The PC-61.5.3 monoclonal antibody reacts with mouse IL-2Rα also known as CD25, Ly-43, p55, or Tac.The PC-61.5.3 antibody has been shown to inhibit the binding of IL-2 to both the low and high affinity IL-2 receptor forms. Additionally, the PC-61.5.3 antibody is commonly used to deplete CD4+FoxP3+ T regulatory cells in vivo.