I.K. Malashenkova (1), G.V. Kazanova (1), N.A. Didkovsky (2)
1 -National Research Centre «Kurchatov Institute», Russian Federation, 123182, Moscow, Akademika Kurchatova Square, 1;
2 -Scientific-Research Institute of Physical Chemical Medicine, Russian Federation, 119992, Moscow, Malaya Pirogovskaya Str., 1-a

IL15 proves to be a cytokine that important for innate as well as for adaptive immunity. It is one of the key factors of cell-mediated antiviral response. In this review we touch upon its primary, secondary and tertiary structure and functions, characteristics of its receptor complex and features of its signaling in various subpopulations of immune cells. We also discuss the role of alternative splicing and glycosylation in its functioning. IL15 is structurally and functionally homological to IL2 and employs IL-2Rβ and IL-2Rγ receptor chains for signaling. IL15 can affect various immune and non-immune cells via signaling cascades such as JAK-STAT and MAPK-ERK. For example, it is expressed by various antigen-presenting cells and plays an important role in their vital activity. IL15 trans-presentation signaling is essential for the development, functional activity and homeostasis of NK, Т-NK, immune memory CD8+ T-cells and intraepithelial lymphocytes. IL15 Rα is widely expressed by human cells, and anti-inflammatory, proliferative and anti-apoptotic effects mediated by IL15 are important for maturation, differentiation and survival of cells of various types of the skin and the internal organs. Thus, disturbances of IL15 expression , regulation, signaling make this cytokine an active a participant in pathogenesis of a number of inflammatory, autoimmune and lymphoproliferative diseases.
IL15, IL-2Rβ, IL-15Rα, trans-presentation, dendritic cells, NK, T-NK, immune memory CD8+ T-cells, intraepithelial lymphocytes, homeostasis, apoptosis