Immune-2 Flashcards
what are cells that express CD4
helper T cells
what happens when naive helper T cells interact with DCs
they differentiate into TH1, TH2, TH17, THreg
what does the type of TH cell depend on
the specific type of cytokine released from the DCs
what determines the the specific type of cytokine released from the DCs
the specific type of pathogen
what 2 things characterize each TH cell
the cytokines that they produce, the innate immune effector mechanism that is activated
what are the three phases in CD4 T cell activation
recognition, activation, effector
what happens in recognition phase
macrophages display foreign antigens on their surface in a form that can be recognized by antigen-specific TH lymphocytes.
what happens in activation phase
TH cells produce cytokines that promote the proliferation and differentiation of the T cells as well as other cells, including macrophages
what happens in effector phase
activated macrophages carry out phagocytosis and cytolysis
what is a super important thing that is released during T cell activation (CD4+)
the release of IL-2
what is the role of IL-2 + how do they work
These are essential to allow maturation of t cells
It works in autocrine mechanism, they start proliferating, dividing - clonal expansion
what is the 3 signals in CD8+ T Cell activation
TCR-MHC class interaction
co-stimulation
pro-inflammatory cytokines
what is the early outcome of CD8+ T Cell activation
no cytokine secretion
what is the late outcome of CD8+ T Cell activation
clonal expansion and cytotoxicity
what are the 3 mechanisms of CD8 killing
- granzymes
- Fas ligand on their surface (death receptor)
- make cytokines, like TNF-alpha
what happens to T cells with T cell activation + how
increased T-cell survival and differentiation through production of cytokines like IL-2
what happens to metabolism with T cell activation
increased
what happens to cell survival genes with T cell activation
upregulated
what happens to cell division with T cell activation
upregulated
what happens to cytotoxic cells with T cell activation
they are activated (killer functions)
what happens to memory cells with T cell activation
they become activated
why do you have death of t cells as a consequence with t cell activation
because you need to down regulate the immune response
what are the 2 transcription factors that are activated once the t cell receptor is activated
NFAT and mTOR
what is the role of NFAT
the activation of T cells, increases IL 2 production and also more proliferation and differentiation
what is the role of mTOR
activation, differentiation and migration
what activates mTOR
IL2 and TCR
is t cell activation regulated
yes highly
what are the 2 checkpoints for the immune pathway
CTLA-4 and PD1
what is the point of checkpoints for t cell activation
to balance protective immunity and immunopathology
what is a bad thing about the immune checkpoints
during responses to chronic pathogens, they can limit protective immunity
which is the leader of the immune checkpoint inhibitors
CTLA-4
what causes CTLA-4 to be upregulated
stimulatory signals from both TCR and CD28(B7) binding induces upregulation of CLTA-4 on cell surface