Dendritic cells Flashcards
How many subsets of DCs?
5 subsets: two cDCs, plasmacytoid DCs, monocyte derived DCs and Langerhans cells.
How many subsets of classical DCs, and where are they found?
2, found in both SLO and in non-lymphoid organs.
characteristics of immature DCs?
highly phagocytic
Characteristics of mature DCs?
low phagocytic activity and high expresssion of co-stimulatory molecules nad migraty receptors.
where are immature DCs present?
in SLOs (resident DCs) and in all non-lymphoid organs apart form CNS parenchyma.
Put develoment in right order: CD8+ cDC, CD11b+ cDCs, CDP, pDC, monocyte, CMP, GMP
CMP, GMP, CDP, pDC and CD8+/ CD11b+ cDCs.
what are the Tfs for pDC, CD8+ cDCs, and CD11b+ cDCs
pDCs, E2-2, CD8+ cDCs: Batf3, CD11b+ cDCs: IRF4.
what ligand can induce expansion of all populations of DCs?
Flt3L
How does the cDC CD8+ differ to T cells?
CD8 on DCs is a CD8+aa homodimer rather than an B heterodimer.
Are DC1 and DCII populations in SLO and NLO similar?
Yes they are almost identical transcriptionally, although different markers (probably due to homing etc.)
what is CD11b?
Along with CD18 (B2) it forms the complement receptor 3 (CR3)
what is Cd18 and what PID is it associated with?
CD18 is the (B2) subunit of an integrin adhesion molecules. Defects in this gene are associated with LAD-1.
Can also pair with CD11b in a heterodimer to form the CR3 complement receptor 3.
How do DCI and DCII differ in TLR expression? What might this mean?
TLR3 is higher in DCI- recognises dsRNA), TLR7 and TLR5 in DCII are higher and recognise ssRNA and flagella respectively.
What do cDCI potentially preferentially sense?
Can sense at different points of infection, and towards intracellular and dead and dying cells.
What four markers can you use for plasmacytoid DCs?
CD4+ CD3-, CD11c low, B220
what is a human pDC specific marker?
BDCA2
whats weird about pDC pehontype?
its expresses CD4+, and also shows evidence of Ig D-J recombination
what cytokine do pDCs highly express in infection?
type 1 IFN
what are 3 effects of pDC type I IFN production?
- IFN-1 stimulates the maturation of cDCs. 2. modulates MHC II pathway, enhancing endosomal sampling 3. shuts down the efferent lymph to increase retention of lymphocytes and DCs in LNs (may enhacene T cell memory formation)
what does mTEC stand for? and what kind of selection do they take part in?
medullary thymic epithelial cell, take part in negative selection within the thymus.
What is the TF regulator involved in expressed of tissue restricted antigens? (TRAs?)
AIRE
Process by which mTECs can also express AIRE derived antigens on MHC II?
macroautophagy
3 possible ways that DCs may help contribute to negative selection in thymus?
- provide DC self-antigens (which may also be like common haematopoietic antigens). 2. Can express AIRE to present TRAs. 3) If migratory, may be able to present other tissue antigens from the periphery.
When might migratory pDC and (potentially cDCs) be excluded from the thymus?
During upregulation of co-stimulatory molecules and after activation of TLRs in infection and inflammation.
What markers help differentiate the two moDCs? And which is the major and minor population?
CD14+ the major pop. Cd16+ the minor population.
Aside from infection and inflammation, injection of ‘what’ in skin and blood helps induce moDC development and migration to SLOs?
Injection of particles.
Where do Langerhan cells do antigen sampling?
The skin processes through stratum corneum (vs cDCs in the dermis).
Where cells are pDCs, LCs, and cDCs derived from?
pDCs from the CDP (cmmon dendritic precursor), LCs from Yolk sac and can be replenished from BM, cDCs form precursor DCs.
What unique physiological structures do LCs have?
birbeck granules (also express langerin)
What monocyte marker do sampling DCs in the intestine have?
The cheomkine recepotr CX3CR1.
