3. Antigen presentation to T cells by MHC Flashcards
Which MHC presents viral epitopes?
MHC I
Which MHC presents cytosolic pathogens
MHC I
Which MHC presents intravesicular pathogens?
MHC II
Which MHC presents extracellular pathogens and toxins?
MHC II
Complex which transports peptides from the cytosol to the ER
TAP complex
How do cytokines change the proteasome to the immunoproteasome
Changes the beta subunit which alters the C terminal of the peptide which is broken down - makes C terminal into a hydrophobic AA which can bind to the MHC
What does the chaperone protein calnexin do?
Holds the alpha chains in place until beta 2 micro globulin binds
Which 2 chaperone proteins are involved once beta2 micro globulin binds?
Calreticulin holds the MHC in place in a complex with ERp57
How is the assembled MHC in the ER linked with the Tap complex?
Chaperone protein tapasin binds to the TAP complex
Which protein tries the peptides which enter the ER to 8-10AA length?
ERAAP
Example of virus that interfere with MHC I presentation and how
Adenovirus - protein 19 competes with tapasin and inhibits peptide loading into MHC I
Why doesn’t MHC II bind peptides going into the ER?
Invariant chain - sits as a trimer bound to 3 class II molecules at a time and blocks the binding grooves
What is the name of the fragment left behind once invariant chain is cleaved?
CLIP
What binds to MHC II and causes the CLIP to be released?
HLA-DM
Most polymorphic gene region for MHC II
DRB
