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Flashcards in Lecture 2 Deck (36):
1

What is primary lymphoid tissue 

Site of production for B cells and T cells 

  • Bone marrow and thymus 

2

What is secondary lymphoid tissue 

 

sites where B and T cells become activated by antigen 

  • Lymph nodes
  • Pyers patch
  • Adenoid tonsils 

3

What is lymphoedma

  • Lymphatic obstruction 
  • Inherited 
  • Cancer treatment 
  • Parasitic infections
  • Tissues with lyphodema are at are higher risk of infection

4

Describe the features of the innate immune system 

  • Rapid responce - mins to hrs 
  • The same responce is produced to a many different pathogens 

5

Describe the adaptive immune systems 

  • Slow responce - days
  • Unique responce to each individual pathogen
  • Mediated by T cells and B lymphocytes 
  • Immunological memory 

6

Define acute inflammation 

  • Rapidly cleared by the immune system
  • Lasting immunological memory 

7

Describe latent infection

  • Controlled by the immune system 
  • Periodic episode of pathogen reactivation and replication 

8

Decribe Chronic infection 

  • Immune system fails 
  • On-going pathogen replication 

9

How do the two system act in responce to an infection 

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10

How do the two systems communicate with each other 

  1. Direct communication - Via receptor ligand interactions
  2. Indirect communication - production and secretion of cytokines 

11

Describe the direct contact between the arms of the immund system

Via receptor ligand interactions 

    Examples

  • Peptide: MHC or TCR 
  • PAMP: PRR 

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12

Decribe the indirect contact between the two arms 

synthesis and secrtion of cytokines by activated immune cells or injured tissue cells

13

Give some examples of cytokines 

  • Interferones 
  • TNF 
  • leukoriences 

14

What do virally-infected cells produce

 

Interferons - INF 

15

What is the function of Interferons 

  • Signals neighboring uninfected cells to destroy RNA and reduce proteins synthesis 
  • Signaling neighboring infected cells to undergo Apoptosis 
  • Activates immune cells - natural killer cells 

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16

What are the early innate immune responces 

  • Acute inflammation 
  • Macrophages 
  • Mast cells 
  • NK cells

17

How does the innate immune system recognise and respond to pathogens 

  1. Recognition phase
  2. Activation phase
  3. Effector phase 

18

Describe the Recognition phase 

Pathogens express Pathogen associated Molecular Patterns - PAMPs

  • These are common to many different species of pathogen
  • Innate immune cells express Receptors for these PAMPs
  • Pattern-recognition receptors - PRR 
  • PRR - are found on cell surface and intracellularly - for extra and intracellular pathogens 

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19

Give examples of PAMP:PRRS

  1. Toll-like receptor 4 : Lypopolysaccharide LSP (gram -ve bacteria)
  2. Dectin 1 : B - Glucans (fungi)
  3. Toll like receptor 7 : ssRNA (viruses)

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20

What are all the innate immune cells that are tissue-resinant 

  • Macrophages
  • Mast cells
  • Natural killer cells 
  • Dendritic cells 

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21

How do apoptotic cells get cleared from the body

  • When a cell undergoing apoptosis it releases Eat me signals
  • Binds to engulfment receptors on apoptotic body and is cleared 

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22

Decribe the process of phagocytosis 

  • Apoptotic cell will release eat me signals which will bind to engulfment receptors on phagocyte 
  • Formation of phagocytic cup 
  • The cup will extend around the and pinch off forming a phagosome 
  • Phagosome will fuse with a lysosome inside the macrophage 
  • Formation of  phagolysosome causes lysis its contents
  • Debris are released into the Extra-cellular fluid
  • at the same time cytokins like IL-10 are being released to dampen down any unwanted responces 

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23

What happens when this is injury or infeciton to the tissue 

  1. Early innate immune responces are triggered
  • Macrophages
  • NK cells 
  • mast cell

​    2. Pathogens and infected tissue cells are killed

    3. Production of inflammatory mediators 

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24

What is the difference between macrophages phagocytosing pathogens and tissue cells 

  • Phagocytosing tissue cells - will released anti-inflammatory cytokines - IL-10 
  • phagocytosing Pathogens - will released Pro-inflammatory cytokines  + antigen presentation 

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25

What is contained within the phagolysosome 

  • Lysozyme
  • Hydrolases
  • Proteases 
  • Acidification 

26

Which bacteria can invade phagocytotic killing

  • Salmonella 
  • Staph- aurous 
  • Mycobacteria - TB

27

How do macrophages deal such pathogens 

  • Enhancement of phagocytosis by pro-inflammatory cytokines - e.g IFNy (NK cells)
  • Leads to production of toxic Reactive oxygen and nitrogen species ROS/RNS 
  • Now can present antigen on surface 

28

What is the function of Natural killer cells 

Kill virally infected and tumour cells and ignore normal cells 

29

How can NK cell differentiate between the normal cells and abdnormal cells 

  • Normal cells present MHC Class 1 on their cell surface which allows them to termed normal
  • Where as an infected cell will not present MHC Class one - production of pro-inflammatory mediators

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30

Describe how NK cells kill pathogens and enhance phagocytosis 

  • Virus infectes cell - which will result in altered or absent MHC CLass 1 - This will allow the infected cell to be detected and killed by the NK cells
  • At same time indirect activation of IFNa/b - pro-inflamatory cytokines 
  • Release of IFNy - allows enhancement of macrophages - activation of ROS/RNS 
  • Increased pathogen killing and antigen presentation by macrophage

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31

What are some inflammatory Mediators that are produced during the innate responce 

  • Nitric oxide 
  • pro-inflammatory cytokines - TNFa
  • Prostaglandins/ leukotriens
  • Histamine 

32

What does production of inflammatory mediators cause 

localised aute inflammation

33

What are the clinical features of acute inflammation 

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34

What is the acute phase responce 

  • Changes in concentration of plasma proteins in repsonce to inflammation 
  • This is driven by cytokines produced during localised inflammatory responces
  • Changes due to altered protein synthesis in the liver 

35

What are the acute phase proteins and whats their function 

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36

What is the role of CRP and how is it produced

  • Used as marker for inflammation 
  • Prevents spread of inflammation and prevents systemic inflammation 
  • produced in the liver in responce to production of - IL6 and IL-1b

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