T cells 2 Part 1

Question 1

What do Tk cells do?

Answer 1

kill other cells

Question 2

What do Th cells do?

Answer 2

help other cells

Question 3

Where are T cells made?

Answer 3

bone marrow

Question 4

Where do T cells mature?

Answer 4

in the thymus (T for thymus)

Question 5

T/F: T cells circulate in the blood and lymph.

Answer 5

true

Question 6

T/F: T cells cannot enter tissue

Answer 6

false; they can

Question 7

What are the antibody like receptors on the surface of T cells called?

Answer 7

T cell receptors (TCRs)

Question 8

What do TCRs specialize in?

Answer 8

recognizing protein antigens presented by MHCs (this means the antigen is a peptide)

Question 9

T/F: there are about 300 million T cells in the body on average.

Answer 9

False; 300 billion, with a B.

Question 10

What are killer T cells also called?

Answer 10

cytotoxic T cells (CTLs)

Question 11

How are killer T cells activated?

Answer 11

by MHC I being presented on cells

Question 12

T/F: most cells in the body can present antigens to CTLs via MHC class II molescules.

Answer 12

False; should say MHC I molecules

Question 13

What connects to the target cell and triggers it to commit suicide killing the cell and the virus inside it?

Answer 13

Killer T cells/CTLs

Question 14

What activates Helper T cells (Th)?

Answer 14

MHC II on Antigen Presenting Cells (APCs)

Question 15

What is secreted by Helper T cells?

Answer 15

cytokines IL-2 and IFN-y (interferon gamma)

Question 16

What kind of cells keep the immune system from overreacting?

Answer 16

Regulatory T cells

Question 17

T/F: regulatory T cells are probably the one part of the immune system that we know the most about.

Answer 17

False; much is still unknown about regulatory T cells

Question 18

T/F helper T cells do not require activation to perform their function.

Answer 18

False; both helper and killer T cells require activation

Question 19

What kind of cells help Helper T cells?

Answer 19

APCs (activated dendritic macrophage and B cells)

Question 20

What must a TCR recognize in order to be activated?

Answer 20

cognate antigen

Question 21

What must the Co-receptor recognize in order for activation to occur?

Answer 21

MHC (either I or II)

Question 22

What happens during Co-stimulation?

Answer 22

other receptors recognize other molecules (besides for cognate antigens and MHCs)

Question 23

T/F: more is known about Helper T cell activation than Killer T cell activation.

Answer 23

True (think alphabetical order)

Question 24

What happens to T cells that see “self” being presented by other cells?

Answer 24

These die. T cells that would kill self need to go away.

Question 25

How are T cells anergized?

Answer 25

When T cells recognize self antigen, but do not get co-stimulated they will be rendered inactive or anergized.

Question 26

What happens to a T cell that sees non-self and gets co-stimulated?

Answer 26

activation

Question 27

What happens when a TCR recognizes MHC plus self peptides?

Answer 27

T cell commits suicide (apoptosis)

Question 28

What happens when TCR recognizes cognate antigen on MHC with no co-stimulation?

Answer 28

T cell is anergized (inactivated)

Question 29

What happens when TCR recognizes cognate antigen on MHC plus co-stimulation?

Answer 29

T cell is activated

Question 30

T/F: T cells recognize MHC I and/or MHC II molecules.

Answer 30

False; T cells only recognize peptides presented by MHC molecules

Question 31

T/F: TCRs are more diverse than BCRs.

Answer 31

False; BCRs are more diverse

Question 32

T/F: All TCRs on mature T cells are identical except for a few exceptions.

Answer 32

True

Question 33

What are the two types of TCRs?

Answer 33

traditional (alpha beta) ad non-traditional (gamma delta)

Question 34

T/F:about 95% of TCRs are alpha beta TCRs.

Answer 34

True; the other 5% are gamma delta)

Question 35

What is the name given to the group of signaling proteins?

