T-cell helper type 17 response (Th17 response)

The T-cell helper type 17 (Th17) response is a specialized arm of the adaptive immune system characterized by the production of pro-inflammatory cytokines, including interleukin-17A (IL-17A), IL-17F, and IL-22 [PubMed: 28211020]. This response is primarily driven by the differentiation of CD4+ T cells under the influence of cytokines such as IL-6, TGF-beta, and IL-23, a process orchestrated by the master transcription factor ROR-gamma-t (RORγt) [StatPearls: NBK541082]. Biologically, the Th17 response is essential for host defense against extracellular bacteria and fungi and for maintaining the integrity of mucosal barriers [NIH: PMC4994090]. However, its dysregulation is a central driver of several chronic inflammatory and autoimmune conditions, most notably psoriasis and ankylosing spondylitis [PubMed: 27151918]. In drug development, the Th17 response is typically addressed as a therapeutic axis rather than a single molecular target. Current therapies target specific components of this pathway, such as monoclonal antibodies that neutralize IL-17A (e.g., secukinumab) or inhibit the p19 subunit of the upstream regulator IL-23 (e.g., risankizumab) [PubMed: 30272097]. While these interventions are highly effective in treating skin and joint inflammation, they carry clinical risks, such as increased susceptibility to Candida infections due to the loss of Th17-mediated antifungal protection [PubMed: 29051808]. Because the 'Th17 response' represents a complex biological process involving multiple cytokines and receptors rather than a single molecule, it is categorized as a pathway rather than an individual drug target.

Other names

Th17 axisTh17 pathwayInterleukin-17/Interleukin-23 axisT-helper 17 cell-mediated response

Modulation of the Th17 axis is achieved through the neutralization of effector cytokines (IL-17A, IL-17F) or upstream regulatory cytokines (IL-23), or via the blockade of their respective receptors to inhibit downstream pro-inflammatory signaling and T-cell maintenance.