Cellular Immune Response Flashcards
The cellular immune response, infected cells can be cleared by what two general actions.
Cells are killed
Activated to kill and destroy intracellular organism
MHC I presents antigens to _________
CD8 cytotoxic Tcells
What are the two main mechanisms of Tcell cytotoxicity ?
Intrinsic - Granzyme released from Tcell
Extrinsic- CD95L on cell surface binds to CD98
Both lead to cascade activation and apoptosis
What are the three types of caspases?
Initiator caspase - activated by death complex
Effector caspase -break down cellular structures
Inflammatory caspase -activated by inflammasomes
When an TCR binds to MHC I, ___________ is released from the dendritic to activate the Tcell
IL12
During cell cooperation between a CD8+ cell bound to MHC and CD4+ bound to the same dendritic cell, the CD4+ cell will release what cytokines to enhance the cellular immune response
CD4+ Th1 releases
IL22 and CCL22 to positive feedback to dendritic cell
IL2 and IFNy to activate CD8+ cell
In an immunological synapse between a cytotoxic Tcell and its target, the outer ring consists of ___________, an inner ring with ________, and a central zone with ____________ and _____________
Adhesion proteins (iCAM) Costimulatory proteins (CD2/CD40) Apoptotic mechanisms (FasL/Fas and Perforins) and TCR/MHC with costimulatory molecules
What molecule is important in intracellular adhesion between a cytotoxic Tcell and target cell and what are the functions?
iCAM
TCR and MHC with costimulatory molecules move between these adhesion molecules and localize the cytotoxic activity
What is a non-MHC restricted mode of cell death?
Nitric oxide (NO) released by macrophages
ADCC
Pe for instance (NK cells)
Macrophage activation requires what two cytokines released by and APC to activate the Th1 cells which will release what two cytokines leading to the activation of the macrophage .
APC -> IL12 and IFNy -> Th1 activated -> IL2 and IFNy -> activated machrophage —–> bacterial destruction
What are the two classical pathways of machrophage activation?
Innate: NKcells release IFNy (not fully activated, requires IL2)
Adaptive: Th1 release IFNy and IL2
Macrophages can differentiate into M1 or M2 macrophages. M1 cells differentiation is caused by cytokines from ____________ cells. M2 cell differentiation is caused by cytokines from ______________ cells.
M1- Th1 cells
M2- Th2 and Tregulatory cells
M1 promote _____________, and M2 cells promote __________________
Inflammation
Resolution of inflammation
Resolution of inflammation, regulated by M2 macrophages promotes ?
Wound healing
ECM
Cell proliferation
Angiogenesis
What are the characteristics of effector memory Tcells
CD44+ Increased IL2 receptors Increased adhesion molecules Increased IL4 and IFNy Increased TCR stimulation IL15->Tc memory survival Human Tcell memory survival 8-15yrs
What are the steps following TCR and CD3 activation leading to cell division and cytokine synthesis ?
CD3 transmit signal
Protein kinases activated
Transcription factors activated
Gene transcription
A strong signal into the Tcell requires both antigen and ___________
Costimulation by CD28
Antigen by itself promotes a weak signal unless there is a high amount of that antigen
What is a superantigen?
Bind to variable region of TCR and MHCII producing a strong signal
What are the sub populations of helper Tcells and what immune response do they take part in?
Th1 - cellular
Th2 -humoral
Th17- inflammation
What is required for differentiation of helper Tcells?
Costimulation and cytokine production
What co- stimulators molecules are required to activate Th1?
CD80 and IL-12
What costimulatory molecules are required for Th2 cell activation ?
CD86 and IL-1
Th1 produces what types of cytokines?
IL-2
IFNy
TNFB
TNFa
GM-CSF
IL-3
IL-2 and INFy produced by Th1 have an _____________ effect on Th2
Inhibitory
What cytokines are produced by Th2??
IL-4
IL-5
IL-10
IL-13
TNFa
GM-CSF
IL-3
IL-4 and IL10 have an _____________ effect on Th1
Inhibitory
IL-4 is an antagonist to what two cytokines produced by Th1 cells
IL-2 and INFy
Activation of Th1 produces what 3 main effects
Tcell cytotoxicity
Macrophage activation
Some IgG production
Activation of Th2 cells causes production of?
Bcell activation -> IgG, IgA, and IgE
What are the main three functions of IFNy?
Activates NK cells
Activates macrophages
Antiviral
What are the main functions of IL-2?
Promote Th1 activation
Promotes Bcell proliferation
Active macrophage and NKcells
Controls Tregulatory cells
What are the main functions of IL-4
Stimulate Bcells
Activate macrophage
Suppresses TH17 and Th1
Antagonize IFNy and IL2
What is the main function of T17
Produce pro-inflammatory cytokines
Bcell helper
__________ Tcells can act as innate immune cells with invariant antigen receptor OR as adaptive Th cell with TCR of polyclonal origin
Y/delta
