Helper T Cells Flashcards
What is GATA-3?
A transcription factor that control Th2 differentiation in CD4 T cells
What does GATA-3 do?
- Activates Th2 cytokines
- Inhibits Th1 differentiation by suppressing T-bet
What are the Th2 cytokines?
IL-4, IL-5, IL-13
What triggers GATA-3 actiavtion?
IL-4 mainly from mast cells, basophils and eosinophils
What happens if GATA-3 is overactive?
Leads to allergic disease
What happens if GATA-3 is deficient?
Weakened Th2 response
What is IL-12?
A cytokine that promotes Th1 differentiation
What cells produce IL-12?
Dendrite cells and macrophages in response to intracellular pathogens
What does IL-12 do?
- Activates STAT4 increasing IFN-gamma production
- Strengthens Th1 response
- Enhances CD8 T cell and NK cell activity
What happens if IL-12 is overactive?
Leads to autoimmune disease due to excessive Th1 activation
What happens if IL-12 is deficient?
Weak Th1 response increasing the risk of intracellular infections
What are the two major Th cell subsets?
Th1 cells
Th2 cells
What do Th1 cells do?
- Activate macrophages
- Increase phagocytosis
- Upregulate MHC expression
- Induce nitric oxide production
What do Th2 cells do?
- Activate B cells increasing antibody production
- Enhance eosinophil and mast cell responses to kill helminths
- Stimulate mucus secretion
- Contribute to allergic diseases
What is the key cytokine and master regulator of Th1 cells?
Cytokine: Interferon gamma
Regulator: T-bet
