This mouse monoclonal antibody (clone MT8G10) reacts with human interleukin 2 (IL-2). IL-2 is an ~16 kDa cytokine composed of a four-alpha-helix bundle (Arenas-Ramirez et al.), produced primarily by CD4+ T helper (Th) cells and to a lesser degree by CD8+ T cells, natural killer (NK) cells, and NK T cells (Boyman & Sprent). It binds to the IL-2 receptor α (IL-2Rα; CD25), which complexes with IL-2Rꞵ (CD122) and γc (CD132) subunits (Malek & Castro) and leads to the activation of JAK1/3, P13K-AKT, and MAPK signaling pathways (Arenas-Ramirez et al.). IL-2 mediates T cell growth and proliferation, facilitates the differentiation of CD4+ T cells to Th1 and Th2 cells, promotes CD8+ T cell and NK cell cytolytic activity, and drives the development of CD4+FOXP3+ regulatory T cells (Liao et al.).