review of innate immunity

Question 1

what has an innate immune response?

Answer 1

everything

Question 2

why do we need an innate immune response?

Answer 2

adaptive immune response ( antibodies and T cells) is too slow to protect us from new pathogens

Question 3

how long does it take for an antibody response to kick in?

Answer 3

around 5 days

Question 4

why do we need an innate response?

Answer 4

provides first line defence to keep infection under control until adaptive immunity kicks in- AB + T cells otherwise response would be too slow. ensures survival of individual until other response

Question 5

what response is required to resolve an infection

Answer 5

both innate and adaptive

Question 6

what are they key differences between adaptive and innate immunity

Answer 6

adaptive- involves very specific recognition of infectious agents, ie antigen
innate has no specific antigen recognition
innate immunity involves recognition of broadly conserved features of different classes of pathogens (PAMPS)

Question 7

what does PAMP stand for

Answer 7

Pathogen-associated molecular pattern molecules (PAMPs)

Question 8

what is a PAMP

Answer 8

• molecules present only on pathogens and not on host cells, they’re essential for the survival of pathogens.

9PAMPs) are derived from microorganisms and recognized by pattern recognition receptor (PRR)-bearing cells of the innate immune system as well as many epithelial cells.

invariant structures shared by entire class of pathogens, things pathogens cannot avoid having for their life cycle. these are enough to alert your immune system

Question 9

State examples of PAMPs for G -ve, G+ve, bacteria, and viruses?

Answer 9

• Gram-negative bacteria; lipopolysaccharides (LPSs) found in outer membrane- endotoxin
• Gram-positive bacteria; teichoic acid, lipoteichoic acid, peptidoglycan found in outer membrane
• Bacterial flagellin
• Abnormal protein glycosylation
• Abnormal nucleic acids - viruses

Question 10

for every pamp, there has to be a receptor, what is this receptor called?

Answer 10

pattern recognition receptor- PRR

Question 11

what is a PRR

Answer 11

host factor that specifically recognise a particular type of PAMP. they are invariant

Question 12

what is special about PRR genes?

Answer 12

they are germ line encoded.. meaning these genes dont rearrange, theyre the same in every cell

-These receptors evolved to recognize conserved products of microbial metabolism produced by microbial pathogens,

Question 13

briefly, what are the three classes of functional PRRs?

Answer 13

extracellular, intracellular, secreted

Question 14

what is an extracellular PRR?

Answer 14

recognise PAMP outside the cell and trigger a coordinated response to the pathogen

Question 15

what is the intracellular PRR?

Answer 15

• cytoplsmic
• recognise PAMP inside cell and act to coordinate response to pathogen

Question 16

what is secreted PRR?

Answer 16

they go off into the bloodstream and act to tag circulating pathogens for elimination ie compliment system

Question 17

what are the 5 components to the innate immune system?

Answer 17

they all trigger each other

1. The inflammatory response
2. Phagocytes
   Monocytes/granulocytes/neutrophils
3. Complement
4. Cytokines, chemokines and anti-microbial
   peptides (AMPs)
5. Natural Killer cells

Question 18

what is the inflammatory response?

Answer 18

A generic defence mechanism whose purpose is to localize and eliminate injurious agents and to remove damaged tissue components

Question 19

effect of infalmmatory response?

Answer 19

• Enhanced permeability and extravasation
  
  • Permeability, so cells can get to site of infection
  • Extravasation = cells from blood to tissue
• Neutrophil recruitment
• Enhanced cell adhesion
• Enhance clotting

Question 20

what is the infalmmatory response triggered by?

Answer 20

by the release of pro-inflammatory cytokines and chemokines at the site of infection

Question 21

what is a chemokine

Answer 21

chemo attractants, signals at high conc where pathogen is and therefore low concs eveyrhwere else and that conc grad is what stimulates neutrophils etc to go to source

Question 22

what are the three different types of phagocytes

Answer 22

• monocytes
  -granulocytes
  -neutrophils

Question 23

what are the three different types of phagocytes

Answer 23

• monocytes
  -granulocytes
  -neutrophils

Question 24

what are the three types of phagocytes that can carry out phagocytosis?

Answer 24

Dendritic cells, macrophages and neutrophils

• Considered as professional phagocytes

Question 25

state the 3 distinct roles of macrophages and dendritic cells in immunity

Answer 25

1. phagocytosis, the material is destroyed in lysosomes
   2.triggering inflammatory response
   3.Peptides from broken down pathogens can be presented through MHC and promote the development or recall of an adaptive T cell response (more for D cell)

Question 26

what is MHC

Answer 26

The major histocompatibility complex (MHC) isa series of genes that code for cell surface proteins that control the adaptive immune response.

Question 27

what are 5 ways in which phagocytes recognise pathogens

Answer 27

1. By detecting phosphatidylserine on exterior membrane
   surface -cells undergoing apoptosis
2. By detecting “atypical sugars” (e.g. mannose, fucose, beta-glucan) on cell surfaces
3. By Scavenger receptors → receptors that are non-self
4. By “passive sampling’
5. By detecting complement proteins bound to the pathogen surface

Question 28

what is a scavenger receptor

Answer 28

receptor that recognise non self

Question 29

what is a scavenger receptor

Answer 29

receptor that recognise non selft

Question 30

two broad ways in which phagocytes recognise and eat pathogens

Answer 30

-cell mediated
-passive sampling

Question 31

the main aim of the complement system?

Answer 31

• number of soluble proteins made and secreted by the liver whos job is to bind to pathogens and decorate for destruction