Recombinant protein. The extracellular domain of human IL-2 aa 21-153 mutant pH-resistant Switch-2 containing mutations T37H, R38L, T41S, F42Y, and K43G is fused at the C-terminus to the Fc portion of human IgG1 Knobs-into-Holes technology see reference J.B. Ridgway, et al. Protein Eng. 9, 617 1996. Source HEK 293 cells. Lyophilized. Contains PBS. Interleukin-2 IL-2 is a 133 amino acid glycoprotein with one intramolecular disulfide bond and variable glycosylation. It is secreted by activated T cells and induces proliferation and maturation of activated T cells, natural killer cells and lymphokine activated killer cells. IL-2 also stimulates proliferation of antibody-producing B cells, activates neutrophils and induces mononuclear cells to secrete IFN-gamma and TNF-alpha and -beta.