dendrites Flashcards
What triggers maturation of dendritic cells?
Innate danger signals from toll receptors or response due to tissue damage
Where are they found and what is their function
Periphery(skin and mucosa) , they are efficient at antigen capture but not at presentation
main role of dendrites
antigen presentation to cd 4 cells for t cell maturation
What mechanisms enable dendritic cells to capture antigens
Macropinocytosis
Receptor mediated endocytosis
phagocytosis
What is macropinocytosis
Formation of vesicles from the plasma membrane for non specific uptake
takes place in immature dendritic cells
What receptors are used to capture molecules
C type lectins
fc receptors
scavenger receptors
hsp receptors
What do they phagocytose , how is this activated
Bacteria, yeast , fungi , apoptotic bodies
receptor engagement by antigens
What role do langerhans cells and e cadherin play in migration
they interact with keratinocytes via e cadehrin which is reduced upon maturation
What is the function of ccr7
guides dendritic cells to lymph nodes through interactions with its ligands ,ccl21,ccl19
Why are dendritic cells essential for activating naive t cells
They are the only cells that can present antigenens to and activate cd4 and cd8 cells
How is antigen presentation regulated in dendritic cells
By their maturation cells , young cells are poor at it
What is the state MHC ll molecules in immature dendritic cells
Moderate expression on the surface
high endosomal ph
Low protease activity
high cysteine levels
How does maturation affect MHCll antigent presentation
Low endosomal /lysosomal pH
high protease activity
low cyteine levels
high expression of mhc 2
What is cross presentation in dendritic cells
The ability to present exogenous antigens on MHC class 1 molecules to activate naive cd8 cells
Why is cross presentation improtant
it allows activation of cd8 cells wheter the dendrite is infected themselves
