T Cell Effector Mechanisms Flashcards
2 primary ways effector T cells differ form naive T cells
- Do not require B7 to become activated
2. Express different surface adhesion molecules that direct them to tissues and inflammatory sites
L-selectin located on ____
naive CD4 and CD8 cells and effector CD4 cells but NOT CD8 cells
LFA-a located on _____
naive and effector T cells, higher concentration on effector
VLA-4 located on ____
effector T cells only, binds VCAM-1 to allow effector T cells to enter inflammatory tissue
CD45Ra located on ____
naive T cells only
CD45Ro located on ____
effector and memory T cells
CD8 Effector T cells (CTLs)
initiate programmed cell death
3 effector molecules of CTLs
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
Fas ligand, additional effector molecule of CTLs
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
T/F one CTL can kill many infected host cells?
true
IFN-gamma
as an effector molecule of CTL’s it’s important function is to drive differentiation of Th0»>Th1
How do CTL’s prevent killing cells other than infected host cells when they degranulate?
Polarization
2 most important effector functions of Th1
- supply secondary activation to B cells
2. activate macrophages
macrophage activation by Th1
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
activated macrophages produce
- NO and ROS-makes them more bactericidal
2. More MHC class I/II and B7-making it a better APC
