IL-13 is an immunoregulatory cytokine produced primarily by activated Th2 lymphocytes. IL-13 shares 30% amino acid sequence homology with IL-4 and demonstrates similar biological activities. The biological activities of IL-13 include: suppression of macrophage cytotoxic activity, upregulation of IL-1RA expression, and suppression of proinflammatory cytokine secretion. The JES10-5A2 antibody reacts with human interleukin-13 (IL-13). The JES10-5A2 antibody can neutralize the bioactivity of natural or recombinant IL-13.