T Cell Mediated Immunity Flashcards

1
Q

T cells that encounter antigen proliferate into ____ cells

A

Effector

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2
Q

CD4+ T cells recognize ________

A

HLA Class II

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3
Q

CD8+ T cells recognize _________

A

HLA Class I

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4
Q

TCR/HLA antigen recognition changes ____ conformation on T cells from low to high affinity

A

Integrins

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5
Q

During co-stimulation, what cell constituvely expresses CD40 and CD28?

A

APCs constitutively express CD40

T cells constitutively express CD28

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6
Q

During co-stimulation, what cells increase CD40L and CD80? Note which cell/receptor these bind to.

A

CD40L is increased on T cells
CD80 (B7) is increased on APCs

CD40L (T cells) binds to CD40 (APCs)
CD80 (APCs) binds to CD28 (T cells)

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7
Q

What is the signaling chain on T cells? How does it make an intracellular signal.

A

Zeta

ITAMS- Immunoreceptor Tyrosine Based Action Motifs

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8
Q

Describe a situation of Anergy (unresponsiveness) during T cell response.

A

T cells recognize antigen without binding of co-stimulatory ligands or cytokine support will not become activated

Anergy= Anergic/Tolerant

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9
Q

What is the function of IL-2 in terms of T cell function? What cell releases IL-2?

A

T cell proliferation and T cell survival

Activated T cells release IL-2

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10
Q

What is the function of IFN-gamma? What cells release this?

A

Activation of Macrophages

CD4+ and CD8+ T cells and NK cells

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11
Q

What is the function of IL4? What cells release this?

A

B cells switching to IgE

Mast cells
CD4+ T cells

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12
Q

What is the function of IL5?

A

Activation of eosinophils

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13
Q

What is the function of IL17?

A

Stimulation of acute inflammation

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14
Q

What are the functions of TGF-beta and IL10?

A

Inhibition of T cell activation

Differentiation of regulatory T cells

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15
Q

How are T cells trapped into lymph nodes?

A

CD69 expression leads to the sequestering of the S1PR1 receptor and therefore traps the T cell in the lymph node

S1PR1=Sphingosine 1 Phosphate Receptor 1

*Note that 5 days after the arrival of the antigen, S1PR1 is re-expressed and therefore allows the T cell to emigrate from the lymph node

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16
Q

What cell releases IFN-gamma and IL12 and what are the functions of these cytokines?

A

Th1 releases these cytokines

Leads to the activation of Macrophages

17
Q

What cell releases IL4/IL5/IL13 and what are the functions of these cells?

A

Th2 releases these cytokines

Leads to the activation of Eosinophils
B cell class switching to IgE
18
Q

What cell releases IL-17 and IL-22? What is the function of these cytokines?

A

Th17

Neutrophil recruitment and activation

19
Q

What cell releases IL21? What is the function of this cytokine?

A

Thf cells release these cytokines

Leads to antibody production on B cells

20
Q

What receptors do Treg cells constitutively express?

A

CTLA4 and CD25

21
Q

what transcription factor do Treg cells release?

A

FOXp3

22
Q

What is the major difference between effector T cells and resting naive T cells?

A

An effector T cell is able to respond to a specific antigen without the need for co-stimulation via B7 (CD80)-CD28 interaction

23
Q

What transcription factor do Th1 cells release?

A

Tbet

24
Q

During Classical Activation of Macrophages, what cytokine activates macrophages against intracellular microbes?

A

IFN-gamma, which activates B cells to stimulate class switching and complement binding. Th1 releases IFN-gamma

This stimulates class II HLA and B7 (CD80) expression

25
Q

What transcription factor does Th2 release?

A

GATA3

26
Q

During Alternative Activation of Macrophages, what cytokine activates macrophages for tissue repair?

A

IL4 and IL13 from Th2

27
Q

What transcription factor does Th17 release?

A

RORyt

28
Q

What are the 2 killing mechanisms of Cytotoxic T Lymphocyte Function?

A

Cytotoxins are delivered directly onto the surface of the infected target cell.
Granular proteins:
-Granzymes- activates caspases
-Perforin- necessary for delivery of granzymes

Fas(CD95) and FasL: simulates of apoptotic pathways

29
Q

What are the 5 cells that are involved in Antibody Dependent Cell Mediated Cytotoxicity (ADCC)? What 2 antibodies are used in this?

A
NK cells
Macrophages
Monocytes
Neutrophils
Eosinophils

Target recognition through IgG or IgE

30
Q

What cell constitutively expresses CD28? What is the function of CD28?

A

T cells constitutively express CD28

Involved in co-stimulation of naive T cells
Development of Treg cells

31
Q

What cell expresses CTLA-4? What is the function of CTLA-4?

A

T cells increase expression of CTLA-4

Negative regulation of immune responses
Self-tolerance

32
Q

What cell expresses ICOS? What are the 2 functions of ICOS?

A

T cells increase expression of ICOS

Co-stimulation of effector and regulatory T cells
Generation of Follicular Helper T cells

33
Q

What cell expresses PD-1? What is the function of PD-1 on T cells?

A

T cells
B cells

Negative regulation of T cells- leads to T cell exhaustion causing no cytokine secretion and reduced proliferation.

34
Q

What is the mechanism of Mycobacterium?

A

Inhibition of the formation of the phagolysosome

35
Q

What is the mechanism of the Herpes Simplex Virus (HSV)?

A

Inhibition of antigen presentation by the HSV peptide interfering with the TAP transporter

36
Q

What is the mechanism of the cytomegalovirus (CMV)?

A

Inhibition of antigen presentation by inhibiting the removal of class I MHC molecules from the ER.

37
Q

What are the 2 mechanisms of the Epstein Barr virus (EBV)?

A

Inhibition of antigen presentation: Inhibition of proteasomal activity from degrading the viral antigens

Production of IL10, which leads to the inhibition of macrophage and dendritic cell activation

38
Q

What is the mechanism of the pox virus?

A

Inhibiting the activation of effector cells by blocking soluble cytokines from being released.

Soluble Cytokines- IL1 and IFN-y

39
Q

What 2 cytokine signals do Memory T cells require in order to survive?

A

IL7 and IL15