IL15R is a heterotrimer of IL15RA, IL2RB and IL2RG. IL-15RA, also known as CD215, IL-15 R alpha, is a widely expressed 60 kDa transmembrane glycoprotein. High-affinity receptor for interleukin-15. Can signal both in cis and trans where IL15R from one subset of cells presents IL15 to neighboring IL2RG-expressing cells. Expression of different isoforms may alter or interfere with signal transduction. An interleukin (IL)-15 superagonist/IL-15 receptor α fusion complex (IL-15SA/IL-15RA; ALT-803) activates the IL-15 receptor on CD8 T cells and NK cells, and has shown significant anti-tumor. Signal transduction involves SYK. Higher levels of soluble sIL-15RA form in comparison with membrane-bound forms is present in all brain structures.