Lecture 13 Ch. 10 Flashcards Preview

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Flashcards in Lecture 13 Ch. 10 Deck (114)
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1

Specific T cells are made by the immune system "____"

On demand

2

Approximately 1 in 10^__ T cells has a specific TCR that can recognize a given pathogen.

6

3

The T cell whose TCR recognizes a given invader does what?

becomes mobilized and activated

4

Over __-__% of T cells in the circulation have αβ TCRs

90-95

5

The α/β TCRs recognize (bind to) peptides presented within what?

The MHC molecules and the MHC itself

6

α/β TCRs also express either ____ or ____ co-receptors.

CD4 or CD8

7

Ag recognition involves what?

clustering of TCRs

8

Activation of T cells is initiated by what?

A signaling cascade after TCRs (at least two) recognize specific Ag.

9

The α and β chains have only a very short _____ _____.

Intracellular domain

10

Signaling is mediated by other proteins comprising _____ _____.

TCR complex

11

What have cytoplasmic tail that is long enough to signal?

CD3 proteins γ, δ, ε, and ζ

12

What is needed to activate a T cell?

TCR, CD4 or CD8, and CD3

13

CD3 is a marker for counting total numbers of what?

T cells (CD4+ CD8 T cells)

14

Langerhans' cells are immature DCs which do not express what?

High levels of B7

15

Activated DC can "interview" how many naive T cells per hour?

500

16

Langerhans' cells enter the lymph node to become what?

Dendritic cells expressing B7

17

B7-positive dentritic cells stimulate what?

Naive T cells

18

When the TCR is engaged and activated T cell, what must happen to the T cell?

T cell must receive a co-stimulatory signal

19

What co-stimulatory molecules are expressed on professional APC?

B7 proteins (CD80/CD86)

20

B7 molecules plug into what?

CD28 receptor expressed on T cells

21

Co-stimulation can be considered as what?

an amplifier that improves the signal

22

With co-stimulation, ~_____-____ fewer of clustered TCRs are needed for activation

100-fold

23

After activation is completed, what happens to the T helper cell and APC?

They are separated.

24

After APC activates a T cell it goes on to do what?

Activate other T cells

25

T cell proliferate in order to do what?

increase their numbers

26

The proliferation of T cells is driven by what?

IL-2, also called "T cell growth factor"

27

What do naive T cells not have expressed on their surface?

IL-2 receptor (IL-2R)

28

Activated T cells produce large amounts of what and express what?

IL-2 and express IL-2R

29

What does IL-2 enhance?

Resistance of activated T cells to apoptosis

30

Th1, Th2 and Th17 cells are all ....

CD4-positive helper cells