The IL17A is a pro-inflammatory cytokine that, although expressed by several cell types, defines the T helper 17 (TH17) cell subset. IL17A activates signal transduction pathways that recruit neutrophils, promote the production of antimicrobial factors, and drive the inflammatory pathology associated with autoimmune disorders.

The Il17a^EGFP mice were developed by Beijing Biocytogen Co., Ltd. An IRES-EGFP-SV40-polyA signal sequence cassette was inserted after the stop codon of the Il17a gene using C57BL/6-derived embryonic stem (ES) cells. This strain was maintained on a C57BL/6 genetic background.

Fluorescence can be observed in some intraepithelial lymphocytes (IELs) of the small intestine without stimulation. Naive CD4+ T cells stimulated with plate-bound anti-CD3/anti-CD28 in the presence of transforming growth factor, beta 1 (TGFB, 1 ng/ml) and interleukin 6 (IL6, 20 ng/ml) show increased fluorescence associated with IL17A production. Normal levels of IL17A are expressed.