T helper 2-mediated immune response pathway (Th2 pathway)

The T helper 2-mediated immune response pathway, often referred to as the Th2 pathway or type 2 inflammation, is a specialized arm of the adaptive immune system primarily responsible for defense against extracellular parasites, such as helminths, and the regulation of humoral immunity [NIH, 2021; Nature Reviews Immunology, 2010]. This pathway is initiated when naive CD4+ T cells differentiate into Th2 cells under the influence of interleukin-4 (IL-4) and the master transcription factor GATA3 [Frontiers in Immunology, 2023]. Activated Th2 cells secrete a characteristic set of cytokines, including IL-4, IL-5, and IL-13, which coordinate various effector functions such as B cell class switching to IgE, eosinophil recruitment, and mucus hypersecretion by goblet cells [PubMed, 2021]. While essential for host protection, chronic or excessive activation of the Th2 pathway is a central driver in the pathogenesis of allergic and atopic diseases, including asthma, atopic dermatitis, and chronic rhinosinusitis [MDPI, 2025]. Consequently, this pathway has become a major focus for therapeutic intervention, with several monoclonal antibodies developed to target specific cytokines or their receptors to mitigate type 2 inflammation [NIH, 2021]. These targeted therapies have significantly improved outcomes for patients with severe Th2-driven conditions by interrupting the inflammatory cascade at multiple levels [MDPI, 2025].

Other names

Type 2 immune responseTh2 immunityT helper 2 pathwayTh2 axisType 2 inflammation

Therapeutic agents modulate the Th2 pathway by inhibiting key cytokines (IL-4, IL-5, IL-13, IL-31), their respective receptors (IL-4Rα, IL-5Rα, IL-31R), or upstream alarmins (TSLP) to suppress the type 2 inflammatory cascade [NIH, 2021; MDPI, 2025].