title: Macrophage activating factor is not identical with immune interferon or a factor inducing differentiation of mouse myeloid leukemic cells.
abstract: Conditioned media of mitogen- or antigen-stimulated spleen cells have been found to contain various lymphokines including macrophage activating factor (MAF), immune interferon (IFN-gamma) and a factor inducing differentiation of mouse myeloid leukemic M1 cells into macrophages and granulocytes (D-factor). We examined the properties and mutual relations of these lymphokines. Conditioned media of concanavalin A (Con A)-stimulated spleen cells and of purified protein derivative (PPD)-stimulated Bacillus Calmette-Guérin (BCG)-immune spleen cells contained the activities of D-factor, MAF and IFN. These lymphokines were similarly eluted on Sephadex G-100 in a peak corresponding to a molecular weight of 40,000 approximately 60,000. However, a rapidly eluted fraction contained MAF but not activities of D-factor and IFN. Treatment of conditioned medium of Con A-stimulated spleen cells at pH 2 abolished the activities of MAF and IFN but did not affect the activity of D-factor. Moreover, addition of cytochalasin B suppressed the productions of MAF and IFN but not that of D-factor by Con A-stimulated spleen cells. Antiserum against mouse IFN-gamma neutralized IFN activity but not MAF activity in the conditioned medium of Con A-stimulated spleen cells. These results indicate that D-factor, MAF and IFN-gamma are all distinct substances.
mesh_terms: D000818:Animals; D002454:Cell Differentiation / Q000187:drug effects*; D003208:Concanavalin A / Q000494:pharmacology; D006023:Glycoproteins / Q000302:isolation & purification*; D006131:Growth Inhibitors; D007371:Interferon-gamma / Q000302:isolation & purification*; D015850:Interleukin-6; D053605:Leukemia Inhibitory Factor; D007951:Leukemia, Myeloid / Q000276:immunology*; D008222:Lymphokines / Q000302:isolation & purification*; D016215:Macrophage-Activating Factors; D008264:Macrophages / Q000276:immunology*; D051379:Mice; D008970:Molecular Weight; D013154:Spleen / Q000166:cytology / Q000276:immunology
chemical_list: D006023:Glycoproteins; D006131:Growth Inhibitors; D015850:Interleukin-6; D053605:Leukemia Inhibitory Factor; C507838:Lif protein, mouse; D008222:Lymphokines; D016215:Macrophage-Activating Factors; D003208:Concanavalin A; D007371:Interferon-gamma