T Cell Effector Mechanisms

Question 1

2 primary ways effector T cells differ form naive T cells

Answer 1

1. Do not require B7 to become activated

2. Express different surface adhesion molecules that direct them to tissues and inflammatory sites

Question 2

L-selectin located on ____

Answer 2

naive CD4 and CD8 cells and effector CD4 cells but NOT CD8 cells

Question 3

LFA-a located on _____

Answer 3

naive and effector T cells, higher concentration on effector

Question 4

VLA-4 located on ____

Answer 4

effector T cells only, binds VCAM-1 to allow effector T cells to enter inflammatory tissue

Question 5

CD45Ra located on ____

Answer 5

naive T cells only

Question 6

CD45Ro located on ____

Answer 6

effector and memory T cells

Question 7

CD8 Effector T cells (CTLs)

Answer 7

initiate programmed cell death

Question 8

3 effector molecules of CTLs

Answer 8

perforin-forms pores in the cytoplasmic membrane of the host cell
granulysin-forms pores, has antimicrobial function
granzymes- initiate the apoptotic pathway in host cells via capsize cascade
All released when CTL degranulates

Question 9

Fas ligand, additional effector molecule of CTLs

Answer 9

FAS ligand-binds 3 copies of Fas on host cell, adaptor proteins activate capsize 8 and 3, once 3 is activated it cleaves iCAD and activates the DNAse leading to cell death
Released when CTL degranulates

Question 10

T/F one CTL can kill many infected host cells?

Answer 10

true

Question 11

IFN-gamma

Answer 11

as an effector molecule of CTL’s it’s important function is to drive differentiation of Th0»>Th1

Question 12

How do CTL’s prevent killing cells other than infected host cells when they degranulate?

Answer 12

Polarization

Question 13

2 most important effector functions of Th1

Answer 13

1. supply secondary activation to B cells

2. activate macrophages

Question 14

macrophage activation by Th1

Answer 14

CD-40 ligand on the T cell binds CD-40 on the macrophage and T cell produces IFN-gamma which activates the macrophage-makes it more phagocytic, a better APC, and more bactericidal

Question 15

activated macrophages produce

Answer 15

1. NO and ROS-makes them more bactericidal

2. More MHC class I/II and B7-making it a better APC

Question 16

B cell activation by Th1

Answer 16

promotes class switching to strongly opsonizing Igs-IGG1 and IgG3

Question 17

granulomas

Answer 17

prevent pathogen dissemination

composed primarily of macrophages (fuse to form giant multinuclear cell) with Th1 effector cells around periphery

Question 18

Patients who lack CD40 or CD40 ligand cannot produce____

Answer 18

granulomas, Th1 cells are required for this formation

Question 19

Th17 cytokines

Answer 19

IL-17 (neutrophil chemotractant) IL-22 (antimicrobial function)

Question 20

Tregs recquire B7 costimulation T/F

Answer 20

true (uses CTLA-4 and B7)

Question 21

IL-2

Answer 21

produced by Th1, CTLs and naive T cells

induces proliferation of activated T cells

Question 22

IFN-gamma

Answer 22

produced by Th1 and CTLs

macrophage activation

Question 23

TNF-beta

Answer 23

produced by Th1 and CTLs

macrophage activation

Question 24

IL-4

Answer 24

produced by Th2
promotes class switching to IgE

Question 25

IL-5

Answer 25

``` produced by Th2 promotes class switching to IgA ```

Question 26

IL-10

Answer 26

produced by Th2 and Tregs anti-inflammatory effects that result in an inhibition of cytokine release by macrophages inhibition of T cell activation

Question 27

IL-3

Answer 27

produced by Th1/2 and CTLs | serves as a growth factor for hematopoietic progenitor cells in the bone marrow

Question 28

TNF-alpha

Answer 28

produced by Th1/2 and CTLs serves as an activation signal for macrophages and as a activator of vascular endothelium allowing the macrophages to get where they need to go essentially

Question 29

GMCSF

Answer 29

produced by Th1/2 and CTLs serves as a growth factor for hematopoietic progenitor cells in the bone marrow resulting in increased production of macrophages and granulocytes.

Question 30

TGF-beta

Answer 30

anti-inflammatory cytokine produced by Tregs | inhibits T cell activation

Question 31

IL-17

Answer 31

produced by Th17 | signal for induction of neutrophil chemokines by endothelial cells

Question 32

IL-22

Answer 32

produced by Th17 | serves as a signal for induction of antimicrobial peptide production by endothelial cells

Question 33

Fas Ligand on Th1 cells

Answer 33

allows them to deactivate/kill worn out macrophages

Question 34

CD40 ligand

Answer 34

Th1 produces CD40 ligand which binds CD40 receptor on macrophages Effector T cells also activate B cells through CD40 mechanism

Question 35

T/F Patients without CD40 ligand cannot activate macrophages to form granulomas?

Answer 35

true

Question 36

cytokine receptors are

Answer 36

JAK/STAT tyrosine kinases