Immunology 8: T Cell Mediated Immune Responses

Front 1

activation of T cells requires what kind of cell?

Back 1

APC- antigen presenting cells ( express MHC)

Front 2

T cell response are directed towards what kind of invader

Back 2

intracellular pathogens

Front 3

2 types of T cells

Back 3

cytotoxic
Th1

Front 4

cytotoxic

effector T cell
antigen recognition
action

Back 4

Cytotoxic CD8 T cell
peptide-MHC Class I complex on infected cell
kill infected cells

Front 5

Th1
effector T cell
antigen recognition
action

Back 5

Th1 cell
peptide-MHC Class II complex on macrophages
activate infected macrophages

Front 6

humoral immnity

effector T cell
antigen recognition
action

Back 6

TH1 and Th2
peptide-MHC Class II complex on antigen specific B cell
activation of specific B cell to make antibody

Front 7

What cytokine drives T cell production?

Back 7

IL-2

Front 8

2 interactions that stimulate decline of T cells

Back 8

Fas- FasL
TNFalpha- TNF receptor

Front 9

What downregulates the decline of T cells?

Back 9

FLIP

Front 10

purpose of dendritic cells

Back 10

transport antigens from periphery to lymphoid organs where T cells become activated following antigen presentation

Front 11

APC in lymph nodes

Back 11

dendritic cells
macrophages
B cells

Front 12

where dendritic cells are found in lymph node

Back 12

cortex

Front 13

here macrophages are found in the lymph node

Back 13

marginal sinus
meduallary cords

Front 14

where B cells are found in the lymph nodes

Back 14

follicles

Front 15

purpose of immature dendritic cells

Back 15

facilitates phagocytosis of antigens in peripheral tissues

Front 16

purpose of mature dendritic cells

Back 16

stimulate T cells

DC-SIGN

Front 17

how do pathogens induce expression of important APC molecules?

Back 17

most APCs express little MHC and costim molec

after phagocytosis, they are degraded and relase molec that lead to an innate reponse.

innate response is necessary for an adaptive response

binding of microbrial degradatin productions leads to an increase in MHC and costim molec

Front 18

two fates for T cells in lymph nodes

Back 18

1. don't encounter antigen. They are returned to the blood stream

2. if encounter antigen, are retained in the lymph node. proliferate and differentiate into effector cells

Front 19

purpose of leukocyte adhesion molecules

Back 19

act to direct migration of leukocytes to specific areas of the body

act as costimulatory molecules that are directly involved in the activation of specific leukocyte cell types

Front 20

L-selectin

Back 20

a leukocyte adhesion molecule in naive T cells that binds to either GlyCam-1 or CD34 expressed on the HEV that allows them to leave blood and enter peripheral lymphoid tissues

--non specific, non activated situation

Front 21

HEV

Back 21

HEVs enable naïve lymphocytes to move in and out of the lymph nodes from the circulatory system.

Front 22

diapedesis

Back 22

leaving the vessel

Front 23

MadCam-1

Back 23

on mucosal endothelium

can bind to L selectin that is bound to T cell and allows them to leave blood and enter mucosal lymphoid tissue of gut

Front 24

process to cross HEV

Back 24

1. L-selectin binds to Glycam-1 and CD34 which enables rolling interaction

2. LFA-1 is activated by chemokines

3. activated LFA-1 binds tightly to ICAM-1

4. diapedesis

ICAM and LFA-1 stabilize

Front 25

LFA-1 is an

Back 25

integrin that is expressed on all leukocytes and binds to ICAM-1 on APC

Front 26

LPAM-1 is an adhesion

Back 26

that is on a subset of naive cells and minds to MAdCAM-1 on the mucosal endothelium

Front 27

VLA-4 is an

Back 27

integrin that is on activated effector T cells that binds to VCAM-1 on endothelium

VCAM is upregulated at the site of inflammation. VLA4 on the T cells will bind to it and let it know where the T cell can be found

Front 28

steps in antigen presentation

Back 28

1. T cell binds APC through LFA1-ICAM-1 (slows down T cell rolling so it can pay attention to what is going on with dendritic cells- sampling peptide bound to MHC)

2. this allows for other T cell receptors to be bound

3. conformational change in LFA-1 increases affinity and prolongs cell-cell contact

Front 29

T cell activation

Back 29

2 signals needed

1. MHC ClassII w/ antigen -- TCR along with CD4/ CD8

2. CD28 (T)- CD80(APC)

Front 30

How does the T cell signal get transduced?

