Innate Immune Protection

Question 1

What are the characteristics of the innate immune response?

Answer 1

first line of defence
born with it
very fast
responds the same every time
induces adaptive immunity

Question 2

What are the physical barriers of the innate immune response?

Answer 2

skin, gi tract, respiratory tract, mucosal epithelia

Question 3

What are the 3 components of the innate immune system?

Answer 3

Physical/anatomical barriers
secreted compounds
cellular components

Question 4

How does the skin protect against E.coli?

Answer 4

It produces antimicrobial compounds

Question 5

What are the defence mechanisms of the respiratory tract?

Answer 5

tight so difficult to penetrate
has cilia to move bacteria
mucus can trap bacteria

Question 6

How does the GI tract defend against bacteria?

Answer 6

peristalsis to move bacteria

hydrochloric acid and low pH kill bacteria

Question 7

How do the eyes protect against bacteria?

Answer 7

By blinking and producing tears

tears, sweat and saliva contain lysoszymes which destroy bacteria walls

Question 8

What is microbial competition?

Answer 8

The body already has lots of healthy bacteria which compete with the pathogenic bacteria for nutrients

Question 9

What are PAMPs

Answer 9

They are pathogen associated molecular patterns which are present on microorganisms but not the hosts

Question 10

What 4 things allow you to recognise bacteria?

Answer 10

Pattern recognition receptors (PRR)
Collectins (serum)
Toll like receptors (membrane)
Nod like receptors (cytoplasm)

Question 11

What are collectins?

Answer 11

Made up of a collagen and lectin region
binds to sugar molecules on the surface of pathogen and affects the sugar spacing which determines whether PRR binding can occur and signal to the rest of the immune system

Question 12

Features of toll like receptors?

Answer 12

10 of them
TLR3 - recognise RNA virus
TLR5 - recognise flagellin (in flagellum)
TLR9 - recognise unmethylated DNA (all human DNA is myelinated
They cover the cell surface

Question 13

Features of nod like receptors?

Answer 13

Sit in cytoplasm
recognise gram positive and gram negative bacteria
NOD 1 = sense y-glutamyl diaminopimelic acid
NOD 2 = sense muramyl dipeptide

Question 14

What are compliments?

Answer 14

A series of proteins which operate via a cascade

uses protein C3 activated by C3 convertase

Question 15

What are the two molecules involved in phagocytosis?

Answer 15

Macrophage

Neutrophil

Question 16

What are the 7 steps of phagocytosis?

Answer 16

1) chemotaxis and adherence of microbe to phagocyte
2) ingestion of microbe by phagocyte
3) formation of a phagosome
4) Fusion of the phagosome with a lysosome to form a phagolysosome
5) digestion of ingested microbe by enzymes
6) formation of residual body containing indigestible material
7) discharge of waste material

Question 17

How does the phagolysosome?

Answer 17

Production of reactive oxygen intermediates and by the production of reactive nitrogen intermediates

Question 18

What is the respiratory burst?

Answer 18

following phagocytosis there is an increase in oxygen uptake
oxygen is reduced by NADPH oxidase to form hydroxyl radicals and hypochlorite
reactive oxygen intermediates cause DNA damage and alterations in bacterial membranes

Question 19

How does nitrogen intermediates cause death?

Answer 19

Produces DNA damage and alterations in bacterial membranes

Question 20

What are cytokines?

Answer 20

They are proteins and intracellular messengers

Question 21

What are chemokines?

Answer 21

promotes inflammation by enabling cells to adhere to the surface of blood vessels and migrate to infected tissue

Question 22

What do type 1 interferons do?

Answer 22

They activated NK cells, they kill virally infected cells and tumour cells, they are responsive to TNFa and IL-12 and they produce IFNy

Question 23

What are critical cytokines?

Answer 23

Activates macrophages and upregulates MHC molecules together with IL-12. stimulates differentiation of CD4 th1 cells

Question 24

How the innate immunity moves to the adaptive immune response?

Answer 24

Naive T-cells activated by 2 signals
1 - antigen presenting cell to the t cell from small fragments as well as MHC
2 - Innate immune response generates second signal by recognition of pathogens by PRR’s
T-cells then become the effector t-cell
Upon recognition of pathogen by a TLR, cytokines can be produced and effect the t-cell

Question 25

What can antigen presenting cells?

Answer 25

Macrophages
B-cells
dendritic cells

Question 26

What are dendritic cells?

Answer 26

They mostly exist as immature cells
they display lots of PRR’s so if he PRR’s bind with a pathogen the dendritic cell will mature
activates naïve t-cell as its an antigen presenting cell

Question 27

What does C3b do?

Answer 27

Opsonises pathogens