Helios Armenian Hamster anti-Human, Alexa Fluor 647, Clone: 22F6, BD

The 22F6 monoclonal antibody specifically binds to mouse and human Helios. Helios is a member of the Ikaros family of zinc-finger transcription factors, which play important roles in hematopoietic cell development and tumor suppression. Helios expression is restricted to the earliest stages of embryonic hematopoiesis, a variety of epithelial tissues and is notably increased in thymic-derived regulatory CD4+Foxp3+ T (Treg) cells. Its high expression levels in Treg cells are independent from Foxp3 and are believed to contribute, along with other transcription factors, to the phenotypic stability of natural regulatory T cells. Accordingly, it has been demonstrated that Helios directly stimulates Foxp3 transcription while it inhibits ll2 gene expression, contributing for the maintenance of cellular anergy. Helios is also differentially expressed during negative and positive selection in the thymus, marking CD4+ autoreactive cells for deletion. Helios may possibly play roles in T cell activation, since it is upregulated in Th2 and Tfh cells. Despite these roles in T cell development and function, Helios genetic ablation in mice revealed no significant abnormalities in Treg or other T cell subsets. This finding suggests that other Ikaros family members may play redundant roles.