has part lacks_plasma_membrane_part capable of CD4-positive helper T cell T-helper 2 cell Th2 T-lymphocyte Th2 T cell FMA:84385 Th2 T-cell BTO:0001679 https://cellxgene.cziscience.com/cellguide/CL_0000546 T(H)-2 cell T-helper 2 cells (Th2 cells) are a subset of CD4+ T lymphocytes, which play central roles in cell-mediated immunity. All T lymphocytes are uniquely characterized by the expression of a T-cell receptor (TCR) complex on their cell surface. Th2 cells express the CD4 co-receptor which enables the T-cell receptor to engage with antigen-presenting cells and perform their influential role in adaptive immune response. Th2 cells differentiate from naïve CD4+ T cells following TCR ligation and specific cytokine signaling. Th2 cell development and stabilization requires the master regulatory transcription factor GATA-3. Furthermore, IL-4-mediated activation of STAT6 is thought to play an important role in Th2 cell differentiation. The primary function of Th2 cells is to coordinate the immune response against extracellular pathogens, particularly parasitic helminths. They achieve this primarily through the secretion of their signature cytokines – the interleukins IL-4, IL-5, and IL-13. For instance, IL-4 promotes the differentiation of B cells into plasma cells that produce immunoglobulin E (IgE), a class of antibodies that mediate the immune response to parasites and are involved in allergic reactions. IL-5 promotes the activation and survival of eosinophils, a type of white blood cell that is effective against certain parasites. IL-13 works alongside IL-4 but also influences mucus production in the respiratory tract, an important defense mechanism against parasites. Despite their critical roles in host defense, an overactive Th2 response can also lead to pathological outcomes such as allergy and asthma. These health issues are typically characterized by excessive IgE production, eosinophilic inflammation, and mucus hypersecretion, all hallmarks of a Th2 response. In these instances, the immune system reacts excessively to normally harmless substances like pollen, dust mites, or certain foods, with the Th2 cells driving this overreaction. As such, understanding the precise pathways and mechanisms through which Th2 cells operate not only provides insight into protective immune responses but also potential therapeutic targets for treating allergies and other related conditions. (This extended description was generated by ChatGPT and reviewed by the CellGuide team, who added references, and by the CL editors, who approved it for inclusion in CL. It may contain information that applies only to some subtypes and species, and so should not be considered definitional.) A CD4-positive, alpha-beta T cell that has the phenotype GATA-3-positive, CXCR3-negative, CCR6-negative, and is capable of producing interleukin-4. This cell type is compatible with the HIPC Lyoplate markers for 'non-Th1/Th17 CD4+ T cell' (see CL:0001051), but includes the additional necessary and sufficient conditions to allow classification as a T-helper 2 T cell. MESH:D018418 T helper cells type 2 Th2 T lymphocyte helper T cell type 2 Th2 cell CD4-positive, CXCR3-negative, CCR6-negative, alpha-beta T cell interleukin-4 production Homo sapiens C-C chemokine receptor type 6 C-X-C chemokine receptor type 3 trans-acting T-cell-specific transcription factor GATA-3