title: Contribution to the problem of purity of interferon preparations.
mesh_terms: D000917:Antibody Formation; D000956:Antigens, Viral; D002845:Chromatography; D004591:Electrophoresis, Polyacrylamide Gel; D007106:Immune Sera; D005779:Immunodiffusion; D007372:Interferons / Q000096:biosynthesis / Q000302:isolation & purification / Q000592:standards*; D007739:L Cells / Q000378:metabolism; D009522:Newcastle disease virus / Q000276:immunology
chemical_list: D000956:Antigens, Viral; D007106:Immune Sera; D007372:Interferons