D2 Th cell polarization + ILC

Question 1

what type of Th development does the following produce

1. CD86/B7.2
2. CD80/B7.1
3. ICOS
4. OX40
5. 4-1BB
6. High MHC class II
7. Low MHC class II
8. APC
9. Cytokines and chemokines
10. Sites of antigen presentation
11. Host genetic background
12. BALB/c mice

Answer 1

1. induces Th2
2. neutral
3. Th2
4. Th2
5. Th1
6. Th1
7. Th2 (many allergens low binding affinity)
8. DC1/ DC2
9. Cell signaling
10. ILC
11. Th2
12. Th2

Question 2

what are the 4 major effects of cytokine production

Answer 2

((self serving))

1. Promote growth of subset that produces them
2. Inhibit development and activation of the opposite subset
3. Have opposing effects on target cells
4. Makes subset less responsive to opposite cytokine

Question 3

• what are lymphoid cells derived from
• what are the ILC
• what do they express
• How do they regulate Tc
• what do tissue signals activate

Answer 3

CLP: common lymphoid progenitor
- cytotoxic: NK | non cytotoxic: LTi (lymphoid tissue inducers), ILC1: T-bet, ILC2: GATA3, ILC3: RORyt
- express: IL-2Rα (CD25), IL-7Rα (CD127)
Regulate:
Directly: via Antigen presentation on MHC-II
Indirectly: via regulation DCs

Tissue signals expand and activate ILCs and effector functions of ILCs, mirror activation and functions of T cells.

Question 4

Describe ILC1

Answer 4

Innate counter part to Th1 
produces IFNy & TFNa
Polarises Th1 
Express T-bet
Immunity to intracellular bacteria
Weakly cytotoxic
Includes NK cells - (NK = efficiently cytotoxic)

Question 5

Describe ILC2

Answer 5

nuocyte: innate helper 2
Produce IL4, IL-5, IL-9, IL-13 and/or amphiregulin: (impt in activation of macrophages)
Require IL-7
Express – RORa and GATA3
Control of helminth infection
Allergic inflammation
Tissue repair

Question 6

Describe ILC3

Answer 6

2 subsets: Distinguished by expression of CCR-6 and RORyt
CCR-6+ -innate Th17
Immunity to extracellular bacteria
Chronic inflammation
Produce IL-17A, IL-22, GM-CSF

CCR-6- T-bet+
Produce TNF
Lymphoid tissue development: important
Intestinal homeostasis

Question 7

what cells do ILC translate into effector cytokines

Answer 7

Translate signal cytokines produced by myeloid & non-hematopoietic cells in tissues into effector cytokines that activate local innate and adaptive effector functions
DANGER signals

Question 8

what cells do ILC respond to

• ILC1
• ILC2

Answer 8

ILC1: IL-12, IL-15 & IL-18 (produced in response to intracellular pathogen)
ILC2: IL-25, IL-33, TSLP respond to epithelium derived cytokines, basophil-derived IL-4 in response to epithelial injury

Question 9

How do ILC regulate acquired immune responses?

Answer 9

• ILC activated quickly by tissue signals act upstream of acquired immune response
• (In contrast Tc must be selected and expanded on the basis of TCR specificity
• ILC express MHC class II thus present antigen to Tc
• Cytokines produced by ILC activate DC & macrophages
• ILC therefore promote Th development

Question 10

what is the link between the adaptive & innate response

Answer 10

ILC

• respond to danger by producing cytokines
• polarize Th4 response
• important in intestinal homeostasis