A large scale method of separating multiple lymphokines secreted by the murine EL-4 thymoma

The in vivo administration of lymphokines is a new approach to immunotherapy with possible applications to the treatment of tumors and infectious processes. These lymphokines are produced in very small quantities and purification of these molecules has proven difficult. A rapid two step method was used to isolate different lymphokines from large quantities of conditioned media produced by the murine EL-4 cell line. Interleukin-2 (IL-2), colony stimulating factor (CSF) and macrophage activating factor (MAF) are lymphokines with distinct biologic activities and are secreted by the EL-4 cell line. Their isolation involved initial batch purification on trimethylsilyl-controlled pore glass beads followed by reversed phase high pressure liquid chromatography. Recovery of IL-2 activity was >100% of initial activity. The specific activity of the purified IL-2 ranged from 2x10⁶ to 3.6x10⁷ U/mg protein. Colony stimulating factor (CSF) and macrophage activating factor (MAF) were also separated on the chromatographic columns. This technique is useful for the purification of large quantities of these lymphokines which have potential in vivo applications.