T Cell Activation And Function

Front 1

What is the protein that is lateral to the TCR and is responsible for signal transduction?

Back 1

CD3

Front 2

What is the structure of MHCI's?

Back 2

alpha chain with 3 external domains, 1 transmembrane domain, and 1 cytoplasmic tail. Beta 2 microglobulin chain with one external domain. Beta 2 is not encoded in MHC gene

Front 3

What is the structure of MHC2's?

Back 3

alpha chain has 2 external domains, 1 transmembrane, and 1 cytoplasmic tail. Beta chain has the same number and type domains as alpha. All are encoded in the MHC gene.

Front 4

where is the peptide Ag binding cleft in MHC1's and MHC2's?

Back 4

1: between alpha 1 and alpha2
2: between alpha 1 and beta 1

Front 5

What are the three gene regions that encode MHC2's?

Back 5

DP, DQ, and DR. (each contains an alpha and beta chain)

Front 6

What are the three regions in the MHC1 gene?

Back 6

B, C, A (only alpha chains).

Front 7

which cells can present intracellular protein Ag or extracellular protein Ag to either MHC class (it breaks the rules)?

Back 7

dendritic cells

Front 8

what are the protein transporters that transport intracellular Ag from the proteosome to the ER to be presented on MHC1's?

Back 8

tap1 and tap2

Front 9

what part of the CD3 protein is responsible for signal transduction?

Back 9

Itam's

Front 10

alpha chains on the TCR have what DNA segments? beta chains??

Back 10

alpha: V and J
beta: V,D, and J

Front 11

Where are the gamma and delta loci for g-d TCR?

Back 11

gamma: different chrom (chrom 7)
delta: in between V-alpha and J-alpha

Front 12

What are two examples of non specefic adhesion molecule interactions seen when the TCR and MHC associate?

Back 12

LFA1 (on T cell) binds ICAM1
CD2 (on T cell) binds LFA3

Front 13

In the thymus, corticoepithelial cells mediate positive selection in what type of immature T cells?

Back 13

double positive thymocytes (have both CD4 and CD8)

Front 14

In the thymus, dendritic cells in the cortico-medullary junction mediate negative selection in what stage of T cell maturation?

Back 14

double positive thymocytes (CD4 and CD8 positive) OR mature (either CD8+ OR CD4+) thymocytes

Front 15

What is the progression of CD44 and CD25 seen in maturing double negative thymocytes before they enter the double positive stage?

Back 15

CD44+, CD25-
CD44+, CD25+
CD44low, CD25+
CD44-, CD25-

Front 16

In terms of TCR receptor alpha chain and beta chain DNA rearrangement, which one rearranges 1st and what DNA regions does it rearrange first?

Back 16

B chain rearranges first. It rearranges segments DJ first then V.

Front 17

The mature TCR is seen first at what maturation stage of the T cell?

Back 17

the double positive stage

Front 18

Why can't T cells bind free Ag?

Back 18

Because positive selection makes them bind self MHC + peptide

Front 19

T cell maturation looks a lot like B cell maturation except for what process?

Back 19

B cells undergo somatic hypermutation to change their binding speceficities, whereas T cells do not.

Front 20

What is the main co-stimulatory signal seen in T cell activation?

Back 20

Association of CD28 on T cell with its ligand, B7

Front 21

What are the 2 competence signals in T cell activation and what is the progression signal?

Back 21

competence signals are the TCR engagement and the co-stimulatory signal. The progression signal is IL-2R and IL-2.

Front 22

What is the signalling pathway activated by the competence signal in T cell activation?

Back 22

CD45 (membrane protein) de-Pi's SARC family kinase (Fyn or LCK) which Pi ITAMs (docking sites on CD3) which $'s ZAP70 which $'s PLC. DAG $'s PKC which removes IK-B from txn factor NF-KB. IP3 releases Ca2+ which $'s calmodulin which de-Pi's NF-ATc thus activating this txn factor. The genes upregulated are for IL-2 and IL-2R

Front 23

If a naive T cell encounters an APC with MHC + Ag but NO co-stimulatory signal, what happens?

Back 23

The T cell becomes anergic leading to tolerance to that Ag.

Front 24

What are the cytokines secreted by the TH1 cells?

Back 24

IL-2, IFN-y, TNF-B, GM-CSF, IL-3

Front 25

What two cytokines promote TH1 formation?

Back 25

IL-12 from dendritic cells exposed to bacteria and viruses and IFN-y from NK cells which make IFN-y in presence of IL-12

Front 26

What cytokine promotes TH2 formation and what conditions promote its release?

Back 26

IL-4, which is secreted from NK cells in absence of dendritic cells.

Front 27

TH1's secrete what to prevent TH2 formation, and TH2's secrete what to prevent TH1 formation?

Back 27

TH1's secrete IFN-y
TH2's secrete TGF-B and IL-10

Front 28

What do these cytokines do? (answers in the same order)
IFN-y, TNF-B or FASL, IL-3 + GM-CSF, TNF-a and TNF-B.

Back 28

activates macs, kills chronically infected cells and macs to release contents to new macs, induces mac differentiation in bone marrow, and upregulate adhesion molecules in the endothelium for diapdesis of macs

Front 29

B cells present antigen to T cells via which MHC class?

Back 29

MHCII

Front 30

TH2's activate B cells via what signalling molecules?

Back 30

CD40 on B cell and CD40L on T cell

Front 31

If a CD4 T cell does not assist the APC in activating a naive T cell to become a CD8, what is the consequence?

Back 31

There will be no memory cells from this event

Front 32

Graft rejections are what kind of response?

Back 32

Delayed type hypersensitivity response or type 4 response

Front 33

Where do super antigens bind on MHC II's? On TCR?

Back 33

alpha 1 chain on MHC and V beta section of TCR

Front 34

What is a genetic advantage some people have over toxic shock syndrome toxin (a super antigen)?

Back 34

They do not have V beta2 regions on their TCR where this toxin binds.