CD4+ T follicular helper cell activation (Tfh activation)

CD4+ T follicular helper (Tfh) cell activation is a multifaceted biological process where naive CD4+ T cells differentiate into a specialized subset that resides in secondary lymphoid organs to facilitate B cell maturation [Vinuesa et al., Nature Reviews Immunology, 2016]. This process is driven by the master transcription factor BCL6 and requires specific signals from antigen-presenting cells, including ICOS-ICOSL and CD28-CD80/86 costimulation [Crotty, Immunity, 2019]. Activated Tfh cells express the chemokine receptor CXCR5, which allows them to migrate into B cell follicles where they provide critical 'help' through the secretion of IL-21 and the expression of CD40L [Ueno et al., Nature Immunology, 2015]. Dysregulation of Tfh activation is a hallmark of autoantibody-mediated diseases like systemic lupus erythematosus, making the molecules involved in this process high-priority therapeutic targets [Tangye et al., Journal of Experimental Medicine, 2013]. Conversely, enhancing Tfh activation is a primary strategy in vaccine development to ensure the production of high-affinity, long-lived antibody responses [Spolski & Leonard, Nature Reviews Immunology, 2014].

Other names

T follicular helper cell differentiationTfh cell activationFollicular T-helper cell activationCD4+ CXCR5+ T cell activation

Drugs modulating this process typically act by blocking costimulatory signals (e.g., CD28/CTLA-4, ICOS/ICOSL, CD40/CD40L) or neutralizing cytokines (e.g., IL-21, IL-6) required for Tfh cell differentiation and maintenance [Crotty, Immunity, 2019; Ueno et al., Nature Immunology, 2015].