Lecture 6 Flashcards

(44 cards)

1
Q

Give 2 examples of cell-adhesion interactions that bring T cell and APC together

A

LFA-1 binding ICAM-1
CD2 binding CD58 (LFA-3)

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2
Q

What do low affinity LFA-1/ICAM-1 interactions facilitate?

A

TCR recognition of a peptide antigen on APC in the context of MHC

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3
Q

Naive T cell possesses an IL-2 receptor, but only expresses __ and __ chains on its surface.

A

𝛾 and β chains

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4
Q

What does CD28-dependent co-stimulation of activated T cell lead to?

A

expression of IL-2 receptor α chain, resulting in a receptor with high affinity for IL-2

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5
Q

What happens when CTLA-4 binds B7 molecules?

A

It delivers an inhibitory signal to activated T cells

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6
Q

How do cytotoxic T cells induce cell death?

A

(i) Through death receptors e.g. engagement of the Fas death receptor on its surface
(ii) Through secretion of IFN𝛾 & TNF, which can facilitate killing of the cell
(iii) Through release of perforin & granzymes, which activate caspases to induce apoptosis

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7
Q

Stimulation of APC through CD40 increases __ and __ , which both co-stimulate __ .

A

B7 and 4-1BBL
naive CD8+ T cell

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8
Q

Th1 cells are defined by production of which cytokines?

A

IFN𝛾 and TNFα

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9
Q

What cytokine drives differentiation into Th1?

A

IL-12

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10
Q

Th2 cells are defined by production of which cytokines?

A

IL-4, IL-5 and IL-33

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11
Q

Th2 immunity is important against __

A

Helminth parasites

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12
Q

Which T helper cell subset promotes the production of mucus?

A

Th2

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13
Q

How does IFN𝛾 affect macrophages?

A

It drives them towards a proinflammatory state (M1 phenotype)

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14
Q

What cytokines do Th17 cells produce?

A

IL-17 and IL-22

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15
Q

What two subsets of T helper cells are important inflammatory mediators in Crohn’s disease?

A

Th1 and Th17

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16
Q

Th17 cells are important for the immune response against…

A

extracellular bacteria (because they increase AMP production and neutrophil chemotaxis)

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17
Q

What cytokine do T follicular helper cells produce?

A

IL-21

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18
Q

How do Tfh cells help B cells?

A
  • Help B cell differentiation & proliferation
  • Boost Ab production, affinity maturation & isotype switching
19
Q

What cytokines are produced by Tregs, and are they pro- or anti-inflammatory?

A

IL-10 and TGF-β
Anti-inflammatory

20
Q

What cytokine drives differentiation into Tfh cell?

21
Q

CD4+ T cell subsets can cross-regulate each other’s differentiation through…

A

through the cytokines that they produce

22
Q

How does IFN-𝛾 affect proliferation of Th cell subsets?

A

IFN-𝛾 promotes Th1 proliferation, but inhibits Th2 and Th17 proliferation

23
Q

What two cell types are critically important for protection against viruses and tumours?

A

NK cells & CTLs

24
Q

We can visualise the immunological synapse by staining for __

25
Why is the immunological synapse important?
For preventing non-specific killing of cells - delivery of effector molecules is localised to the area of interest
26
Which CD4+ T cell subsets release barrier immunity activating effector molecules?
Th2 and Th17
27
What happens when the IL-2 gene is knocked out?
impaired Treg cell development and function
28
Mice with IFN𝛾 knockout are susceptible to...
intracellular pathogens like Mycobacteria and some viruses
29
What is another name for TGF-β?
Lymphotoxin-α
30
LT-α KO leads to...
absence of lymph nodes, disorganised spleen
31
IL-5 boosts growth and differentiation of __
eosinophils
32
IL-4 boosts growth of __
mast cells
33
Th17 cells stimulate recruitment of __
neutrophils
34
IL-10 inhibits inflammatory cytokine release from which innate immune cells in particular?
macrophages (particularly in the gut)
35
TNF-α knockouts are susceptible to...
Gram negative sepsis
36
IL-10 knockout leads to the development of __ in mice
IBD
37
What are DAMPs?
host-derived molecules (e.g. HMGB1) released by dying cells, which act as danger signals to the host immune system
38
Type 1 PAMPs direct...
maturation of DCs (IL-12 & IFN𝛾 release)
39
Type 2 PAMPs direct...
mature DC to present Ag (IL-4 predominant cytokine)
40
What dictates the cytokines produced by DCs?
The different combinations of PRRs expressed by different subtypes of DCs
41
Which form of IBD is characterised by the present of inflammatory macrophages?
Crohn's disease
42
Which form of IBD is characterised by the presence of neutrophils?
Ulcerative colitis
43
Which immune cells serve as sensors for the type 1 immune response?
DCs and macrophages
44
Which immune cells serve as sensors for the type 2 immune response?
epithelial cells (particularly in lung & gut) and mast cells