T Cell Immunity Flashcards
What is the function of the Th1 response?
The Th1 subset enhances and amplifies cellular mediated immunity by activating macrophages and/or promoting cytotoxic responses by CD8 cells.
What is the function of the Th2 response?
The Th2 subset promotes optimal antibody production.
What is the function of the Th17 response?
Th17 subset promotes chronic inflammation
What is the function of the Treg response?
T regulator subset modulates or suppresses
immune responses
What transcription factor is expressed in Th1 cells?
T-Bet
What is the trigger for a TMMI?
TLR on a DC
What cytokines are upregulated in a TMMI as an immature DC becomes a mature DC?
IL-12 and IL-18 are upregulated
What is the function of IL-12?
Obligatory Th1 helper initiator
What surface proteins are unregulated in antigen-activated Th1 cells?
CD28 and CD40L
What cytokines are generated by the Th1 cell in order to propagate the TMMI response?
IL-2 and IFN-
What are the initiation steps of the Th1 response?
- Pathogen binds the TLR on the DC
- DC produces IL-12 and IL-18 and presents to Th0
- Antigen is shown to the Th0 and along with the IL-12, this converts it to Th1
- Produces IFN-
What is the function of IFN-
It is a powerful macrophage activator and is the signature cytokine of the Th1 helper reaction.
What is IL-21 and what is it produced by?
IL-21 is produced by IL-12 activated Th1 cells.
It functions as a potent promoter of CD8 killing activity.
What is IL-2?
Critical growth cytokine produced by activated Th1 and CD8
What cells are dependent on IL-2?
Treg
What is the function of the Th1 reaction?
Th1 helper activation was developed to provide an antigen specific, efficient way to recruit highly activated macrophages to a site of infection. With a small amount of Th1 cells, a large number of macrophages can be recruited.
What is the tetrad of macrophage produced cytokines?
IL-1
IL-6
IL-8
TNF-α
What is the function of IL-1?
Promotes neutrophil growth and migration from the bone marrow and it is pro-inflammatory.
Acts with IL-6 to induce fever.
What is the function of IL-6?
Cause of fever and other inflammation signs.
Stronge effect on the growth and differentiation of B cells.
What is the function of IL-8?
Is the most potent stimulus for mobilizing and recruiting neutrophils to the site of infection
What is the function of TNF-α?
Key part of the inflammatory response and is a potent macrophage activator.
What is delayed hypersensitivity?
Old term for TMMI
What are the two paths of lymphocyte cytotoxic immunity?
- Natural Killer Cells
- CD8 Cytotoxic T Cells
Is there CD3 on NK cells?
No
Which path of lymphocyte cytotoxic immunity is non-antigen specific?
NK Cells
Are NK cells MHC restricted?
No
Why do NK cells not attack RBCs?
RBCs lack the surface proteins necessary for recognition
How is NK cytotoxicity turned off?
NK cell cytotoxicity is suppressed by killer cell inhibitory receptors (KIR) on their cell surface that recognize normal self MHC- Class 1 markers.
How does NK cytotoxicity occur?
Altered or absent MHC Class I cannot stimulate inhibitory signal and if activating receptor is present then cytotoxicity will occur and it will kill the cell.
What is another method that NK cytotoxicity can occur?
Recognition of cells bound with anitbody by
NK cells via the Fc receptors will lead to cello death
Which path of lymphocyte cytotoxic immunity is antigen specific?
CD8 Cells
What are the critical cytokines for CD8?
Critical initial cytokine signals are provided by activated NK cells that produce IL-21, IL-2 and IFN-
What are the two signals necessary for the CD8 to become cytotoxic?
- Antigen recognition
- IFN-
What turns off CD8 cytotoxicity?
Activated CD8,in the absence of specific targets, activate their own death genes by Fas/FasL.
-90% die off and 10% become memory cells
What transcription factor is found in Th2 cells?
GATA-3
What is the dominant cytokine inducing the Th2 reaction?
IL-4
When does a Th2 reaction occur?
– a Th1 TLR is not engaged and IL-12 not produced
– There are TLRs that induce DCs to produce IL-4 instead of IL-12
– when B cells present antigen
What is the function of IL-4?
Il-4 initiates and is an absolute requirement for a Th2 reaction. IL-4 is the growth hormone of a Th2 reaction-its major source is the Th2 cell
What is the function of IL-21 produced by the Th2 cell?
A potent B cell stimulator in the absence of IFN-
What cytokines are the major drivers of B cell differentiation?
IL-5, IL-6 and IL-10
What cytokines suppress Th1 reaction?
IL-4, IL-10 and IL-13
What is the main transcription factor in Th17 cells?
ROR
What is the main cytokine inducing Th17 cells?
IL-23
What cytokines are produced in the Th17 reaction?
IL-6
TGF-β
IL-23 (Main one)
What is the function of Il-17 that is produced in Th17 cells?
IL-17 is a potent recruiter of neutrophils
What suppresses Th17 reactions?
IL-4
IFN-
What is the main inducer of Treg reactions?
TGF-β
What is the main transcription factor of Treg reactions?
FoxP3