title: Suppressor cell-inducing factor: a new lymphokine secreted by a natural suppressor cell line with natural cytotoxic activity. I. Purification to apparent homogeneity and initial characterization of suppressor cell-inducing factor.
abstract: The lymphokine suppressor cell-inducing factor (SIF), obtained from 15 liters of serum-free culture supernatants of the natural suppressor cell line, M1-A5, has been purified to apparent homogeneity by a combination of gel filtration, ion exchange chromatography, and reverse-phase-HPLC. Purity of SIF was assessed by the migration of the factor as a single band on SDS-PAGE, and the elution from reverse-phase-HPLC column as a single and sharp peak. SIF activity was retained after both procedures. Two protein factors with SIF activity were isolated from M1-A5 culture supernatants. The first protein factor (SIF alpha) had a Mr of 43 kDa, and the second protein factor (SIF beta) had a Mr of 6 kDa. Final purification of SIF alpha yielded 5 micrograms protein with specific activity of 4 x 10(6) U/mg protein. Final purification of SIF beta yielded 40 micrograms protein with specific activity of 7.5 x 10(7) U/mg protein. The relationship between SIF alpha and SIF beta, as well as the relationship with other suppressor factors, will be addressed.
authors.affiliation: Department of Pharmacology, Dalhousie University, Halifax, Nova Scotia, Canada.
authors.forename: W Y
authors.initials: WY
authors.lastname: Almawi
authors.forename: P J
authors.initials: PJ
authors.lastname: Dolphin
authors.forename: R L
authors.initials: RL
authors.lastname: Thies
authors.forename: W R
authors.initials: WR
authors.lastname: McMaster
authors.forename: J G
authors.initials: JG
authors.lastname: Levy
authors.forename: B L
authors.initials: BL
authors.lastname: Pope
mesh_terms: D000596:Amino Acids / Q000032:analysis; D000818:Animals; D002460:Cell Line; D002850:Chromatography, Gel; D002851:Chromatography, High Pressure Liquid; D002852:Chromatography, Ion Exchange; D003470:Culture Media; D003602:Cytotoxicity, Immunologic; D005312:Fetal Blood / Q000502:physiology; D007694:Killer Cells, Natural / Q000276:immunology / Q000378:metabolism*; D008222:Lymphokines / Q000302:isolation & purification* / Q000502:physiology; D008297:Male; D051379:Mice; D008811:Mice, Inbred DBA; D008970:Molecular Weight
chemical_list: D000596:Amino Acids; D003470:Culture Media; D008222:Lymphokines