Monocyte, Macrophage, And Dendritic Cell Production

Question 1

Interferon-y-responsive transcription factor (IRF8) promotes ____ differentiation and inhibits ____ production.

Answer 1

Promotes monocyte differentiation
Inhibits granulocyte production
(IRF8 persists in monocytes and macs, declines in neuts)

Question 2

Bacterial infections increase monopoiesis through what signaling pathway?

Answer 2

Toll-like receptor (TLR) signalling, which increases C-C motif chemokine ligand 2 (CCL2) in the bone marrow and causes rapid monocyte emigration

Question 3

Give a very general characterization of Ly6C high and Ly6c low monocytes

Answer 3

Ly6C high - proinflammatory monocytes that express high CCR2 (help monocytes emigration) and low CxCR1 (allows endothelial cell adhesion)
Ly6C low - patrolling monocytes in the blood stream/healing tissues

Question 4

What are the three main sources of tissue macrophages?

Answer 4

Embryonal yolk-sac (microglia production)
Fetal liver monocytes/premacrophages (erythro-myeloid progenitors - EMPs)
Ly6C+ monocytes that arrive in tissues during inflammation - (esp. intestinal and skin/dermal macs)

These macrophages are characterized by the ability to self-renew and self-maintain in adult tissues

Question 5

What is the most important transcription factor in macrophage development?

Answer 5

PU.1

Question 6

Briefly describe the two main subgroups of dendritic cells and key growth factors

Answer 6

Common and plasmacytoid dendritic cells -> arise from committed DC progenitors (CDP) with FLT3 as a key growth factor for their development
Monocyte-derived dendritic cells (MoDC) -> arise from monocytes and are key in inflammatory DC and steady-state DC in the mucosa and dermis -> M-CSF is a key growth factor