What Q: does antigen presentation refer to?
A: Peptides presented within MHC class I/II clefts to the T-cell receptor (TCR).
Q: For T cell recognition of a foreign element, T cell will only recognize:
A: Peptides, linear sequences and the peptide in context.
Q: What is MHC restriction?
A:Specific T cells recognize foreign peptide sequences within the cleft of a self MHC molecule.
Q: Can MY T cells recognize a peptide in the cleft of YOUR class I/II proteins?
A: No, unless we have identical class I/II proteins.
Q: How has the immune system solved the problem of killing both extracellular and intracellular pathogens?
A: It kills infected cells with cytotoxic T cells, and produces antibodies to neutralize extracellular pathogens.
Q: What kind of cells have MHC class II molecules?
A: Antigen presneting cells (Accessory cells): B cells, Macrophages, Dendritic cells.
Q: How do B cells take up protein? Is this method efficient?
A: Proteins is taken up through Ig complexes and complement receptors on the surface of the cell. This is very efficient, as Ig bind antigen with high affinity.
Q: What are Langerhans cell, and where are they located?
A: They are dendritic cells, and are located in the skin.
Q: What do dendritic cells do upon the uptake of antigen?
A: Process it and migrate from the into periphery lymph nodes for activation of T cells.
Q: What organelle is responsible for digestion of antigen into peptides for the exogenous pathway?
A: lysosome
Q: Which MHC molecule has an invariant chain prior to being loaded with a peptide?
A: MHC II
Q: Where is the MHC II loaded with peptides and, are these peptides derived from endogenous or exogenous proteins?
A: The MHC II is loaded in the vescle formed by the fusion of the lysosome with the MHC vesicle. The peptides are of exogenous origin.
Q: Where is the MHC I loaded with peptides, and what organelle generates these peptides?
A: The MHC I is loaded in the RER with peptides that have been generated from the proteasome.
Q: How long do peptide expressing MHC I/II exist on the cell surface?
A: MHC II lasts a...