T Cell Mediated Immunity

Question 1

T cells that encounter antigen proliferate into ____ cells

Answer 1

Effector

Question 2

CD4+ T cells recognize ________

Answer 2

HLA Class II

Question 3

CD8+ T cells recognize _________

Answer 3

HLA Class I

Question 4

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

Answer 4

Integrins

Question 5

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

Answer 5

APCs constitutively express CD40

T cells constitutively express CD28

Question 6

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

Answer 6

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)

Question 7

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

Answer 7

Zeta

ITAMS- Immunoreceptor Tyrosine Based Action Motifs

Question 8

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

Answer 8

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

Anergy= Anergic/Tolerant

Question 9

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

Answer 9

T cell proliferation and T cell survival

Activated T cells release IL-2

Question 10

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

Answer 10

Activation of Macrophages

CD4+ and CD8+ T cells and NK cells

Question 11

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

Answer 11

B cells switching to IgE

Mast cells
CD4+ T cells

Question 12

What is the function of IL5?

Answer 12

Activation of eosinophils

Question 13

What is the function of IL17?

Answer 13

Stimulation of acute inflammation

Question 14

What are the functions of TGF-beta and IL10?

Answer 14

Inhibition of T cell activation

Differentiation of regulatory T cells

Question 15

How are T cells trapped into lymph nodes?

Answer 15

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

Question 16

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

Answer 16

Th1 releases these cytokines

Leads to the activation of Macrophages

Question 17

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

Answer 17

Th2 releases these cytokines

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

Question 18

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

Answer 18

Th17

Neutrophil recruitment and activation

Question 19

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

Answer 19

Thf cells release these cytokines

Leads to antibody production on B cells

Question 20

What receptors do Treg cells constitutively express?

Answer 20

CTLA4 and CD25

Question 21

what transcription factor do Treg cells release?

Answer 21

FOXp3

Question 22

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

Answer 22

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

Question 23

What transcription factor do Th1 cells release?

Answer 23

Tbet

Question 24

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

Answer 24

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

Question 25

What transcription factor does Th2 release?

Answer 25

GATA3

Question 26

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

Answer 26

IL4 and IL13 from Th2

Question 27

What transcription factor does Th17 release?

Answer 27

RORyt

Question 28

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

Answer 28

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

Question 29

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

Answer 29

``` NK cells Macrophages Monocytes Neutrophils Eosinophils ``` Target recognition through IgG or IgE

Question 30

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

Answer 30

T cells constitutively express CD28 Involved in co-stimulation of naive T cells Development of Treg cells

Question 31

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

Answer 31

T cells increase expression of CTLA-4 Negative regulation of immune responses Self-tolerance

Question 32

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

Answer 32

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

Question 33

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

Answer 33

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

Question 34

What is the mechanism of Mycobacterium?

Answer 34

Inhibition of the formation of the phagolysosome

Question 35

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

Answer 35

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

Question 36

What is the mechanism of the cytomegalovirus (CMV)?

Answer 36

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

Question 37

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

Answer 37

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

Question 38

What is the mechanism of the pox virus?

Answer 38

Inhibiting the activation of effector cells by blocking soluble cytokines from being released. Soluble Cytokines- IL1 and IFN-y

Question 39

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

Answer 39

IL7 and IL15