Exam 3 Lecture 14: Unconventional Immune Cells

Question 1

Features of Innate-like lymphocytes

Answer 1

1. Derived from the lymphoid lineage
2. Bridge the innate and adaptive arms
   of the immune system
3. Lower diversity in receptors that
   conventional T cells
4. Quicker to respond
5. Their receptors do not recognize the
   classic “peptide-MHC” complexes of
   conventional T cells

Question 2

Which cells are innate like lympocytes

Answer 2

NK cells ILCs Gamma-
delta T cells
Group 1
CD8 T cells
NKT cells MAIT cells

Question 3

How do NK cells balance activating and inhibitory signals

Answer 3

Activation
Use many different receptors to monitor the health of other cells using MHC I expression as a surrogate
Requires 2 activating signals from a target cell

Inhibition
CD94:NKG2A interaction with HLA-E prevents NK cell from attacking healthy cells
Killer-cell immunoglobulin-like receptors (KIRs) bind to HLA (MHC class I) molecules directly & directly monitor specific HLA types

Question 4

How do NK cells monitor for sick and damaged cells that have downregulated MHC I

Answer 4

Abnormal cells lacking MHC-class I cannot inhibit NK cells and so are killed

Question 5

What are the different types of Innate Lymphoid Cells? What role do they serve (as a whole)

Answer 5

Secrete cytokines that regulate both innate and adaptive cells
NK
ILC 1
ILC 2
ILC 3
LTi

Question 6

Features of NK cells

Answer 6

Cell type: CD8+
Stimuli: intracellular virus, bacteria, protozoa, cancer
Mediator: perforin, granzymes, IFN-g
Response: type 1 immunity, cell meditated cytotoxicity

Question 7

Features of ILC1

Answer 7

Cell type: Th1 CD4+
Stimuli: intracellular virus, bacteria, protozoa, cancer
Mediator: IFN-g
Response: type 1 immunity, conventional inflammatory activation of macrophages

Question 8

Features of ILC2

Answer 8

Cell type: Th2 CD4+
Stimuli: extracellular infection w/ large multicellular parasites or allergens
Mediator: IL-4, IL-5, IL-13
Response: Type 2 immunity w/ noninflammatory activation of macrophages

Question 9

Features of IL3s

Answer 9

Cell type: Th17 CD4+
Stimuli: extracellular bacteria or fungi
Mediator: IL-22, IL-17
Response: Type 3 immunity, promote phagocytosis and secretion of antimicrobial peptides

Question 10

Features of Lymphoid-tissue inducer (LTi) cells

Answer 10

Cell type: Tfh CD4+
Stimuli: mesenchymal organized cells, retinoic acid, CXCL13, RANK ligand
Mediator: lymphotoxin, TNF
Response: formation of secondary lymphoid tissues

Question 11

What are the features of gamma-delta T cells that differ from alpha-beta T cells? What antigens do they recognize

Question 12

What are the three types of unconventional alpha-beta T cells

Question 13

What is trained immunity

Answer 13

long-term changes to the
innate immune response