T cell mediated immunity 1 Flashcards
What is the first thing that happens during an active immune response?
T cell activation
What is MHC restriction?
A person’s own t cell population has developed to recognise their own MHC molecules
What happens when CD8 t cells become activated?
They become a cytotoxic t cell/killer t cell
What cells do cytotoxic t cell kill?
Self cells, not pathogens
Why do cytotoxic t cells kill self cells?
The self cells they kill are infected w/ a pathogen
Generally, what do activated CD4 t cells become?
Helper T cells
Which immune response first activates in response to a pathogen you’ve never seen before?
Innate immune response
Why does the innate immune system activate first when you encounter a pathogen you have not seen before?
Pattern recognition–> things like lipopolysaccharide are on pathogens but not on our own cells
What is injected alongside a protein in a vaccination?
An adjuvent
Examples of an adjuvant injected alongside proteins in a vaccine?
lipopolysaccharide
Why are adjuvants injected alongside proteins in vaccines?
To activate the innate immune system
What components of a virus can be recognised as foreign?
Things to do with the nucleic acids
What cells are activated as part of the innate immune response?
Dendritic cells
What do dendritic cells do as part of the innate immune response?
Take up a pathogen
Which MHC molecules would be used if a dendritic cell takes up a bacteria?
MHCII
Which MHC molecules would be used if a dendritic cell takes up a virus?
MHCI
What do dendritic cells do when activate as part of the innate immune respose?
Migrate to 2ndary lymphoid tissues
What guides dendritic cell migration to 2ndary lymphoid tissues?
Chemokines–> express chemokine receptors
What do dendritic cells express when activated (to do with t cells)?
Co-stimulatory molecules
How does the dendritic cell activate a T cell?
MHC molecule presents the peptide/antigen to the naive t cell population
What interaction between a t cell and antigen presenting dendritic cell is needed to activate the t cell?
The TCR needs to recognise the MHC-antigen complex, and the costimulatory signals need to signal to the t cell as well
What do tolerance mechanisms do?
Only allow t cells that don’t recognise self peptides to develop
What happens after a dendritic cell activates a t cell?
The t cell starts to replicate, and becomes an infector or memory t cell
What is different about t cell activation the second time you encounter a pathogen (and thus antigen) compared to the first?
The stringent activation criteria (costimulation criteria) are not needed
What to Th1 cells do?
Activate macrophages infected with the pathogen, and help them kill the pathogen
What does TfH cell stand for?
Follicular helper t cells
What do both Th2 and TfH cells do?
Help antibody responses
What do Treg cells do?
Dampen down the immune responses
