Lecture 43: Flashcards
1
Q
What is an antigen?
A
anything recognised by the immune system that is foreign
* autoimmune disorders attack it self
2
Q
What are the roles of antigen presenting cells?
A
APC display peptides of microbes on cell surface to other cells of the immune system
peptides of pathogens are displayed on MHC complex, these complexes are surveyed by antigen specific T cells
3
Q
What are endogenous antigens displayed on?
A
- intracellular = virus, cancer & tumours
- —> MHC-I
- —-> displayed on all nucleated cells
- APC loads peptides on MHC-I & MHC-II to kick start the immune system
4
Q
What are exogenous antigens displayed on?
A
- extracellular = bacteria = outside
- —-> MHC-II
5
Q
How are endogenous antigens processed?
A
- pathogen is degraded within the cytoplasm
- peptides are imported to the ER where MHC-I is synthesised
- peptides are loaded onto MHC-I in ER and exported to cell surfaced —> expressed on all nucleated cells
6
Q
How are exogenous antigens processed?
A
- pathogen is degraded within a phagolysosome
- peptides are loaded onto MHC-II in phagolysosome then exported to cell surface
