Th2 cytokine signaling and Th1 cytokine Interferon-gamma (IFN-gamma) (Th1/Th2 axis)

Th2 cytokine signaling and Th1 cytokine Interferon-gamma (IFN-gamma) represent the two primary axes of the adaptive immune system's helper T-cell response. Th2 signaling is driven by cytokines such as IL-4, IL-5, and IL-13, which are critical for mediating allergic inflammation and defense against helminthic parasites [1]. Conversely, IFN-gamma is the signature cytokine of the Th1 response, essential for activating macrophages and coordinating the immune response against intracellular pathogens and tumors [2]. The balance between these two pathways is vital for immune homeostasis; an imbalance toward Th2 is associated with atopic diseases like asthma and atopic dermatitis, while a Th1-skewed response is often linked to organ-specific autoimmune diseases [3]. Therapeutic intervention in these pathways involves the use of monoclonal antibodies to neutralize specific cytokines or block their receptors, such as Dupilumab (targeting IL-4Ralpha) for Th2-mediated conditions and Emapalumab (targeting IFN-gamma) for primary hemophagocytic lymphohistiocytosis [4, 5]. Additionally, small molecule inhibitors of the Janus kinase (JAK) family are frequently employed to disrupt the downstream signaling cascades (JAK/STAT) initiated by these cytokines [6].

Other names

Th1/Th2 balanceTh1/Th2 cytokine axisT-helper cell differentiation pathwayType 1 and Type 2 immune responses

Therapeutic agents modulate this axis by neutralizing specific cytokines (e.g., IL-4, IL-5, IL-13, or IFN-gamma), blocking their respective cell-surface receptors (e.g., IL-4Ralpha, IL-5Ralpha), or inhibiting the intracellular Janus kinase (JAK) enzymes that mediate downstream signal transduction [4, 5, 6].