Exam 2: Cellular Immune Response

Question 1

Cellular immune response is provided by which cells

Answer 1

T cells

Question 2

What does the cellular immune response provide immunity to:

Answer 2

intracellular bacteria and viruses, fungi, protozoa, tumors

Question 3

T cells can recognize antigen only when it is presented by which cells?

Answer 3

APC, by self MHC molecules

Question 4

T Cells mediate the process of

Answer 4

activating infected cells and destroying the intracellular organism

Question 5

Endogenous antigen is presented on which MHC molecule?

Answer 5

MHC type 1

Question 6

T Cell cytotoxicity is characterized by:

Answer 6

membrane blebbing, nuclear fragmentation and phagocytosis of the dieing cell

Question 7

initiator caspaces

Answer 7

2, 8, 9, 10, 14

Question 8

Initiator caspaces are activated by

Answer 8

multimoleculular death complexes

Question 9

Effector caspaces

Answer 9

3, 6, 7

Question 10

Effector caspaces function to

Answer 10

break down cellular structures

Question 11

Inflammatory caspaces

Answer 11

1, 4, 5, 11

Question 12

Inflammatory caspaces are activated by

Answer 12

multimolecular inflammasomes

Question 13

Intrinsic pathway of T Cell cytotoxicity (mitochondrial pathway)

Answer 13

1. Damaged mitochondria trigger pathway
2. Cytochrome C triggers formation of apoptosome
3. Initiator caspace 9 is activated
4. Triggers cascade of Effector Caspaces
5. Apoptosis

Question 14

Extrinsic pathway of T cell cytotoxicity (death receptor pathway)

Answer 14

1. TFN-alpha binding Fas triggers pathway
2. Stimulates initiator caspace-8 and 10
3. Triggers cascade of Effector Caspaces
4. Apoptosis

Question 15

What are the major morphological features of cell death by apoptosis?

Answer 15

Normal cell– Clumping of chromatin, blebbing and loss of organelles – Nuclear fragmentation, Apoptotic bodies – Apoptotic bodies

Question 16

T Cell activation requires

Answer 16

1. IL12 from activated DC cell
2. Antigen- MHC complex on abnormal cell
3. IL-2 and IFN-gamma secreted by TH1

Question 17

Perforins function to

Answer 17

create channels in cell membrane

Question 18

Granzymes function to

Answer 18

destroy shit in the cell and activate caspace-3

Question 19

What are the steps in the Perforin Pathway (intrinsic pathway)?

Answer 19

1. Adhesion phase
2. Lethal Hit
3. Cell death

Question 20

What occurs during the adhesion phase of the perforin pathway?

Answer 20

CD8 bind MHC 1, costimulation of T cells and adhesion molecules

Question 21

What occurs during the lethal hit phase of the perforin pathway?

Answer 21

T cell sends granules containing perforins, granzymes

and granulysin; triggering caspace 3, then dna fragmentation

Question 22

What are the steps in the CD95L Extrinsic Pathway?

Answer 22

1. Binding of TCR to MHC 1
2. CD95 L binds CD 95 Fas
3. Formation of DISC-death inducing signaling complex
4. Activates initiator caspace-8 and 10
5. Initates caspace 3
6. Apoptosis

Question 23

What cytokines are secreted by Th1 cells to stimulate antigen presenting cells to kill intracellular bacteria?

Answer 23

IFN- gamma and IL-2

Question 24

Macrophages and DCs phagocytosis and secrete what cytokine to activate NK cells?

Answer 24

IL-12 and TNF alpha

Question 25

Nk cells secrete what cytokine to activate macrophages?

Answer 25

IFN-gamma

Question 26

Full activation of marcophages requires?

Answer 26

Th1 response to IL12 and TNF alpha, to secrete IFN-gamma and IL2 to activate the macrophage

Question 27

Classical activation of macrophages is facilitated by?

Answer 27

TH1 secreting IFN-gamma and TNF alpha, activation M1 macropages

Question 28

M1 macrophages are considered

Answer 28

proinflammatory cells, secreting Il-1, -6, -12, -23, No and iNOS

Question 29

Alternative activation of macrophages is facilitated by?

Answer 29

Th 2 cells and Treg cells secreting IL-4, 10 and 13 to activate M2 macrophages

Question 30

M2 macrophages are considered

Answer 30

antiinflammatory cells, secreting IL-1RA, IL-10 argnizase and TGF beta

Question 31

activated macrophages function to

Answer 31

resolve inflammation, wound repair, extracellular matrix production, cell proliferaiton, angiogenesis

Question 32

What is an effector T cell?

Answer 32

Memory T cells that reside in inflamed tissue and immediately attack invaders

Question 33

Effector Memory T Cell Function

Answer 33

Increase Il-2 receptor, adhesion molecules, IL-4 and IFN-gamma and TCR stimulation
**IL15 survival of Tc memory cell

Question 34

T Cell cytotoxicity induces apoptosis on the target cell by the activation of caspace cascade (Extrinsic and intrinsic pathways). T/F

Answer 34

True

Question 35

The extrinsic and intrinsic pathways triggers a cascade of enzymes activation to induce apoptosis on the target cell. These pathways are activated by the interaction of the T cll receptor and the MHC type 1 and antigen. T/F

Answer 35

True

Question 36

Superantigens

Answer 36

• not MHC restricted -Bind T and APC together

* some stimulate a LG. amount of cytokines that trigger toxic shock syndrome