|Detection of Human IL‑2 by Western Blot. Western blot shows lysates of monensin treated human peripheral blood mononuclear cells (PBMCs)with no additioan treatment (-) or additionaly treated (+) with 0.5 ug/mL calcium ionomycin (Iono) and 50 ng/mL PMA overnight. PVDF membrane was probed with 2 µg/mL of Goat Anti-Human IL‑2 Polyclonal Antibody (Catalog # AB-202-NA) followed by HRP-conjugated Anti-Goat IgG Secondary Antibody (Catalog # HAF017). A specific band was detected for IL‑2 at approximately 14 kDa (as indicated). This experiment was conducted under reducing conditions and using Immunoblot Buffer Group 1.|
|Cell Proliferation Induced by IL‑2 and Neutralization by Human IL‑2 Antibody. Recombinant Human IL‑2 (Catalog # 202-IL) stimulates proliferation in the CTLL‑2 mouse cytotoxic T cell line in a dose-dependent manner (orange line). Proliferation elicited by Recombinant Human IL‑2 (2 ng/mL) is neutralized (green line) by increasing concentrations of Goat Anti-Human IL‑2 Polyclonal Antibody (Catalog # AB-202-NA). The ND50 is typically 0.2-0.8 µg/mL.|
Interleukin-2 (IL-2) is a O-glycosylated, four alpha -helix bundle cytokine that has potent stimulatory activity for antigen-activated T cells. It is expressed by CD4+ and CD8+ T cells, gamma δ T cells, B cells, dendritic cells, and eosinophils (1-3). Mature human IL-2 shares 56% and 66% aa sequence identity with mouse and rat IL-2, respectively. Human and mouse IL-2 exhibit cross-species activity (4). The receptor for IL-2 consists of three subunits that are present on the cell surface in varying preformed complexes (5-7). The 55 kDa IL-2 R alpha is specific for IL-2 and binds with low affinity. The 75 kDa IL-2 R beta, which is also a component of the IL-15 receptor, binds IL-2 with intermediate affinity. The 64 kDa common gamma chain gamma c/IL-2 R gamma, which is shared with the receptors for IL-4, -7, -9, -15, and -21, does not independently interact with IL-2. Upon ligand binding, signal transduction is performed by both IL-2 R beta and gamma c. IL-2 is best known for its autocrine and paracrine activity on T cells. It drives resting T cells to proliferate and induces IL-2 and IL-2 R alpha synthesis (1, 2). It contributes to T cell homeostasis by promoting the
Fas-induced death of naïve CD4+ T cells but not activated CD4+ memory lymphocytes (8). IL-2 plays a central role in the expansion and maintenance of regulatory T cells, although it inhibits the development of Th17 polarized cells (9 - 11). Thus, IL-2 may be a key cytokine in the natural suppression of autoimmunity (12, 13).