Antigen Presenting Cells Flashcards
Which are the ONLY cells wich are able to activate naive T cells?
Those who have never been in contact with an antigen before.
Dentritic cells
The mos important APC
What determines if a T cell will have a cytotoxic or helper response?
The type of MHC they encounter.
(CD8) MHCI - cytotoxic
(CD4) MHCII - helper
Where are inactivate Dentritic Cells?
In peripheral areas
Skin, Mucosa…
Connective tissue, epithelia
Where are DC in the spleen?
Cortical regions
Where are macrophages in the spleen?
Marginal sinus and medullary cords
Where are B cells in the spleen?
Follicles
Why do mature dentritic cells stop their capacity to uptake antigens?
As in it’s way to the lymph node it may encounter self antigens. By this way the chances of producing an autoimmune reaction are reduced.
What type of molecules stimulate the movement of cells?
Give an example
Chemokines
CCR7
Binds to CCL19 and CCL21
Which are the only cells able to do cross presentation (cross priming)?
cDC 1
Conventional Dentritic Cells
So they are the only ones able to activate cytotoxic responses (CD8)
What’s cross priming?
The abiliity to present Ag in MHCI and therebefore present them to cytotoxic T cells.
Which dentritic cells come from a lymphoid progenitor?
pDC
Plasmacytoid dendritic cells.
What do pDC produce?
Many proteins as interferon type 1
Activator of cytokines after the contact with viruses.
Which cells participate in antiviral innate immunity?
pDC
Plasmacytoid Dentritic Cell
Which cells express TNFalpha and ROS?
Monocyte-derived DC
Which cells are the first immunological barrier to the external enviorenment?
Langerhans cells
Pathway of antigen presentation of MHC I and II.
MHC I - endogenous processing
MHC II - exogenous processing
What pathway is presented in all cells?
Endogenous pathway
All cells can be infected by viruses and they alarm the immune system.
How is the threat of presenting self-antigens mitigated during protein processing?
This is to avoid autoimmunity.
Through the change of the proteosome to an immunoproteosome.
Only found in infected cells and triggered by interferon gamma.
In what organelle is MHC generated?
In the RER.
How is the transmembrane protein wich allows the transport of antigens insde the RER called?
TAP
Transporter of antigen processed molecules
ERAP1
Endoplasmic Reticulum Amino Peptidase
Which cells detect the abscence of MHC?
This happens mostly in cells infected by virus.
Natural Killer Cells
What is the function of the Invariant chain?
Transport of MHCII to endocytic vesicles (where the peptides are) and prevents peptides from binding to MHCII too early.
Function of HLA-DO and HLA-DM.
HLA-DO (oscuro) eliminates the CLIP.
HLA-DM (mañana) exchanges the CLIP for a peptide fragment.
Which cells express MHC I?
And MHC II?
MHCI - All nucleated cells.
MHC II - only APCs.
