title: Purification and biochemical characterization of human lymphocyte mitogenic factor (LMF).
abstract: Supernatants of human T lymphocytes stimulated by TT antigen release two factors that induce mitogenesis in autologous and allogeneic B lymphocytes. These factors are precipitated by 60% ammonium sulfate and 50% ethanol, and are both destroyed by heating to 70 degrees C for 5 min. By equilibrium ultracentrifugation there was a peak of mitogenic activity in the fraction with a specific gravity of 1.3147 corresponding to a partial specific volume of 0.761. After ultrafiltration through an Amicon XM50 membrane, the concentrate was chromatographed on a Sephadex G-200 column. Mitogenic activity was found only in the post-albumin fraction. When the post-albumin fraction was run on an isoelectrofocusing column, two distinct mitogenic factors were identified. The major peak of mitogenic activity (LMF) had a pI of 6.68 +/- 0.05 and the minor peak (MMF) had a pI OF 7.27 +/- 0.05. Amino acid analysis of LMF identified it as a protein and PAGE showed that LMF probably was a tetramer with a m.w. of 80,000.
mesh_terms: D000596:Amino Acids; D000645:Ammonium Sulfate / Q000494:pharmacology; D011232:Chemical Precipitation; D002850:Chromatography, Gel; D004591:Electrophoresis, Polyacrylamide Gel; D000431:Ethanol / Q000494:pharmacology; D006358:Hot Temperature; D006801:Humans; D007376:Interleukin-2 / Q000302:isolation & purification*; D007525:Isoelectric Focusing; D008214:Lymphocytes / Q000276:immunology; D008222:Lymphokines / Q000302:isolation & purification*; D008970:Molecular Weight; D014461:Ultracentrifugation; D014462:Ultrafiltration
chemical_list: D000596:Amino Acids; D007376:Interleukin-2; D008222:Lymphokines; D000431:Ethanol; D000645:Ammonium Sulfate