title: Isolation and characterization of defective interfering particle of Newcastle disease virus.
abstract: Newcastle disease virus grown in embryonated eggs was separated and purified by sucrose density gradient centrifugation into two distinct type of particles, B and T, the former being normal virus particles with high activities of hemagglutination, hemolysis, neuraminidase and infectivity, the latter being non-infectious virus particles with low activities of hemolysis and neuraminidase but high hemagglutination activity. B and T particles were shown to share a common antigen by immunodiffusion test. T particles were deficient in viral RNA, since they contained only 13s RNA in a small amount, whereas B particles possessed a large amount of 57s RNA and a small amount of 13s RNA. T particles interfered with the multiplication of normal Newcastle disease virus in primary cultures of chick embryo cells.
mesh_terms: D000818:Animals; D000956:Antigens, Viral; D002499:Centrifugation, Density Gradient; D005591:Chemical Fractionation; D002642:Chick Embryo; D006386:Hemagglutination Tests; D006461:Hemolysis; D009522:Newcastle disease virus / Q000276:immunology / Q000302:isolation & purification* / Q000648:ultrastructure; D012313:RNA / Q000378:metabolism; D011817:Rabbits
chemical_list: D000956:Antigens, Viral; D012313:RNA