title: Lymphoblastoid cells transfected with c-myc: downregulation of EBV-lytic antigens and impaired response of autologous CD4+ T cells in vitro.
abstract: Normal EBV-positive lymphoblastoid B-cell lines (LCL) were transfected with vectors containing the c-myc oncogene (pHEBO-E(mu)-myc) or control vectors (pHEBO-E(mu)) and analyzed for the expression of EBV-lytic and latent antigens. While EBV-latent antigens were normal in the c-myc transfectants, there was an almost complete downregulation of EBV-lytic antigens, including BZLF1, EA(D), gp340 and VCA. These observations were consistently repeated on 6 different LCLs transfected with c-myc. Unlike control LCLs, the c-myc transfectants did not release infectious EBV. PCR analysis demonstrated that BZLF1 mRNA was virtually absent in c-myc transfectants, possibly suggesting that the deregulated c-myc imposed a block in the EBV-lytic cycle at this particular level. c-myc transfectants failed to sustain the proliferative response of autologous CD4+ T-cell clones with specificity for EBV-lytic antigens. However, they regained this capacity after incubation with ultraviolet-inactivated EBV or gp340 antigen in vitro, also indicating that their antigen-presenting capacities were not impaired. c-myc transfectants failed to elicit a secondary proliferative response by autologous CD4+ T cells purified from the peripheral blood of EBV-seropositive donors. Exposure of c-myc transfectants to UV-inactivated EBV again resulted in a proliferative CD4+ T-cell response comparable to that elicited by the control LCLs. Collectively, our data provide evidence for the remarkable ability of an oncogene to influence the life cycle of a virus and to modify the antigenicity of the infected cells.
authors.affiliation: Istituto Nazionale per la Ricerca sul Cancro, IST, Genoa, Italy.
authors.forename: F
authors.initials: F
authors.lastname: Fais
authors.forename: G
authors.initials: G
authors.lastname: Cutrona
authors.forename: M
authors.initials: M
authors.lastname: Ulivi
authors.forename: S
authors.initials: S
authors.lastname: Roncella
authors.forename: M C
authors.initials: MC
authors.lastname: Gagliardi
authors.forename: P
authors.initials: P
authors.lastname: Cornaglia-Ferraris
authors.forename: M
authors.initials: M
authors.lastname: Rowe
authors.forename: V
authors.initials: V
authors.lastname: Barnaba
authors.forename: M
authors.initials: M
authors.lastname: Ferrarini
mesh_terms: D001402:B-Lymphocytes / Q000166:cytology* / Q000502:physiology; D015153:Blotting, Western; D015496:CD4-Positive T-Lymphocytes / Q000502:physiology*; D002455:Cell Division / Q000502:physiology; D002460:Cell Line; D015536:Down-Regulation; D016259:Genes, myc / Q000276:immunology*; D004854:Herpesvirus 4, Human / Q000276:immunology*; D006801:Humans; D007156:Immunologic Memory / Q000502:physiology; D014162:Transfection