Cell Mediated Immunity Flashcards
What is the function of CTLs ?
Lysis viruses (obligate intracellular )
What is the function of T helper cell?
Activate Phagocytes by INf gamma to help it kill the microbe
Why does T helper cell activate phagocytes
Because phagocytes failed to lysis the microbe and this will cause multiplation of microbe which at the end kill the phagocyte itself
What will happen to the microbe in APC like dendritic cell after kill it ?
It’s Ag will be degraded into fragments ( peptides and epitopes) .
Epitopes are carried on ____ in phagocytes
Clefts (grooves) of MHC molecules
What TCL recognize only ?
Processed protein Ag (epitope) associated with MHC molecule
What is the Ag (epitope) binding site on MHC CLASS 1 AND MHC CLASS 2?
MHC CLASS 1 between alpha 1 and alpha 2.
MHC CLASS 2 between alpha 1 and beta 1
Name the cells that increase phagocytosis ability of phagocytes cells in innate immunity and adaptive immunity
Innate immunity is NK cells
Adaptive immunity is T helper cell
What is positive selection?
T Cell expressing TCR that recognize self MHC Molecule are selected to survive
If they doesn’t recognize they will be killed
What will happen to a t cell recognize self MHC molecules?
It will survive
In negative selection , what we call a t cell expressing TCR that recognize self peptide ? And what will happen to it?
Self reactive clones, and it is killed by apoptosis
If t cell expressing TCR recognize self peptide are not apoptosised it will cause
Autoimmune reaction
Which of the following t cells are released from thymus ?
Those recognize foreign (not self) Ag on associated with self (not foreign) MHC
A man who’s thymus in negative selection failed , what will happen to him?
Autoimmune reaction
What we call a t cell that mature before encountering Ag
Naiive
TCR ( t cell receptor) formed of alpha and beta polypeptide chain , each one contain 2 constant regions and 2 variable regions , name its functions
Constant region: attached to cell membrane
Variable regions: recognize
# specific peptide Ag (epitope)
# part of MHC molecules
Each t cell clone expresses TCR specific for 1 Ag (epitope)
True or False
True
What is epitope( antigenic determinant)
The smallest biochemical unit of Ag that bind specifically with Ag receptor on B and T lymphocytes
What does B and T lymphocytes only recognize?
Epitope
Name the cells that process exogenous Ag into epitopes
MQ , dendritic , B cell
What is the steps of CD4+ t helper cells activation in 2ry lymphoid organs
Step 1: TCR recognize its specific Ag (epitope) presented on MHC CLASS 2 Mol
Step 2: CD4 (coreceptor) interacts with MHC mol class 2 –> stabilizes interaction of TCR with its specific Ag.
Step 3: CD3 transmitts intracellular activation signal
What is the function of CD3 in t cells?
Signal transduction
Name APCs costimulator that interacts with T helper costimulator
B7 interacts with CD28
ICAM- interacts with LFA -1
CD40 interacts with CD40L (Ligand)
What we call t helper cell that doesn’t make 2nd signal?
Anergy or unresponsive cell
by the way this condition is rare
Viruses or intracellular bacteria are called
Intracellular organize/ microbe/pathogen
What we call the protein that degrade intracellular pathogen into peptides fragment
Proteasome
What is the source of expressed Ag for MHC class 1 and MHC class 2
MHC class1 : endogenously synthesis (new Ag) in cytoplasm (from intracellular microbes )
MHC class2 : exogenously phagocytesd Ag in phagolysosome
What is the function of IL2 and who produce it ?
Production:t helper cell
Function: clones expansion
What is clonal expansion?
Proliferation into cells with same Ag specificity and same TCR
Who activate T cytotoxic cells?
IL2 produced by t helper cells
What is the difference between CTL and T cytotoxic cells ?
CTL cotain 2 granules which T cytotoxic cells doesn’t acquire them
perforins and granzymes
What are the 2 markers expressed on infected cells to be recognized by CTLs ?
MHC class 1 and FAS(factor for apoptosis signal)
What are the steps of 1st signal of recognition of Ag and MHC on APC in t helper and t cytotoxic cells ?
1) TCR recognize its specific Ag (epitope) associated with MHC class2 (MHC 1 if the binding cell T cytotoxic)
2) CD4 (CD8 if the binding cell is T cytotoxic) work as coreceptor that interact with MHC class 1 or class 2 and stabilize interaction of TCR with its specific Ag
3) CD3 transmitted intracellular activation signal
CD 28 activate B7
False
Who will kill cells that doesn’t express MHC class 1 ?
NK cells
Only Adaptive immune cells have specific Ag receptor , which means that phagocytes and Nk killer’s does not have that
True
Who produce IL4 and what function does it do ?
Produced by Mast cell and t helper 2
Function: interact with naive t cells to become t helper 2 ( positive feed back )
Prevent with the help of IL4 , 10 , 13 MQ to produce IL12(cross regulation)
An immune cell induced by providing flammatory cytokines
Th 17
Name CD on NK and which of them are specific
CD 16
CD 56 (specific)
NK is activated by
IL 12 from MQ
Type 1 IFN ( innate immunity) and
IL 2 from Th 1 ( adaptive)
NK target
Virally infected cells
Cells with IC bacteria
Tumors
Name all NK receptor
Activating R
Inhibitory “
IL12 R
IL2 R
NK pathway Killing is
Perforin
T helper 1 is formatted in response to _______ & _______ by
_______ produced from _______&______
IC bacteria and viruses
IL12
MQ AND DC cells
Name the cells that secrete IFN gamma ( type 1 interferon)
T helper 1
NK
Function of IFN gamma are
activate of MQ (main stimulater) to kill bacteria
# Increases IgG (opsonin) from B cell
# Increases IL12 from APC —-> more T helper 1 (positive feedback) and decreases generation of T helper 2 (cross regulation)
# Increases TNF alpha and IL1 and IL 6(not mention in the book)
Note IFN gamma can be released from NK to + MQ
Name the cells that produce IL2 cytokines
T helper 1
Name the function of IL2
+ NK and Th , Tc ( t cell growth)
Name the cells that produce IL4
Mast cell
T helper 2
What is the main role of T helper 2
Immunity against helminthic infections
What will happen to MQ when IFN gamma activate it
Increase lysosomal protease and ROS and nitric oxide
Which cytokines activate eosinophil ? And who produce it
IL5 produced by T helper 2
عملية تصحيح
T helper 17 formated in response to _______&________
Fungi
Some Extracellular bacteria
T helper 17 is activated by
IL 6(proinflammatory] and TGF beta ( from dendritic cell)
Who produce IFN GAMMA and name all its function
Produced by NK and t helper 1
Function :
# + MQ
# production of IgG
Who produce IL2 and name its all functions
+ T cytotoxic & T helper cells
(T cell growth factor)
# + NK
