Cytotoxic Cell mediated immune responses

Question 1

Before arriving at CD4+/CD8- and CD8+/CD4- cells, describe the first four cellular stages of the lymphocyte

Answer 1

Stem cell –> Double negative (CD4-/CD8-) –> Pre-T cell –> Double positive (CD4+/CD8+) –> 4 possible outcomes

Question 2

4 possible outcomes for lymphocytes during selection

Answer 2

strongly recognize Ag-APC –> apoptosis (negative selection)

no recognition Ag-APC—> apoptosis (negative selection)

Weak recognition Ag-APCE –> CD4+/CD8- and CD8+/CD4-

Question 3

Where does Ag-independent maturation of the T cell occur?

Answer 3

only in the thymus

Question 4

Thymocytes do what

Answer 4

serve as professional APCs but present BOTH MHC II and MHC I with antigens

Question 5

activation of T cells occurs in the

Answer 5

LN

Question 6

Langerhans cells are

Answer 6

immature DCs which do not express B7. found in the epithelia

Question 7

When do Langerhans cells express B7?

Answer 7

in the LN

Question 8

what kind of Langerhan cell stimulates naive T cell?

Answer 8

B7 positive

Question 9

DCs enter the lymph node via the _____ and present AG to naive T cell located in the _______.

Answer 9

afferent lymphatic vessel

parafollicular cortex

Question 10

CD4/CD8 cells dual function

Answer 10

1) they help FIND the right MHC
2) they help stabilize, “clip” onto the MHC

remember, CDs are signaling coreceptors

Question 11

B7-CD28 stimulation

Answer 11

co-stimulatory that amplifies the signal

Question 12

Signal 1 and signal 2

Answer 12

1) Ag-TCR rec
2) B7-CD28 rec
- –> proliferation of T cells specific for bacteria

Question 13

Activated T cells secrete what to stimulate their own proliferation? The number is increased every ____ hours

Answer 13

IL-2, autocrine stimulation

doubles

Question 14

APC presents Ag: what are the three subsequent events

Answer 14

1) Activation leads to expression of IL-2R and autocrine IL-2 signaling for proliferation
2) APC detaches before proliferation

NOTE: THEY ARE NOT DIFFERENTIATED YET

Question 15

in what order is activation, proliferation, and differentiation in?

Answer 15

the one in the question

activation (Ag recognition, followed by IL-2R/IL-2 expression)

proliferation (brought on by IL-2 signaling)

RE-STIMULATION by Ag initiates differentiation

Question 16

Re-stimulation is required for?
Where does re-stimulation occur?
What cell is responsible for re-stimulation?

Answer 16

differentiation
HOMING: the T cell goes to the tissue from which the Ag was presented in order to be re-stimulated by

tissue macrophages

Question 17

Steps from naive CD4 T (uncommitted) to fully differentiated TH1/TH2 cell

Answer 17

Naive T cell (uncommitted) + Ag-APC –> Prolif. T cell

Immature effector cell (Th0) + cytokine —> Th1/Th2

Question 18

differentiation is also called

Answer 18

commitment

Question 19

restimulation leads to

Answer 19

commitment

Question 20

Microenvironment includes

Answer 20

macrophages and their secretory products

Question 21

Why is the microenvironment important

Answer 21

it controls the functional commitments of the T cells

Question 22

microenvrionment is also called the

Answer 22

cytokine field

Question 23

the presence of macs and IL-12 drives the Th0 toward
the presence of macs and IL-4 drives the Th0 toward
The absence of IL-12 drives

Answer 23

Th1
Th2
Th2, not necessarily requiring IL-4

Question 24

Costimulation 1
Costimulation 2

what does the second co-stimulation do?

Answer 24

1 = CD28 --- B7 (APC)
2 = CD40L -- CD40 (APC)

2 increased the expression of MHC and B7

Question 25

Upregulation of what CD marker is required for B cell activation?

Answer 25

CD40L

Question 26

To recap: Th1 ---> outcomes Th2 --> outcomes

Answer 26

Th1 1) Activates macrophages 2) B cell stimulation --> IgG --> complement and opsonization Th2 1) stimulation of IgE via IL-4--> mast cell degranulation 2) activation of eosinophils via IL-5 (helminth fighting)

Question 27

Activation of CD8 cells is done via

Answer 27

cross presentation in the LN DC-Ag presentation just like CD4s activated CD8s proliferate AND THEN leave the LN

Question 28

There are three forms of CD8 activation

Answer 28

1) Stimulation+costimulation of CD8 cell without CD4 help 2) Stimulation+costimulation of CD8 with CD4 assistance 3) Stimulation+costimulation of MAC by CD4; Mac goes on to activate CD8s

Question 29

Three ways CD8 kills infected cells

Answer 29

1) Degranulation of perforin and granzyme 2) Fas-L-Fas (CD95) induced apoptosis 3) IFN-gamma activated MACs

Question 30

(gamma-delta) T cells. Function:

Answer 30

1) first line of defense 2) regulatory cell 3) bridging innate and adaptive responses

Question 31

(gamma-delta) T cells. Location

Answer 31

uterus, tongue, intestine

Question 32

(gamma-delta) T cells. Recognition complex

Answer 32

includes gamma-delta TCR and CD3

Question 33

What parts of the nontraditional T cell are considered adaptive and what parts are considered innate?

Answer 33

the adaptive = rearrangement of TCRs, development of a memory phenotype the innate = uses TCR like a PRR they dont need APCs, and they are not MHC restricted

Question 34

Slide number 28 has 6 interesting functions listed.

Answer 34

``` lysis of infected cell apc for alpha-beta t cells helps B cell and IgE production dendritic cell maturation regulation of stromal cell via growth factor production cytokine/chemokine production ```

Question 35

(gamma-delta) T cells. Location

Answer 35

uterus, tongue, intestine

Question 36

(gamma-delta) T cells. Recognition complex

Answer 36

includes gamma-delta TCR and CD3

Question 37

What parts of the nontraditional T cell are considered adaptive and what parts are considered innate?

Answer 37

the adaptive = rearrangement of TCRs, development of a memory phenotype the innate = uses TCR like a PRR they dont need APCs, and they are not MHC restricted

Question 38

Slide number 28 has 6 interesting functions listed.

Answer 38

``` lysis of infected cell apc for alpha-beta t cells helps B cell and IgE production dendritic cell maturation regulation of stromal cell via growth factor production cytokine/chemokine production ```

Question 39

(gamma-delta) T cells. Location

Answer 39

uterus, tongue, intestine

Question 40

(gamma-delta) T cells. Recognition complex

Answer 40

includes gamma-delta TCR and CD3

Question 41

What parts of the nontraditional T cell are considered adaptive and what parts are considered innate?

Answer 41

the adaptive = rearrangement of TCRs, development of a memory phenotype the innate = uses TCR like a PRR they dont need APCs, and they are not MHC restricted

Question 42

Slide number 28 has 6 interesting functions listed.

Answer 42

``` lysis of infected cell apc for alpha-beta t cells helps B cell and IgE production dendritic cell maturation regulation of stromal cell via growth factor production cytokine/chemokine production ```