title: Antigenic shift of visna virus in persistently infected sheep.
abstract: Visna viruses isolated from persistently infected sheep were antigenically distinct from the plaque-purified virus used for inoculation. The selection of antigenic variants under antibody pressure, thought to occur in vivo, was reproduced in sheep cell cultures inoculated with plaque-purified visna virus and maintained in antibody. Antigenic shift may be a mechanism for persistence of virus in slow or recurrent viral infections.
mesh_terms: D000818:Animals; D000956:Antigens, Viral / Q000032:analysis*; D007962:Leukocytes / Q000276:immunology / Q000382:microbiology; D011648:Pulmonary Adenomatosis, Ovine / Q000276:immunology*; D012328:RNA Viruses / Q000276:immunology*; D012756:Sheep; D014790:Visna-maedi virus / Q000276:immunology*
chemical_list: D000956:Antigens, Viral