There are two different functional classes of dendritic cells

Question 1

From which progenitors to dendritic cells arise?

Answer 1

Both Myeloid and lymphoid progenitors

Question 2

After release from the bone marrow, where to, and via what route do DCs migrate?

Answer 2

via the bloodstream to tissues throughout the body and also directly to PLOs

Question 3

What are the two classes of dendritic cells?

Answer 3

cDCs (conventional dendritic cells)

pDCs (plasmacytoid dendritic cells)

Question 4

Which class of DCs participates most directly in antigen presentation and activation of naive T cells?

Answer 4

Conventional dendritic cells (cDCs)

Question 5

Which distinct lineage of DCs generates large amounts of interferons, particularly in response to viral infections, but do not seem to be as important for activating naive T cells?

Answer 5

Plasmacytoid dendritic cells (pDCS)

Question 6

What type of surface expressed protein to DCs have in common with macrophages and monocytes?

Answer 6

Integrins; they all have different integrin alpha chains and therefore display distinct beta two integrins on their surface.

Question 7

What is the predominant leukocyte integrin on conventional dendritic cells? By what other two names is this known?

Answer 7

alphaX:beta2. Also known as CD11c:CD18, or complement receptor 4 (CR4)

Question 8

What three things does CR4/CD11c:CD18 act as a receptor for

Answer 8

1. Complement C3 cleavage product iC3b
2. Fibrinogen
3. ICAM-1

Question 9

Other than DCs, what two other cell types express CD11c?

Answer 9

Monocytes and macrophages express low levels of CD11c

Question 10

What integrin to monocytes and macrophges also express at low levels, in addition to CD11c? By what two other names is this integrin known?

Answer 10

AlphaM:Beta2, AKA CD11b:CD18 or Mac-1

Question 11

Do pDCs express high levels of CD11c?

Answer 11

No

Question 12

By what marker may pDCs be identified in humans? What type of molecule is this? What may it’s function be?

Answer 12

Blood dendritic cell antigen 1 (BDCA-2, a C-type lectin, possibly involved in pathogen recognition

Question 13

DCs are found under most ………. …………, and in most …….. organs such as the ……… and ………. .

Answer 13

Surface epithelia
solid
heart
kidneys

Question 14

DCs under surface epithelia and in solid organs have an immune phenotype associated with (Low/high) levels of MHC proteins, and the …… costimulatory molecules. This makes them ready/not ready to stimulate naive T cells

Answer 14

Low levels of MHC proteins
B7 costimulatory molecules
Not ready to stimulate naive T cells

Question 15

What close relative of the DC also has the ability to recognise and ingest pathogens through receptors that recognise pathogen associated molecular patterns?

Answer 15

Macrophages

Question 16

Immature DCs are active in taking up antigens by phagocytosis by means of receptors such as …….. …. …. .

Answer 16

Lectin DEC 205

Question 17

Via what process to DCs non-specifically take up extracellular antigens?

Answer 17

Via macropinocytosis, in which large volumes of surrounding fluid are engulfed.

Question 18

Via what mechanism do DCs take up extracellular bacteria?

Answer 18

Receptor mediated phagocytosis

Question 19

On what molecule do DCs present antigens from extracellular bacteria, and what cell type do they activate?

Answer 19

MHC II, CD4 T cells

Question 20

Via what mechanism do DCs take up viruses?

Answer 20

The virus invades the DC

Question 21

Via what mechanism do DCs take up extracellular bacteria, soluble antigens, and virus particles?

Answer 21

Macropinocytosis

Question 22

On what molecule do DCs present antigens from viruses? What cell type do they activate?

Answer 22

MHC class I, CD8 T cells

Question 23

On what molecule do DCs present antigens from extracellular bacteria, soluble antigens, and virus particles? What cell type do they activate?

Answer 23

MHC II, CD4 T cells

Question 24

Via what route may viral particles taken up by phagocytic or macropinocytosis be presented? To what cell type?

Answer 24

Cross-presentation on MHC class I to CD8 T cells

Question 25

List five routes of antigen processing and presentation by dendritic cells

Answer 25

1. Receptor mediated phagocytosis
2. Macropinocytosis
3. Viral infection
4. Cross-presentation after phagocytic or macropinocytic uptake
5. Transfer from incoming dendritic cell to resident dendritic cell

Question 26

What type of particle can be transferred from incoming DCs to resident DCs for processing and presentation? On what type of MHC, for presentation to what cell type?

Answer 26

Viral particles, on MHC class I, to CD8 T cells.

Question 27

List 3 surface molecules associated with pDCs

Answer 27

MHC class II
BDCA-2
CXCR3

Question 28

List 10 surface molecules associated with cDCs

Answer 28

DC-sign
MHC class I
MHC class II
B7.1
B7.2
ICAM-2
ICAM-1
CCR7
LFA-1
CD58

Question 29

What class of cytokine is sectreted by pDCs? List two

Answer 29

Class I interferons, IFN alpha and IFN beta

Question 30

What types of intracellular receptors do pDCS express? For what purpose?

Answer 30

TLR-7 and TLR-9 for sensing viral infections