Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Immunology -- Jones > Exam 1-- Ch.5 T Cells > Flashcards

Exam 1-- Ch.5 T Cells Flashcards

1
Q

What are T cells? Where are they produced? Where do they mature?

A
  • WBCs from bone marrow that mature in the thymus
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Where are T cells found? How many?

A

circulate in blood and lymph (can enter tissue)

–billions!

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What type of receptors to T-cells have? What do they recognize?

A

T Cell Receptors (TCRs)
- “antibody like receptors” (are NOT Ab, like how B-cells have)

  • recognize protein antigens presented by MHCs
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What are the two types of T cells?

A

Killer T cells (aka Cytotoxic T Cells – CTLs)

Helper T cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What activates Killer T cells (CTLs)?

A

by MHC I and abnormal peptide presented on cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

T/F. Very few cells in body can present antigen to CTLs (T Killer Cell) via MHC class I molecules.

A

False– most cells can

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What occurs after the Killer Cell connects to the target cell?

A

triggers apoptosis, for it to commit suicide

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What activated Helper T cells?

A

MHC II and abnormal Antigen Presenting Cells (B-cells, macrophages, or dendritic cells)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What will a T Helper Cell do after it is activated?

A

secrete cytokines

  • interleukin 2 (IL-2)
  • interferon gamma (IFN-gamma)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Recall: Which cells are presenting MHC I? What about MHC II? What does the peptide look like they are presenting? What T cell are they stimulating?

A

MHC I – infected cell presenting endogenous; peptide enclosed; T Killer Cell

MHC II – APC; peptide sticks out; T Helper Cell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What are the three “primary” signals a T cell needs to be activated?

A
  1. T Cell Receptor
  2. Co-Receptor
  3. Co-stimulation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What do these “primary” signals entail for a T-cell to be activated?

  1. T Cell Receptor
  2. Co-Receptor
  3. Co-stimulation
A
  1. TCR must recognize its cognate antigen
  2. co-receptor must recognize the MC (I or II)
  3. other receptor(s) must recognize other molecules
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is the difference b/w a Co-Receptor and Co-Stimulation?

A

Co-receptor is recognizing the MHC (I or II)

Co-stimulation means recognizing other molecules

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What occurs if the T cell’s TCR recognizes MHC plus self peptides?

A

the T-cell commits suicide (apoptosis)

– (T cells created that would kill self need to go away)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What occurs if the T-cell’s TCR recognizes cognate antigen(non-self) on MHC with no co-stimulation?

A

T cell is anergized (inactivated)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What occurs if the T-cell’s TCR recognizes cognate antigen on MHC plus there is co-stimulation?

A

T cell is activated

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

T/F All T-cell TCRs only recognize peptides presented by MHC I and MHC II molecules.

A

True

18
Q

What are the two types of TCRs?

A
  1. alpha-beta (95%) –traditional

2. gamma-delta –non-traditional

19
Q

T/F. All TCrs on a given mature T cell are usually different.

A

False– they are usually ALL identical!!!

20
Q

What is the name given to the group of signaling proteins ass. with TCR?

A

CD3

21
Q

What are the elements needed for a T-cell to be activated?

A
  1. Recognition (TCR–alpha-beta; and Co-receptor–CD4 or CD8)
  2. Co-stimulation (B7 on APC; and CD28 on T-cell)
  3. Signaling (CD3; and CD28 on T-cell)
22
Q

What is the TCR proteins (alpha-beta) needed for?

A

antigen recognition

23
Q

What is the co-receptor needed for?

A

the co-receptor = CD4 or CD8–(on T-cell); are for MHC recognition

24
Q

What are the co-stimulatory molecules?

A

B7 proteins on APC

25
Q

What is CD3 needed for?

A

signaling

or those other 4 proteins– weird symbols

26
Q

What type of T-cell expresses CD4? What MHC is then involved? What type of signal is created?

A

Helper T cells; attaches TCR to MHC II molecules

HELP signal

27
Q

What type of T-cell expresses CD8? What MHC is involved? What type of signal is created

A

Killer T Cells (CTLs); attaches TCR to MHC I molecules

KILL signal

28
Q

What are the two kinds of Co-receptors of T-cells?

A

CD8 —> is MHC I restricted (peptides in cell)

CD4–> implies MHC II (peptides from outside cell)

29
Q

What do the co-receptors do for T-cells? Why are they important?

A

Co-receptors bind T cells to MHCs (Type I or II)

w/o them the T-cell would not know if an APC is presenting protein fragments and need help (helper T) or if an APC is infected and needs to be killed (killer T)

30
Q

What can created the Co-stimulation of T-cells?

A

many moelcules!

- B7 proteins (CD80, CD86) from APC’s, connect with CD28 receptor on T-cell

31
Q

What is B7? What is CD28? What occurs when CD28 is activated?

A

B7–> is a co-stimulatory molecule expressed on surface of APCs

CD28–> is a receptor molecule on T-cell; when activated it amplifies signal and lowers number of TCR crosslinks needed for activation

32
Q

What are Helper T cells constantly doing in the lymph nodes?

A

scanning dendritic cells; if find cognate antigen it will:

  • TCR engages antigen/MHC
  • CD4 co-receptor on Helper T cell attaches to MHC II on dendritic cell
  • CD40L proteins attach to CD40 on dendritic cell
  • dendritic cell makes co-stimulatory molecules (B7)
  • adhesion molecules bind two cell together (immunological synpase)
33
Q

Once the Helper T cells are fully activated and bound to the dendritic cells, what happens next?

A

Helper T cell and APC part ways

  • Helper T proliferates and makes more IL-2
  • APCs goes on to activate other Helper T cells
34
Q

What does IL-2 serve as for Helper T cells?

A

a positive feedback for division

35
Q

Do naive T cells have IL-2 receptors on their surface? What does this results in?

A

No, therefore only T cells replicating are specific ones needed to combat the particular antigen

36
Q

How are Killer T cells activated?

A

only need an activated dendritic cell for activation

37
Q

What is the process of a Killer T cell becoming activated?

A
  • Naive CTL meets activated DC presenting cognate antigen on a MHC I
  • Co-receptors and co-stimulation occur (CD8 on Killer T cells binds to MHC I)

(same concept as helper T cells)

38
Q

How long to dendritic cells and Helper T cells bind for? What occurs during this time?

A

for hours

- emit cytokines which attract CTLs

39
Q

Which cell is in charge of supplying IL-2 for CTL proliferation? What cell regulates magnitude of CTL response?

A

Helper T cells!!

40
Q

What are non-traditional T cells?

A
  • T cells that express gamma-delta receptors
  • are Natural Killer T cells (somewhat b/w T cells and NK cells)
  • have traditional alpha-beta receptors
41
Q

Where are Non-Traditional T cells most abundant?

A
  • intestine
  • uterus
  • tongue
42
Q

What do non-Traditional T cells recognize?

A

lipid antigens presented by non-traditional MHC- called CD1

Immunology -- Jones (14 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions