title: Isolation of an "antigenic variant" of West Nile virus, originating from a chronic infection of the virus in LLC cells.
mesh_terms: D000818:Animals; D046508:Culture Techniques; D004668:Encephalitis Viruses / Q000276:immunology*; D005779:Immunodiffusion; D051379:Mice; D014902:West Nile virus / Q000276:immunology