Preparation of IL-15 Superagonist Complex

Mouse IL-15 Receptor α subunit Fc chimera (IL-15Rα) was obtained from R&D systems (Minneapolis, MN, Cat. No. 551-MR-100). Recombinant IL-15 was purchased from eBiosciences (San Diego, CA, Cat no. 34-8151-85). IL-15 superagonist was prepared as described previously [20 (link),41 (link)]. Briefly, 20 μg of IL-15 and 90 μg of IL-15Rα were incubated in 400 μL of sterile phosphate buffered saline (PBS) at 37°C for 20 min to form the IL-15/IL-15Rα complex (IL-15 SA). That preparation was further diluted with sterile PBS to prepare a stock concentration of 2 μg IL-15 SA and stored at -80°C for future use.