title: A factor capable of enhancing virus replication appearing in parainfluenza virus type 1 (HVJ)-infected allantoic fluid.
mesh_terms: D000818:Animals; D002642:Chick Embryo; D003168:Complement Fixation Tests; D005321:Extraembryonic Membranes; D006384:Hemagglutination; D066298:In Vitro Techniques; D007372:Interferons; D018108:Respirovirus / Q000276:immunology*; D014776:Virus Cultivation
chemical_list: D007372:Interferons