Immunology Test II T-Cells Flashcards

1
Q

T cells populate the ________ lymphoid organs and tissues.

A

peripheral

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2
Q

T cells are ________ lived

A

long

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3
Q

T cells make up ______ % of all recirculating lymphocytes

A

80%

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4
Q

T cells acquire antigen-specific receptors in the ______

A

Thymus

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5
Q

Cell surface proteins of T cells are involved in ______ recognition.

A

antigen

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6
Q

Cell surface proteins of T cells are involved in ______ transduction.

A

signal transduction

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7
Q

Cell surface proteins of T cells are involved in ______ to APC’s and target cells

A

adhesion

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8
Q

What are the accessory molecules of T-cells?

A

CD4
CD8
Lymphocyte Adherence Molecules
CD28

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9
Q

What are the TCR coreceptors?

A

CD4 and CD8

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10
Q

What do CD4 and CD8 promote?

A

Adhesion of T-cells to APCs and target cells

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11
Q

______ is found on helper T cells.

A

CD4

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12
Q

______ is found on cytotoxic T cells

A

CD8

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13
Q

______ binds to β2 domain of class II MHC molecule on surface of pro APC’s

A

CD4

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14
Q

______ recognize the α3 domain of class I MHC molecules

A

CD8

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15
Q

_____ is on monocytes and macrophages

A

CD4

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16
Q

What are the functions of Lymphocyte Adherence Molecules?

A

Strengthen interactions between helper T cells and pro APCs

Strengthen interactions between cytotoxic T cells and target cells

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17
Q

CD11aCD18 and CD2 are examples of what kind of molecule?

A

Lymphocyte Adherence Molecules

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18
Q

What is the T cell receptor for co-stimulation?

A

CD28

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19
Q

What does CD28 bind to?

A

B7-1 and B7-2 on pro APCs

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20
Q

What does the TCR Complex consist of?

A
  1. T-cell receptor
  2. CD3 Complex
  3. ζ proteins
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21
Q

What is a a heterodimeric glycoprotein that allows T cells to recognized processed antigens that is always presented with MHC molecules

A

TCR Complex

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22
Q

T or F. The TCR Complex can perform effector functions on its own.

A

False

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23
Q

TCRαβ is a membrane protein with 3 domains. What are they?

A

Variable region
Constant region
Hinge region

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24
Q

What are CDRs and where are they found?

A

Hypervariable regions found within variable regions

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25
Q

Which CDR is most diverse?

A

CDR3

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26
Q

β-chain variable domain contains ________

A

CDR4- a 4th hypervariable region

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27
Q

CDR4 is the binding site for _________________

A

superantigens

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28
Q

T cells respond to ____ epitope

A

1

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29
Q

What are RAG-1 and RAG-2?

A

Recombination activating genes

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30
Q

RAGs are only found where?

A

In T and B lymphocytes

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31
Q

RAGs are only active in _______ lymphocytes.

A

developing

32
Q

T or F. Rearrangements can happen in both developing and mature T and B cells.

A

F. Only occur in developing T and B cells

33
Q

What happens if an animal lacks RAG proteins?

A

Failure to produce BCR and TCR proteins leading to SCID

34
Q

What is SCID?

A

Severe combined immunodeficiency

35
Q

Which chain genes rearrange first? Alpha or Beta?

A

β chain genes rearrange 1st

36
Q

What regions are at the TCRβ locus?

A

a. Vn (variable region genes)
b. Dn (diversity region genes)
c. Jn (joining region genes)

37
Q

What regions are at the TCRα locus?

A

a. Vn
b. Jn
c. NO diversity region genes

38
Q

Which region contributes to making CDR3?

A

Junction diversity contributes to making CDR3

39
Q

Diversity of TCRαβ is due to what 3 things?

A

i. Multiple germ line genes
ii. Gene rearrangements
iii. Junctional diversity

40
Q

What are the 3 components of Junctional diversity?

A

Base deletions
P-nucleotides
N-region nucleotide addition

41
Q

What is TdT and what is it responsible for?

A

TdT- Terminal deoxynucleotidyl transferase

Responsible for N-region nucleotide addition

42
Q

The total TCR repertoire is equal to _______

A

1 x 10^16

43
Q

What are the 2 signal transducers of T-cells?

