chronic granulomatous disease result in?

Answer 7

Frequent bacterial and fungal infections

Formation of granulomas

Question 8

How is chronic granulomatous disease diagnosed?

Answer 8

DHR assay

Question 9

What is the function of NADPH oxidase?

Answer 9

Produces reactive oxygen species

Question 10

What mediators do macrophages release when they detect a microbe?

Answer 10

IL-1
TNF
IL-8

Question 11

What result does the release of IL-1 and TNF have?

Answer 11

Causes endothelial cells to express selectin which results in rolling adhesion

Question 12

What result does the release of IL-8 have?

Answer 12

Stimulates integrin on leukocyte, causes tight adhesion

Acts as a chemoattractant to guide leukocytes to the site of the infection

Question 13

What are the functions of cytokines?

Answer 13

1. Danger signal causing WBCs to be drawn out of the blood towards the site of damage
2. Autocrine and paracrine to increase cytokine production
3. Causes endothelial cells to increase adhesion molecules
4. Increase permeability
5. Causes fever
6. Acute phase protein production by liver

Question 14

What cells release chemokines?

Answer 14

Damaged and immune cells

Question 15

What are the functions of chemokines?

Answer 15

Chemoattractant

Increase expression of adhesion molecules on immune cells

Question 16

What are the classes of lipids involved in innate immunity?

Answer 16

Prostaglandins
Leukotrienes
PAF

Question 17

What cells produce prostaglandins?

Answer 17

Endothelial cells

Question 18

What are the functions of prostaglandins and leukotrienes?

Answer 18

Vasodilators and constrictors

Question 19

What cells produce leukotrienes?

Answer 19

Immune cells

Question 20

What cells produce PAF?

Answer 20

Endothelial and immune cells

Question 21

What is the function of PAF?

Answer 21

Increase permeability

Question 22

What processes lead to the resolution of acute inflammation?

Answer 22

Short life of neutrophils and inflammatory mediators
Macrophages become anti-inflammatory
Inhibitory cytokines limit inflammation
Growth factors act on fibroblasts to increase repair
Production of anti-inflammatory lipoxins, resolving and protectins

Question 23

Name 2 inhibitory cytokines

Answer 23

IL-10

TGF-b

Question 24

Name a growth factor which acts on fibroblasts

Answer 24

FGF

Question 25

What cells are antigen presenters

Answer 25

Dendritic cells Macrophages B cell

Question 26

What cells express MHC-II?

Answer 26

APCs

Question 27

Where does MHC-II start?

Answer 27

ER Transported to the endoscope after phagocytosis Combines with antigen peptides and moves to the cell surface

Question 28

What type of T cell interacts with MHC-II?

Answer 28

CD4+

Question 29

What cells express MHC-I?

Answer 29

All nucleated cells

Question 30

What type of T cells interact with MHC-I?

Answer 30

CD8+

Question 31

What type of antigens is MHC-I used for?

Answer 31

Self-peptides Cancer Viruses Intracellular bacteria

Question 32

What type of antigens is MHC-II used for?

Answer 32

Extracellular pathogens

Question 33

What factor can cause a NK cell to increase killing?

Answer 33

A reduction in MHC-I levels

Question 34

What do NK cells use to kill cells?

Answer 34

Granzyme | Perforin

Question 35

Where are the genes for the MHC found?

Answer 35

Chromosome 8

Question 36

What are the variable MHC genes for class 1?

Answer 36

HLA-A, B or C

Question 37

What are the variable MHC genes for class 2?

Answer 37

HLA-DP, DQ or DR

Question 38

What are the functions of the complement system?

Answer 38

1. c3a and c5a promote inflammation 2. c3b promotes opsonisation and phagocytosis 3. c6-9 form the membrane attack complex

Question 39

What are the 3 complement pathways?

Answer 39

Classic Alternative Lectin

Question 40

How does the complement cascade promote inflammation?

Answer 40

Chemoattractants for neutrophils and monocytes Stimulate release of inflammatory mediators Increase vasodilation and permeability

Question 41

How does the complement cascade increase opsonisation and phagocytosis?

Answer 41

c3b deposited on surface of microbes | Recognised by Complement Receptor of phagocytes

Question 42

Which bacteria is MAC especially effective in?

Answer 42

Neisseria

Question 43

What does a c3 deficiency result in?

Answer 43

Frequent pyogenic infections | More severe in adults

Question 44

What does a C2-4 deficiency result in?

Answer 44

Autoimmune diseases eg. SLE

Question 45

What does a C5-9 deficiency result in?

Answer 45

Recurrent neisseria infections

Question 46

What does a c1 inhibitor deficiency result in?

Answer 46

inability to switch off inflammation | Heriditary angioedema