Chapter 5: Activation of T cells

Question 1

What type of microbes are phagocytosed?

Answer 1

• intracellular bacteria
• fungi
• protozoa

Question 2

What type of microbes infect nonphagocytic cells?

Answer 2

• viruses
• rickettsiae
• protozoa

Question 3

Effector T cells encounter antigens and what action occurs?

Answer 3

• leukocyte activation (inflammation)
• phagocytosis and killing of microbes
• CTL killing of infected cell

Question 4

What are the steps in activation of T lymphocytes?

Answer 4

• antigen recognition
• cytokine secretion
• proliferation
• differentiation
• effector functions

Question 5

What are the effector functions of T cells?

Answer 5

CD4+ = activation of macrophages, B cells, other cells
CD8+ = killing of infected “target cells”; macrophage activation

Question 6

After differentiation of T lymphocytes do they become effector T cells or memory T cells?

Answer 6

both

Question 7

Signal transduction for Class II MHC is via CD4 or CD8?

Answer 7

CD4

Question 8

Signal transduction for Class I MHC is via CD4 or CD8?

Answer 8

CD8

Question 9

What ligand allows for T cell adhesion?

Answer 9

LFA-1

Question 10

LFA-1 is an ______ protein

Answer 10

integrin
- for adhesion

Question 11

ICAM-1 is a _______

Answer 11

ligand for adhesion

Question 12

What is the costimulation from the antigen presenting cell to the T cell to activate it?

Answer 12

B7

Question 13

What happens if MHC binds from cell to T cell but there is no costimulator?

Answer 13

no response

Question 14

When MHC binds and the antigen presenting cell is activated what is secreted?

Answer 14

B7 costimulator
cytokines (IL-12 or 2)

Question 15

_________ receptors are necessary for limiting/terminating immune responses

Answer 15

Inhibitory

Question 16

What ligand/receptor combo is necessary for activation of T cell?

Answer 16

B7
CD28

Question 17

APCs that engulf virus infected cells and also are infected themselves will have antigens presented by…

Answer 17

both class I and II MHC molecules

Question 18

What ligand allows for proliferation of T cells?

Answer 18

IL-2R

Question 19

Signal transduction pathways in T lymphocytes involve a lot of…

Answer 19

phosphorylation and dephosphorylation

Question 20

What is the space between the APC and T cell called?

Answer 20

immunological synapse

Question 21

What do the drugs cyclosporine and rapamycin do?

Answer 21

interfere with the signal transduction pathways in T cells
- used in transplant patients to prevent rejection

Question 22

What is the principle function of IL-2?

Answer 22

survival and proliferation of antigen-specific T cells

Question 23

What is the antigen and costimulator required for T cell activation?

Answer 23

CD28
B7

Question 24

What is the affinity difference between a T cell with IL-2RByc and IL-2RaByc?

Answer 24

low affinity - IL-2RByc
high affinity - IL-2RaByc

Question 25

What causes the difference between IL-2RByc and IL-2RaByc on the T cell?

Answer 25

IL-2 secretion

Question 26

T follicular helper cells remain where?

Answer 26

in lymphoid organ and migrate to the follicles

Question 27

Effector T cells and antibodies enter circulation and go to…

Answer 27

sites of infection

Question 28

CD4+ T cells activate…

Answer 28

macrophages - killing of phagocytosed microbes
B cells - secretion of antibodies

Question 29

How do CD4+ T cells activate macrophages and B cells?

Answer 29

CD40L and cytokines

Question 30

S1P is required for naive T cells or Activated T cells?

Answer 30

both

Question 31

What T cell homing receptors are required for naive and effector T lymphocytes?

Answer 31

selectin
integrin
chemokine receptor

Question 32

What are the T cell homing receptors for naive T cells?

Answer 32

L-selectin
LFA-1
CCR7