T Helper Cell Differentiation
Polarization of naive CD4+ T cells into specialized effector subsets.
Overview
Naive CD4+ T cells differentiate into distinct subsets based on the cytokine environment: Th1 (IL-12, IFN-γ → T-bet → cell-mediated immunity), Th2 (IL-4 → GATA3 → humoral/allergic immunity), Th17 (IL-6, TGF-β → RORγt → mucosal defense), Treg (TGF-β, IL-2 → Foxp3 → immune suppression), and Tfh (IL-6, IL-21 → Bcl-6 → B cell help). Each subset produces characteristic cytokines and mediates distinct immune functions.
Cellular Location
Lymph nodes, tissues
Clinical Significance
Th1/Th2 imbalance underlies allergies and autoimmunity; Th17 in psoriasis and IBD (anti-IL-17 therapy); Tregs critical for tolerance; checkpoint immunotherapy modulates these.
Key Molecules
Key Enzymes
Related Pathways
T Cell Receptor Signaling
Antigen-specific activation of T lymphocytes via TCR-MHC interaction.
JAK-STAT Pathway
Cytokine-driven signaling from receptor to gene expression via STAT dimerization.
TGF-β/BMP Signaling
Multifunctional cytokine signaling controlling growth, differentiation, and immune regulation.