IL7 is a secreted cytokine of the hemopoietin family that primarily affects early B and T cells and plays an important role in stimulating the proliferation of lymphoid progenitors. IL7 is produced by stromal epithelial cells of the thymus, bone marrow, and intestines. Human and murine IL7 share 60% sequence homology at the primary level and known to exhibit cross species activity. Designated CD127, the human IL7 receptor is a strongly glycosylated membrane protein of 76 kDa. Recombinant Human IL7 is expressed in human 293 cells as a monomeric glycoprotein, with three seperate bands of 19, 25, and 30 kD under reducing conditions on gel.