 Lymphocyte T-cell immunomodulator, or T-4 immune stimulating factor (TISF), is a single chain polypeptide that is a strongly cationic glycoprotein and is purified with cation exchange resin.Purification of protein from bovine-derived type II thymic epithelial cell supernatants produces a substantially homogeneous factor, free of extraneous materials.The bovine protein is homologous with other mammalian species and is a homogeneous 50 kDa glycoprotein with an isoelectric point of 6.5.