Back 30

release of Ca after receptor engagement

Front 31

ex of how the innate immune response potentiates the later adaptive immune respons

Back 31

the phagocytosis and breakdown of bacteria by macrophage induces expression of MHC ClassII and CD80

Front 32

adjuvants

Back 32

microbial products known to increase T cell responses

if on APC next to bacteria, will co-stim T cells

Front 33

Is costim signal (Cd28-CD80) needed for both naive and effector T cells?

Back 33

No, only for naive

Front 34

B cells as APCs

Back 34

antigen derived presented on surface of B cell

need 2 signals

CD40-CD40L
CD28-CD80

Front 35

CTLA-4

Back 35

on T cell, binds to CD80 to shut down proliferation of t cell

Front 36

VLA-4

Back 36

controls migration of effector T cells

expressed on activated T cells

interacts with VCAM-1 which is expressed on endothelium of blood vessels in inflamed tissue

Front 37

naive vs activated T cells and IL-2

Back 37

naive have low affinity IL-2 R
activated have high affinity IL-2R and they also secrete IL-2 which stimulates proliferation of T cells

Front 38

function of Th1 cells

Back 38

macropahge activation
B cell activation
production opsonizing antibodies such as Ig1

Front 39

function of Th2 cells

Back 39

general activation of B cells to make antibodies

Front 40

where do Th1 and Th2 cells come from?

Back 40

CD 4 T cells

Front 41

pathway of Th1 and Th2 cell production

Back 41

maive CD4 T cell + APC--> proliferating T cell

cytokine IFN gamma induces TF Tbet which activates transcription of TF STAT4. STAT4 is activated by IL-12 --> Th1

cytokine IL4 induces GATA-3 which turns into STAT6 which with IL-4 --> Th2

Front 42

if equal amt of IL12 and 4 in production of T helper cells, which cell will result?

Back 42

Th2

Front 43

What cytokines does Th1 produce?

Back 43

IFN gamma, IL3

Front 44

What cytokines do Th2 produce?

Back 44

IL 3, 4, 5, 10, 13

no IFN gamma

Front 45

cytotoxic effecotr molec

Back 45

perforin
granzymes
granulysin

Front 46

main function of CD8 T cell

Back 46

cytotoxic T cell

Front 47

main function of CD4 T cell, Th1

Back 47

activate macrophage

Front 48

main fxn of CD4 T cell Th2

Back 48

produce antibodies

Front 49

effector function of Th1 cell

Back 49

produce IFN gamma which acts on:

activate macrophage to kill intracellular pathogens

B cells to stimulate IgG that oposonize microbes for phagocytosis

produce LT and TNF to activate nuetrophils and stimulate inflammation

Front 50

how is the activation of macrophages controlled?

Back 50

by inhibiting activated macrophages

Th2 cells relase cytokines GF, IL4, IL10, IL13

these cytokines also reduce Th1 production of IFN gamma which reduces Th1 direct effects on macrophages

Front 51

granuloma

Back 51

bunch of bacteria surrounded by T cells in order for containment

Front 52

effector functions of Th2 cells

Back 52

produce IL4 that stimulate B cells to produce neutralizing IgG and IgE

produce IL5 that activates eosinophils

produce IL10 and IL4 to suppress activated macrophages

Front 53

what chenokines are importnat in regulation of T regulatory cells?

Back 53

IL10

TGF-beta (lead to development of T regulatory and effector cells)

Front 54

do effector T cells require costim?- consequence

Back 54

nope

can kill any cell that expresses target antigen on MHC molec

Front 55

2 mechanisms of CTL killing

Back 55

1. granzymes enter through perforin holes on T cell --> activation of capsases --> apoptosis

2. Fas- FasL

Front 56

specificity of CTL response vs macrophage response

Back 56

CTL response is targeted, activated macrophages are not specific- there will bebystander damage

Front 57

perforin

Back 57

pore spans entire membrane to allow entry of granzymes

Front 58

cytokines that CTL cells make

Back 58

IFN gamma, TNF gamma, TNF beta

Front 59

purposes of IFN gamma

Back 59

increase MHC expression and make targets more visible
inhibits viral replication directly
activates macrophages

Front 60

function of TNF

Back 60

activates macrophages
kills through TNFR-1

Front 61

cognate interaction

Back 61

B and T cell recognize same antigen.

helps with vaccines