Antigen Processing Flashcards
1
Q
Describe the process of Intracellular pathogen presentation.
A
- Proteins are in the cytosol and tagged with ubiquitin via ubiquitin ligase and degraded by proteasome to produce peptides in cytoplasm.
- Peptides are transported into ER lumen by TAP.
- Peptides loaded onto MHC class 1 in ER lumen.
- MHC 1-peptide complex transported to CM for presentation.
2
Q
Explain Cross-Presentation.
A
- Dendritic cells (only) phagocytoses infected cell or tumor cell.
- Phagocytosed cell is digested in phagolysosome.
- Some of the peptides are loaded into MHC 2.
- The rest is taken out of phagolysosome and into cytoplasm.
- The protein is degraded by a proteosome
- Peptides are transported into ER lumen and loaded into MHC 1.
3
Q
What do MHC molecules bind to?
A
They bind to the CD4 or CD8. NOT to the antigen or the TCR.
4
Q
When a tumor cell is attacked by a CD8, how does that cell die?
A
It dies by apoptosis, NOT osmotic lysis.
5
Q
What is the advantage of cross-presentation?
A
It can activate both CD4 and CD8.
6
Q
What building block does MHC 1 and 2 bind?
A
ONLY PEPTIDES
7
Q
How doe herpes simplex avoid the immune system?
A
Inhibits antigen presentation; An HSV protein interferes with the TAP transporter.
8
Q
How does Cytomegalovirus avoid the immune system?
A
Inhibits proteasomal acitivity; Removal of MHC 1 molecules from ER.
9
Q
How does the Epstein-Barr virus avoid the immune system?
A
Inhibition of proteasomal activity.
