Innate immune system

Question 1

Innate immune system

Answer 1

• Humoral

- Cellular

Question 2

Professional phagocytes

Answer 2

• Monocytes
• Macrophages
• Neutrophils
• Dendritic cells
• Mast cells

Question 3

Pattern recognition receptors

Answer 3

Three categories of PRRs can be engaged during phagocytosis:

PRRs that mediate phagocytosis
PRRs that initiate inflammatory signal transduction
PRRs that can do both

Question 4

Mannose receptor

Answer 4

• It is on phagocytes
• It mediates phagocytosis, it does not initiate inflammatory signal transduction
• Used by mycobacterium tuberculosis

Question 5

Mycobacterium tuberculosis

Answer 5

• It is taken up by a mannose receptor
• It does not trigger an inflammatory response
• It sits inside an early endosome
• Produces proteins that prevent fusion with a lysosome

Question 6

Normal phagocytosis pathway

Answer 6

• Bacteria taken up into an endosome, phagosome
• Phagosome fuses with a lysosome, phagolysosome
• Enzymes in the phagolysosome break down the bacteria

Question 7

Macrophages structure

Answer 7

• They have PRRs, mannose receptors

- Toll like receptors, TLRs

Question 8

Toll like receptors

Answer 8

• A type of pattern recognition receptor and recognize molecules that are shared by pathogens, called the pathogen associated molecular patterns, PAMPs
• They recognise bacteria in vesicles
• Transmembrane proteins
• A cytoplasmic and extracellular portion
• They will transduce a signal through the cell to increase transcription of certain cytokines (increase levels of transcription factor NFKB)

Question 9

PAMPs

Answer 9

• Molecules associated with groups of pathogens that are recognised by cells of the innate immune system
• They are recognised by toll like receptors
• Eg. flagella, LPS, lipoteichoic acid and peptidoglycan

Question 10

TLR vs NLR

Answer 10

TLR, membrane bound

NLR, cytoplasm bound