Chapter 8: T Cell-Mediated Immunity

Front 1

What do naive T cells migrate through and what do they sample?

Back 1

Naive T cells migrate through the peripheral lymphoid tissues and sample peptide:MHC complexes on dendritic cells.

Front 2

What is lymphocyte entry into lymphoid tissues dependent on?

Back 2

Lymphocyte entry into lymphoid tissues depends on chemokines and adhesion molecules.

Front 3

What is responsible for the entry of naive T cells into lymph nodes?

Back 3

Activation of integrins by chemokines is responsible for the entry of naive T cells into lymph nodes.

Front 4

T cells coming from the blood enter the lymph node cortex via what?

Back 4

T cells enter the lymph node cortex from the blood via HIGH ENDOTHELIAL VENULES (HEVs).

Front 5

T cells that aren't activated by Ag presented by dendritic cells exit the lymph node via what?

Back 5

T cells not activated by Ag presented by dendritic cells exit the lymph node via the CORTICAL SINUSES.

Front 6

What do T cells activated by Ag presented by dendritic cells do and what ability do they lose?

Back 6

T cells activated by Ag presented by dendritic cells START TO PROLIFERATE AND LOSE THE ABILITY TO EXIT THE LYMPH NODE.

Front 7

What do activated T cells differentiate to?

Back 7

Activated T cells differentiate to EFFECTOR CELLS AND EXIT THE LYMPH NODE.

Front 8

What do naive T cells encounter in the paracortical areas of the lymph node?

Back 8

T cells encounter mature dendritic cells in the paracortical areas of the lymph node.

Front 9

Briefly describe the steps of lymphocyte entrance into a lymph node.

Back 9

[Rolling, activation, adhesion, diapedesis]
1. Naive T cell rolls along HEV due to interactions between selectins (T cell) and vascular addressins (endothelial cell membranes)
2. Chemokines at HEV surface activate receptors on T cell
3. Chemokine signaling induces increased affinity of T cell integrins for LFA-1 on HEV (strong adhesion)
4. After adhesion, T cells follow chemokine gradients, passing through HEV into paracortical region of LN

Front 10

Following activation of T cells in the LN by Ag-presenting dendritic cells, how long does it take for effector T cells to leave, and where do they exit?

Back 10

By 5 days after the arrival of Ag, activated effector T cells are leaving the LN in large numbers via the efferent lymphatics.

Front 11

What is the main function of CD8 cytotoxic T cells in the adaptive immune response?

Back 11

Kill virus-infected cells

Front 12

What is the main function of CD4 Th1 cells in the adaptive immune response?

Back 12

Activate infected macrophages and provide help to B cells for Ab production

Front 13

What is the main function of CD4 Th2 cells in the adaptive immune response?

Back 13

Provide help to B cells for Ab production, especially switching to IgE

Front 14

What is the main function of CD4 Th17 cells in the adaptive immune response?

Back 14

Enhance neutrophil response

Front 15

What is the main function of CD4 regulatory T cells in the adaptive immune response?

Back 15

Suppress T cell responses

Front 16

What pathogens are targeted by CD8 cytotoxic T cells?

Back 16

Viruses (influenza, rabies, vaccinia) and some intracellular bacteria

Front 17

What pathogens are targeted by CD4 Th1 cells?

Back 17

Microbes that persist in macrophage vesicles (mycobacteria, Listeria, Leishmania donovani, Pneumocystis carinii) and some extracellular bacteria

Front 18

What pathogens are targeted by CD4 Th2 cells?

Back 18

Helminth parasites

Front 19

What pathogens are targeted by CD4 Th17 cells?

Back 19

Extracellular bacteria (Salmonella enterica)

Front 20

What is the location of dendritic cells?

Back 20

Ubiquitous throughout the body

Front 21

What is the location of macrophages?

Back 21

Lymphoid tissue, connective tissue, and body cavities

Front 22

What is the location of B cells?

Back 22

Lymphoid tissue and peripheral blood

Front 23

What Ag is presented by dendritic cells?

Back 23

Peptides, viral Ags, allergens

Front 24

What Ag is presented by macrophages?

Back 24

Particulate Ags, intracellular and extracellular pathogens

Front 25

What Ag is presented by B cells?

Back 25

Soluble Ags, toxins, and viruses

Front 26

Rate the MHC expression on dendritic cells.

Back 26

Low on tissue dendritic cells and high on dendritic cells in lymphoid tissue

Front 27

Rate the MHC expression on macrophages.

Back 27

Inducible by bacteria and cytokines (- to +++)

Front 28

Rate the MHC expression on B cells.

Back 28

Constitutive, Increases on activation (+++ to ++++)

Front 29

Antigen uptake by dendritic cells...

Back 29

(+++) Macropinocytosis and phagocytosis by tissue dendritic cells; viral infection

Front 30

Antigen uptake by macrophages...

Back 30

(+++) Phagocytosis

Front 31

Antigen uptake by B cells...

Back 31

(++++) Ag-specific receptor (Ig)

Front 32

Co-stimulator delivery for dendritic cells...

Back 32

constitutive by mature, nonphagocytic lymphoid dendritic cells (++++)

Front 33

Co-stimulator delivery for macrophages...

Back 33

inducible (- to +++)

Front 34

Co-stimulator delivery for B cells...

Back 34

inducible (- to +++)

Front 35

High-affinity IL-2 receptors are...

Back 35

High-affinity IL-2 receptors are THREE-CHAIN STRUCTURES THAT ARE PRESENT ONLY ON ACTIVATED T CELLS.

Front 36

How many kinds of signals do APCs deliver to naive T cells?

Back 36

three

Front 37

What parts of the IL-2 receptor are present on resting T cells?

Back 37

beta and gamma chains (expressed constitutively) - they bind IL-2 w/ moderate affinity

Front 38

Activation of T cells induces the synthesis of the alpha chain and the...

Back 38

formation of the high-affinity heterotrimeric receptor.

Front 39

What cells are by far the strongest activators of naive T cells

Back 39

mature dendritic cells

Front 40

Mature conventional dendritic cells are primarily concerned with what?

Back 40

activation of naive T cells