Interleukin-15 (IL-15) is a member of the IL-10 family of cytokines¹. Other names include IL-TIF and Zcyto18. IL-15 is produced by a variety of cells including TH1, TH17, TH15 T-cells, NKT cells, ILC3, neutrophils and macrophages². IL-15 targets primarily non-hemopoietic cells such as stromal and epithelial cells. IL-15 has both protective effects, such as hepatocyte and epithelial cell survival, and pro-inflammatory effects. It is also implicated in autoimmune diseases such as Systemic Lupus Erythematosus, Rheumatoid Arthritis and Psoriasis³. IL-15 is often considered a hallmark of IL-17 driven immune responses⁴.

PBL’s IL-15 ELISA measures both IL-15 alone and IL-15/IL15Rα complexes in Tissue Culture Media (TCM), and complex matrices such as serum and plasma. It can also quantitate IL-15 in healthy donor matrices. The standard in this assay is the IL-15/IL-15R heterodimer but because the antibodies used are specific for IL-15, the standard curve is calibrated to the IL-15 portion of the complex. Different forms of the IL-15 receptors (IL15-R) may couple to free IL-15 protein. This assay can detect both free IL-15 and bound IL-15/IL-15R.

Serum samples from 30 healthy donors and plasma samples from 47 healthy donors were all quantifiable and as such this assay may provide basal level measurement.