Cell Mediated Immunity

Question 1

What is the function of CTLs ?

Answer 1

Lysis viruses (obligate intracellular )

Question 2

What is the function of T helper cell?

Answer 2

Activate Phagocytes by INf gamma to help it kill the microbe

Question 3

Why does T helper cell activate phagocytes

Answer 3

Because phagocytes failed to lysis the microbe and this will cause multiplation of microbe which at the end kill the phagocyte itself

Question 4

What will happen to the microbe in APC like dendritic cell after kill it ?

Answer 4

It’s Ag will be degraded into fragments ( peptides and epitopes) .

Question 5

Epitopes are carried on ____ in phagocytes

Answer 5

Clefts (grooves) of MHC molecules

Question 6

What TCL recognize only ?

Answer 6

Processed protein Ag (epitope) associated with MHC molecule

Question 7

What is the Ag (epitope) binding site on MHC CLASS 1 AND MHC CLASS 2?

Answer 7

MHC CLASS 1 between alpha 1 and alpha 2.
MHC CLASS 2 between alpha 1 and beta 1

Question 8

Name the cells that increase phagocytosis ability of phagocytes cells in innate immunity and adaptive immunity

Answer 8

Innate immunity is NK cells
Adaptive immunity is T helper cell

Question 9

What is positive selection?

Answer 9

T Cell expressing TCR that recognize self MHC Molecule are selected to survive
If they doesn’t recognize they will be killed

Question 10

What will happen to a t cell recognize self MHC molecules?

Answer 10

It will survive

Question 11

In negative selection , what we call a t cell expressing TCR that recognize self peptide ? And what will happen to it?

Answer 11

Self reactive clones, and it is killed by apoptosis

Question 12

If t cell expressing TCR recognize self peptide are not apoptosised it will cause

Answer 12

Autoimmune reaction

Question 13

Which of the following t cells are released from thymus ?

Answer 13

Those recognize foreign (not self) Ag on associated with self (not foreign) MHC

Question 14

A man who’s thymus in negative selection failed , what will happen to him?

Answer 14

Autoimmune reaction

Question 15

What we call a t cell that mature before encountering Ag

Answer 15

Naiive

Question 16

TCR ( t cell receptor) formed of alpha and beta polypeptide chain , each one contain 2 constant regions and 2 variable regions , name its functions

Answer 16

Constant region: attached to cell membrane
Variable regions: recognize
# specific peptide Ag (epitope)
# part of MHC molecules

Question 17

Each t cell clone expresses TCR specific for 1 Ag (epitope)
True or False

Answer 17

True

Question 18

What is epitope( antigenic determinant)

Answer 18

The smallest biochemical unit of Ag that bind specifically with Ag receptor on B and T lymphocytes

Question 19

What does B and T lymphocytes only recognize?

Answer 19

Epitope

Question 20

Name the cells that process exogenous Ag into epitopes

Answer 20

MQ , dendritic , B cell

Question 21

What is the steps of CD4+ t helper cells activation in 2ry lymphoid organs

Answer 21

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

Question 22

What is the function of CD3 in t cells?

Answer 22

Signal transduction

Question 23

Name APCs costimulator that interacts with T helper costimulator

Answer 23

B7 interacts with CD28
ICAM- interacts with LFA -1
CD40 interacts with CD40L (Ligand)

Question 24

What we call t helper cell that doesn’t make 2nd signal?

Answer 24

Anergy or unresponsive cell
by the way this condition is rare

Question 25

Viruses or intracellular bacteria are called

Answer 25

Intracellular organize/ microbe/pathogen

Question 26

What we call the protein that degrade intracellular pathogen into peptides fragment

Answer 26

Proteasome

Question 27

What is the source of expressed Ag for MHC class 1 and MHC class 2

Answer 27

MHC class1 : endogenously synthesis (new Ag) in cytoplasm (from intracellular microbes ) MHC class2 : exogenously phagocytesd Ag in phagolysosome

Question 28

What is the function of IL2 and who produce it ?

Answer 28

Production:t helper cell Function: clones expansion

Question 29

What is clonal expansion?

Answer 29

Proliferation into cells with same Ag specificity and same TCR

Question 30

Who activate T cytotoxic cells?

Answer 30

IL2 produced by t helper cells

Question 31

What is the difference between CTL and T cytotoxic cells ?

Answer 31

CTL cotain 2 granules which T cytotoxic cells doesn't acquire them perforins and granzymes

Question 32

What are the 2 markers expressed on infected cells to be recognized by CTLs ?

Answer 32

MHC class 1 and FAS(factor for apoptosis signal)

Question 33

What are the steps of 1st signal of recognition of Ag and MHC on APC in t helper and t cytotoxic cells ?

Answer 33

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

Question 34

CD 28 activate B7

Answer 34

False

Question 35

Who will kill cells that doesn't express MHC class 1 ?

Answer 35

NK cells

Question 36

Only Adaptive immune cells have specific Ag receptor , which means that phagocytes and Nk killer's does not have that

Answer 36

True

Question 37

Who produce IL4 and what function does it do ?

Answer 37

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)

Question 38

An immune cell induced by providing flammatory cytokines

Answer 38

Th 17

Question 39

Name CD on NK and which of them are specific

Answer 39

CD 16 CD 56 (specific)

Question 40

NK is activated by

Answer 40

IL 12 from MQ Type 1 IFN ( innate immunity) and IL 2 from Th 1 ( adaptive)

Question 41

NK target

Answer 41

Virally infected cells Cells with IC bacteria Tumors

Question 42

Name all NK receptor

Answer 42

Activating R Inhibitory " IL12 R IL2 R

Question 43

NK pathway Killing is

Answer 43

Perforin

Question 44

T helper 1 is formatted in response to _______ & _______ by _______ produced from _______&______

Answer 44

IC bacteria and viruses IL12 MQ AND DC cells

Question 45

Name the cells that secrete IFN gamma ( type 1 interferon)

Answer 45

T helper 1 NK

Question 46

Function of IFN gamma are

Answer 46

# 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

Question 47

Name the cells that produce IL2 cytokines

Answer 47

T helper 1

Question 48

Name the function of IL2

Answer 48

# + NK and Th , Tc ( t cell growth)

Question 49

Name the cells that produce IL4

Answer 49

Mast cell T helper 2

Question 50

What is the main role of T helper 2

Answer 50

Immunity against helminthic infections

Question 51

What will happen to MQ when IFN gamma activate it

Answer 51

Increase lysosomal protease and ROS and nitric oxide

Question 52

Which cytokines activate eosinophil ? And who produce it

Answer 52

IL5 produced by T helper 2 عملية تصحيح

Question 53

T helper 17 formated in response to _______&________

Answer 53

Fungi Some Extracellular bacteria

Question 54

T helper 17 is activated by

Answer 54

IL 6(proinflammatory] and TGF beta ( from dendritic cell)

Question 55

Who produce IFN GAMMA and name all its function

Answer 55

Produced by NK and t helper 1 Function : # + MQ # production of IgG

Question 56

Who produce IL2 and name its all functions

Answer 56

# + T cytotoxic & T helper cells (T cell growth factor) # + NK