lecture 34 Flashcards
(13 cards)
1
Q
what are the main cells involved with immunity?
A
white blood cells
2
Q
how does antigen sampling + presentation work?
A
- dendritic cells present in major organs
- phagocytose antigen
- process into peptides
- DC migrate from organs to drain to lymph nodes
- present peptides on MHC to T cells
3
Q
how does cytotoxic T cell activation work?
A
- Antigen presenting cell phagocytoses antigen
- MHC-II peptide complex binds with TCR of CD4 T helper cells
- releases cytokines to CD8 cytotoxic T cell
- MHC-I peptide complex binds with TCR of CD8, activated by cytokines
- TCR of CD8 binds to MHC-I of peptide complex of virally infected cell
- kills cell with apoptosis using perforin and granzyme
4
Q
CD4 T cells make…
A
antibodies and cytokines
5
Q
CD8 T cells are…
A
cytotoxic
6
Q
what is an antigen?
A
- has the potential to be recognised
by the immune system
7
Q
what is the purpose of antigen uptake?
A
- Clearance of pathogens (innate response)
- For presentation to T cells (adaptive response)
8
Q
what immunity do invertebrates have?
A
innate only
9
Q
what immunity do vertebrates have?
A
innate and adaptive
10
Q
what is MHC-I?
A
- endogenous/intracellular
- expressed on all nucleated cells
11
Q
what is MHC-II?
A
- exogenous/extracellular
- only on antigen presenting cells
12
Q
how does the MHC-I antigen presentation pathway work?
A
- virus infects, produces viral proteins
- host cell translates viral RNA into viral proteins using ribosomes
- viral proteins are degraded by the proteasome, a protein complex that chops them into peptides
- peptides are transported to the ER, where they are loaded onto MHC-I molecules.
- The peptide-MHC-I complex is then transported to the cell surface
- CD8 T cells recognise and kill cells which present peptide
13
Q
how does the MHC-II antigen presentation pathway work?
A
- Phagocytosis of Exogenous Antigen
- forms phagolysosome, breaks antigen into peptides
- loaded onto MHC-II
- MHC-II transported to cell surface, visible to helper T cells