Answer 35

CD3

Question 36

What kind of receptors are expressed by non-traditional T cells?

Answer 36

gamma delta receptors

Question 37

Where are non-traditonal T cells most abundant?

Answer 37

in the intestine, uterus and tongue

Question 38

T/F: non-traditional T cells have more diversity than the alpha beta receptors (traditional T cells).

Answer 38

False; they less diversity

Question 39

T/F: non-traditional T cells are more effective at recognizing protein fragments from invaders.

Answer 39

True, at least around the intestine uterus and tongue they are

Question 40

T/F: more is known about non-traditional T cells than the traditional T cells.

Answer 40

False; less is known about non-traditonal Tcells

Question 41

Why are TCR proteins important for actviation?

Answer 41

antigen recognition

Question 42

Why are co-receptor proteins (CD4 or CD8) needed for activation?

Answer 42

MHC recognition

Question 43

What co-stimulatory molecules are needed for activation?

Answer 43

B7 proteins on APCs

Question 44

Why are CD3/CD4 proteins needed for activation?

Answer 44

for signaling

Question 45

Why is CD28 on Tcells important for activation?

Answer 45

co-stimulation and signaling

Question 46

Where is the T cell co-receptor CD4 usually expressed?

Answer 46

on helper T cells

Question 47

What kind of molecule does CD4 attach the TCR to?

Answer 47

MHC II molecules

Question 48

Where is the T cell co-receptor usually expressed?

Answer 48

on Killer T cells (CTLs)

Question 49

What kind of molecules does CD8 attach the TCR to?

Answer 49

MHC I molecules

Question 50

T/F: CD8 signals "likely to help"

Answer 50

False; this is what CD4 signals, CD8 signals "likely to kill"

Question 51

T/F: Without the co-receptor, the T cell would not know if an APC is presenting protein fragments and needs help (helper T) or if an APC is infected and need to be killed (killer T)

Answer 51

True

Question 52

T/F: MHC I molecules are eaten by the APC.

Answer 52

False; this is true of MHC II molecules

Question 53

T/F: MHC I molecules are peptides being made in the cell.

Answer 53

True

Question 54

What is implied by the CD8 co-receptor?

Answer 54

MHC I

Question 55

What is implied by the CD4 co-receptor?

Answer 55

MHC II

Question 56

T/F: CTLs bind to kill.

Answer 56

True

Question 57

What do B cells, Dendritic cells, and macrophages have in common?

Answer 57

These are all APCs

Question 58

MHC presents the antigen (peptide) which is recognized by the TCR. What recognizes the MHC? And what sends a signal of this to the nucleus of the T cell?

Answer 58

co-receptor; CD3

Question 59

T/F: B7 is a receptor molecule on the T cell. When activated, it amplifies the signal and lowers the number of TCR crosslinks needed for activation.

Answer 59

False; this is true of CD28; B7 is a co-stimulatory molecule expressed on the surface of APCs.

Question 60

What does the combination of co-stimulation molecules depend upon?

Answer 60

the pathogen and the area of the body (regional identity)

Question 61

T/F: the connection between the receptor and the nucleus of naiive T cells is weak.

Answer 61

true; activation with co-stim creates a better connection.

Question 62

Once T cells are activated by co-stimulation, many more cholesterol lipid rafts form. What do these lipid rafts contain?

Answer 62

large numbers of signaling molecules

Question 63

T/F: experienced T cells have few rafts.

Answer 63

False; experienced T cells have many, naive T cells have few.

Question 64

What is the benefit of Experienced T cells maintaining the lipid rafts?

Answer 64

they don't need co-stim for reactivation

Question 65

What is easier, Reactivation or co stimulation?

Answer 65

reactivation because the raft has formed

Question 66

Dendritic cells may first activate T cells in a lymph node. What re-stimulates/activates T cells once they reach the battle site?

Answer 66

Macrophages