Lect 2 - Innate Immunity

Question 1

differentiate innate vs adaptive

Answer 1

innate is early
relies on molecules that differentiate things form our bodies

we all have the same receptors and molecules

Question 2

what are the significances of adaptive

Answer 2

it can remember past, and gives us a faster response, also allows for vaccines

Question 3

what are the components of the innate immune system

Answer 3

barriers - stop infection
cells - alert the system
circulating proteins - seek out different and mark them for the rest of IS

Question 4

understand how barriers help protect us, provide some examples

Answer 4

mechanical - tight junctions stop things getting in, movement by cillia

chemical - fatty acid, low pH

microbiological - flora

Question 5

describe what happens once the skin breaks

Answer 5

break skin, things get in
antimicrobial protein and peptide
setup system of activation as well as trying to heal

Question 6

how does phalysosome kill

Answer 6

phagolysosomes have enzymes that make bleach to kill

Question 7

what are some types of proinflammatory cytokines

Answer 7

TNF-α (tumour necrosis factor)
• IL-1 (interleukin-1) 
• IL-12 
• Type 1 interferons (interferon alpha and interferon beta) 
 –induce antiviral state, increase MHC I

Question 8

how do we recognise pathogens

Answer 8

PAMP - protein, n acid or lipid. they look different to normal.

Question 9

compare the different steps in response by innate, early induced, and adaptive

Answer 9

innate: infection ->recognition by non-specific ->removal of infectious agent

early induced: infection->recognition of molecular pattern->inflammation and effector cells->removal of infectious agent

adaptive immune: infection->transport to lymphoid organs->recognition by B and T-cell->clonal expansion and differentiation of effector cell->removal of infectious agent

Question 10

how does normal flora protect us from disease

Answer 10

1. Competing with invaders for space and nutrients
2. Producing compounds (bacteriocins) which kill other bacteria
3. Lowering the pH so that other bacteria can’t grow

Question 11

what are the cells of the innate immune system

Answer 11

1. macrophages - monocytes
2. neutrophils - granulocyte
3. mast cells - unknown
4. eosinophilic - granulocyte
5. dendritic cells -granulocyte
6. basophils

Question 12

how do macrophages work

Answer 12

recognise microorganisms through their surface receptors
phagocytosis then occurs
phagosome then merge with lysosome

they also release cytokines to signal others

Question 13

how do neutrophils work

Answer 13

neutrophils live in the blood, not present in normal tissue

they phagocytose and remove pathogen, without the assistance of adaptive immune system

Question 14

if neutrophils is only found in circulation, how does it get to tissues

Answer 14

macrophages release chemical as a result of  
the pathogen, this activates 
receptors on the 
neutrophils and the cell 
wall to cause the 
neutrophil to leave the 
circulation and go to the 
inflamed tissue

Question 15

how does phagolysosome kill

Answer 15

by releasing bleach

Question 16

what are the dendritic cells

Answer 16

there are many types of dendritic cells

derived from the bone marrow, and live for a long time

their main function is to capture antigen and present if to lymph nodes

They act as messengers between the innate and the adaptive immune systems

activates T-cells and T-cell differentiation

Question 17

eosinophils and mast cells

Answer 17

they release histamine

eosinophils important for protection against helminths

Question 18

how does the innate immune system respond in inflammation

Answer 18

macrophages, sends for effector molecule via cytokine that start blood clot, more fluid, leading to vascular dilation

this gets neutrophils, eosinophils and lymphocytes

there are also lipid mediators such as prostaglandins and clotting factor

Question 19

how do we recognise pathogens

Answer 19

pattern recognition receptors recognise pathogen-associated molecular patterns (PAMPs)

molecules have patterns on there surfaces

PRR fit with a distinct pattern that’s on the pathogen

the outcome depends on
effector cells used
receptor involved

Question 20

describe toll like receptors and what they do?

Answer 20

TLR recognises microbial molecular patterns
it then sets off a signal cascade that also facilitates the initiation of acquired immune responses due to proinflammatory cytokines

Question 21

what are MCH I

Answer 21

they are present on all cells, they bind to KIRs and stop NK cells from degranulating.

Question 22

how does NK cells kill, and the 2 ways that it does it

Answer 22

NK cells kill by touching with the infected cell, and releasing granule which will either make holes causing lysis, or it will result in apotosis

Question 23

what do NLRs do

Answer 23

NOD-like receptors, cytosolic receptors that recognise and alert cells to invasion.

activated by things such as peptidoglycan, RNA, toxins, and flagellum in cytosol.

Question 24

how does the innate system deal with viruses

Answer 24

Various viral components
are recognised by PAMPs
in the virally infected cell

Trigger production of
interferons to try to
prevent spread of viral
infection to adjacent cells

Adjacent cells can put
special measures in place
that interfere with viral
replication

Question 25

what are the 3 complement pathways

Answer 25

classical - antigen/antibody

lectin - lectin bind to carbohydrate on pathogen surfaces

alternate - pathogen surfaces

Question 26

what the result of the complement system

Answer 26

peptide mediator of inflammation phagocyte recruitment

opsonization of pathogens

killing pathogens via lysis

Question 27

what is the complement pathway

Answer 27

the complement system is a major mechanism by which pathogen recognition is converted into effective defense against initial infection

3 pathways
classic which is triggered directly by pathogen or indirectly by antibody binding to the pathogen surface

lectin contrasts the classical complement pathway, it does not recognize antibody bound to its target. The lectin pathway starts with mannose-binding lectin or ficolin binding to certain sugars

alternate - provides amplification loop