Interleukin 9 (IL-9) is cytokine produced by a subgroup of helper T cells, known as Th2 cells. IL-9 signals through its receptor IL-9R to induce cell prolife ion and survival. Genetically, IL-9 has been identified as a gene associated with asthma. Recombinant IL-9 is a non-glycosylated Protein, containing 127 amino acids, with a molecular weight of 14 kDa