title: Influence of the Epstein-Barr virus nuclear antigen EBNA 2 on the growth phenotype of virus-transformed B cells.
abstract: Epstein-Barr virus (EBV) isolates show sequence divergence in the BamHI YH region of the genome which encodes the nuclear antigen EBNA 2, a protein thought to be involved in the initiation of virus-induced B-cell transformation; type A isolates (such as B95-8 EBV) encode a 82- to 87-kilodalton EBNA 2A protein, whereas type B isolates (such as AG876 EBV) encode an antigenically distinct 75-kilodalton EBNA 2B protein. In the present work 12 type A isolates and 8 type B isolates have been compared for their ability to transform resting human B cells in vitro into permanent lymphoblastoid cell lines. Although the kinetics of initial focus formation was not markedly dependent upon the EBNA 2 type of the transforming virus, on subsequent passage type A virus-transformed cells (type A transformants) yielded cell lines much more readily than did type B transformants. Direct comparison between the two types of transformant revealed clear differences in several aspects of growth phenotype. Compared with type A transformants, cell lines established with type B virus isolates consistently displayed an unusual growth pattern with poor survival of individual cells shed from lymphoblastoid clumps, a lower growth rate and a greater sensitivity to seeding at limiting dilutions, and a significantly lower saturation density that could not be corrected by supplementation of the medium with culture supernatant containing B-cell growth factors. This is the first direct evidence that, in EBV-transformed B-cell lines, the EBNA 2 protein plays a continuing role in determining the cellular growth phenotype.
mesh_terms: D000483:Alleles; D000956:Antigens, Viral / Q000502:physiology*; D001402:B-Lymphocytes / Q000166:cytology / Q000382:microbiology*; D002455:Cell Division; D002460:Cell Line; D002472:Cell Transformation, Viral; D019309:Epstein-Barr Virus Nuclear Antigens; D004854:Herpesvirus 4, Human / Q000145:classification / Q000502:physiology*; D006801:Humans; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D014779:Virus Replication
chemical_list: D000956:Antigens, Viral; D019309:Epstein-Barr Virus Nuclear Antigens; D013755:Tetradecanoylphorbol Acetate