T cells from lymphoepithelial thymoma produce a biochemical variant of IL-2

The supernatant of TE+ lymphocytes isolated by density gradient from a lympho-epithelial thymoma contained a biochemical variant of T cell growth factor (IL-2). This protein showed two peaks with an apparent molecular weight of 18 and 28 kd by Sephadex G 100 chromatography. Further purification was achieved by DEAE Sephacel and CM Sepharose ion-exchange chromatography. By isoelectric focusing the isoelectric point was found to differ from that of normal. IL-2. Based on these results, the IL-2 variant appears to be a new kind of lymphokine distinguishable from normal IL-2 and similar to a TCGF (L-TCGF peak II) purified from the malignant T cell clone HUT 102.