Cells of the Innate Immune System

Question 1

What is the unfolded protein response?

Answer 1

Stress response to ER protein accumulation, causing apoptosis and translation inhibition.

Question 2

How has Mtb evolved to live with 90% hosts?

Answer 2

Recruits rab14 to prevent phagosome maturation, therefore no MHCI expression. However, the macrophage still knows it is infected so produces a granuloma via IFNy and TNF.

Question 3

What is a granuloma?

Answer 3

Core of infected macrophages surrounded by uninflected macrophages, normally multinucleate Langhans giant cells.

Question 4

Describe the grouping of chemokines and what it is dependent on.

Answer 4

~50 different chemokines split into four groups, dependent on the spacing on Nter Cysteines.

Question 5

What are chemokine receptors and why are some of them a disadvantage?

Answer 5

G-protein coupled receptors; CCR5 and CXCR4 are also major HIV-1 coreceptors.

Question 6

What is a sentinel cell?

Answer 6

Cells in the first line of defence e.g. Macrophages

Question 7

What receptors enable the high phagocytic ability of macrophages?

Answer 7

Scavenger, mannose and complement receptors.

Question 8

What is the difference between M1 and M2 macrophages?

Answer 8

M1 act earlier and are proinflammatory, M2 act later and remodel tissue as well as being anti-inflammatory.

Question 9

What type of macrophage do cancers recruit?

Answer 9

M2, they aid tumour progression via angiogenesis, growth factor secretion, and metastasis.

Question 10

Name four neutrophil functions.

Answer 10

Phagocytosis, release antimicrobials, produce ROI, release DNA nets, produce cytokines, successively bind tighter to capillary endothelial cells and then migrate along chemoattractant tails immobilised in glycoproteins.

Question 11

What are the role of NK cytoplasmic granules?

Answer 11

Insert into the plasma membrane of targets and induce apoptosis.

Question 12

Can NK cells remove viruses?

Answer 12

No, only stabilise.

Question 13

Name a stimulatory and inhibitory receptor of NK cells.

Answer 13

Stimulatory - natural cytotoxicity receptors

Inhibitory - killer Ig-like receptors

Question 14

What is the structure of mast cells?

Answer 14

Monolobed nucleus and election dense granules.

Question 15

Where are mast cells, basophils, and eosinophils found?

Answer 15

Mast cells in the tissues, and basophils/eosinophils circulating in the blood.

Question 16

What type of T cell response do mast cell derived cytokines promote?

Answer 16

Th2

Question 17

What are five responses of interferon?

Answer 17

Apoptosis of neighbouring cells, inhibition of protein synthesis via R/P1 kinase, degradation of RNA via RNaseL, increased MHCI expression, and NK cell activation.