PARTIAL-PURIFICATION AND CHARACTERIZATION OF HUMAN LYMPHOCYTE COLONY ENHANCING FACTOR (LCEF)

Abstract

The cloning potential of PHA[phytohemagglutinin]-treated T [thymus-derived] cells is significantly enhanced when lymphocyte culture fluid (LCF) from mitogen-treated lymphocytes is added to the soft agar culture system. The mitogens seem to stimulate the release of a lymphocyte colony enhancing factor (LCEF) into the culture medium. A study of the physico-chemical properties of the LCEF revealed that it is a nondialyzable, heat-labile molecule which migrates in the haptoglobin (2-2) post-transferrin region in acrylamide electrophoresis. It is stable to RNase and DNase but labile to papain and trypsin. The LCEF was partially purified from the crude LCF using a sequence of techniques: ammonium sulfate precipitation, DEAE-cellulose and Bio-Gel P-150 chromatography and disc electrophoresis. The MW of the purified LCEF, determined from gel filtration chromatography, was 90,000-110,000.