A

CD3 Complex and ζζ (Zeta) Proteins

44
Q

What are accessory molecules that noncovalently bind to the T cell receptor?

A

CD3 Complex and ζζ (Zeta) Proteins

45
Q

What does the CD3 Complex consist of?

A

a. 4 invariant polypeptide chains
i. 2 ε
ii. 1 γ
iii. 1 δ

46
Q

What does the CD3 Complex do?

A

Stabilizes cell surface expression of TCR

47
Q

Because the cytoplasmic tail of the TCR is too small to transduce signals to the T cell nucleus, telling that it has bound an antigen, the signals come from what instead?

A

CD3 Complex and ζζ (Zeta) Proteins

48
Q

What do the two critical selection processes during T cell development result in?

A

i. Self-MHC restriction of TCRs

ii. Elimination of thymocytes whose TCRs bind to self-peptides

49
Q

What are the critical selection processes carried out by?

A

Thymic stromal cells- macrophages and dendritic cells

50
Q

What are the T cell subsets?

A

Helper T Cell

Cytotoxic T Cell

51
Q

Describe the Helper T Cell subset

A

a. TH and CD4+
b. Helps B cells produce antibodies to protein antigens
c. TH : Tc ratio is 2:1

52
Q

Describe the Cytotoxic T Cell subset

A

a. Tc and CD8+

b. Causes lysis of antigen bearing target cells

53
Q

Helper T Cells (CD4+T cells) only respond to antigen presented by MHC Class ______ molecules?

A

Class 2

54
Q

Naïve Helper T Cells require _______ signal(s) to become activated.

A

2 signals

55
Q

The following describes which signal? TCR complex and CD4 recognition of peptide-MHC complexes on the APC

A

Signal 1

56
Q

Costimulation is a characteristic of which signal?

A

Signal 2

57
Q

Of the Pro APC’s. the most potent activator of Naïve Helper T cells is _________

A

dendritic cells

58
Q

Why are dendritic cells the most potent activator of Naive Helper T cells?

A

Because they constitutively express MHC molecules and costimulators

59
Q

What are the co-stimulators for Naïve TH cells

A

B7 Proteins:
B7-1 (CD80)
B7-2 (CD86)

60
Q

Enhanced expression of B7 occurs when APC’s are stimulated by

A

Endotoxin LPS, interferon-γ, and the binding of CD40L to CD40 on the APC

61
Q

What is the T cell receptor for B7 proteins?

A

CD28

62
Q

Naive T cells differentiate into what two types?

A

Effector cells

Memory cells

63
Q

Which cytokine is the major co-stimulator of TH2 cells?

A

IL-1

64
Q

Which cytokine promotes IL-2?

A

IL-6

65
Q

What is the role of CD40 in T cell activation?

A

i. It’s the costimulation signal FOR the costimulation signal!
ii. Antigen recognition by helper T cell = expression of CD40L
iii. CD40L binds to CD40 on APC which stimulates expression of B7 molecules and stimulates secretion of cytokines that activate helper T cells
1. B7 binds to CD28 on the helper T cell

66
Q

What happens if IL-2 binds to IL-2R?

A

Clonal expansion

67
Q

Effector TH cells require _____ signal(s) to become activated.

A

1 signal

68
Q

What kind of cell can respond to peptide-MHC complexes on APC’s lacking B7?

A

Effector T helper cells

69
Q

Which cells are long lived? Naive T cells or Effector T cells?

A

Naive

70
Q

Which cells go to site of inflammation? Naive T cells or Effector T cells?

A

Effector

71
Q

Which cells bind more effectively? Naive T cells or Effector T cells?

A

Effector

72
Q

What kind of cell is “functionally quiescent” until re-exposure to an antigen?

A

Memory Helper T cells

73
Q

Memory Helper T cells are ______ lived cells

A

Long lived

74
Q

What happens when a memory helper T cell is re-exposed to an antigen?

A

Clonal expansion is induced then
daughter cell differentiation into
1. Effector cells
2. Memory cells

75
Q

Do memory helper T cells need signal 2 for activation?

A

No, only needs signal 1