L14- CD4+ T helper cells Flashcards
What are effector functions of CD4+ T helper cells?
Proliferation
Cytokines
B cell help
APC activation
How does T cell activation occur?
Signal 1- Recognition of MHCII molecule on APC/Bcell by the TCR provides a signal which initiates activation of T cells.
Signal 2- Interaction of co-stimulatory molecules on surface of B and T cells.
What types of T cells do naieve CD4+ T cells differentiate into?
Th1- Coordinate inflammatory immune responses to intracellular pathogens (bacteria, viruses)
Th2- Help B cells make antibodies required for immune responses to extracellular pathogens
Both promote the generation of more leukocytes
What cytokines do Th1 cells produce?
IL2
IFN gamma
TNF beta
GMCSF
IL3
What cytokines do Th2 cells produce?
IL4
IL5
IL13
GMCSF
IL3
What does IL2 do?
Proliferation of activated T cells, enhancement of NK and T cell activity
What does IFN gamma do?
Macrophage activation
Elevation of MHCI and MHCII expression
Enhances NK and CD8+ activity
Class switching to IgG2a
What does TNF alpha/beta do?
Macrophage activation
Killing of transformed cells
What does IL4 do?
B cell proliferation
Class switching to IgE
Suppresses Th0 to Th1 differentiation
What does IL5 do?
B cell proliferation
Class switching to IgA
What does IL13 do?
B cell proliferation
Class switching to IgE
What does IL3 do?
Haematopoiesis
What does GM-CSF do?
Haematopoiesis
Differentiation of monocytes to macrophages
What are the transcription factors controlling Th1 differentiation?
IFN gamma
IL12
——> Stat1+4 and T-bet
What are the transcription factors controlling Th2 differentiation?
IL4
——-> gata3, cMaf (master regulator), Stat6