Th2type

Th2-type refers to a subset of CD4+ T helper cells that coordinate humoral and allergic immune responses. This polarization is characterized by the production of cytokines such as interleukin-4 (IL-4), IL-5, IL-9, and IL-13, and by the transcription factor GATA3. Th2-type responses are typically elicited when antigen-presenting cells encounter proteins in a cytokine milieu rich in IL-4 and IL-2, promoting differentiation of naive CD4+ T cells into Th2 cells.

Functions of Th2-type responses include helping B cells undergo class switching to immunoglobulin E (IgE), promoting eosinophil activation and recruitment, and stimulating mucus production and airway hyperreactivity via IL-13. Th2 cytokines also drive alternative macrophage activation, contributing to tissue remodeling and defense against extracellular parasites such as helminths. In many contexts, Th2 responses enhance humoral immunity and antibody-mediated defense.

Regulation and plasticity are central to Th2 biology. Differentiation relies on IL-4 signaling through STAT6, with GATA3 as a central regulator of the Th2 program. IFN-γ and IL-12 antagonize Th2 differentiation, while regulatory T cells and IL-10 can dampen Th2 activity. Th2 cells can exhibit plasticity, shifting under certain inflammatory conditions or in response to the local cytokine environment.

Clinical relevance includes a central role for Th2-type responses in defense against helminths and in the pathogenesis of IgE-mediated allergic diseases such as asthma, allergic rhinitis, and atopic dermatitis. Excessive Th2 activity can lead to eosinophilic inflammation and mucus hypersecretion, contributing to tissue obstruction. Therapeutic strategies target Th2-associated pathways, including IL-4, IL-13, and IL-5 signaling, to alleviate allergic symptoms.

In research, Th2-type responses are assessed by cytokine profiles and GATA3 expression, intersecting with Th1 and Th17 immune pathways to shape overall immune balance.