Epstein-Barr virus (EBV) can immortalize B-cll cells activated by cytokines

B-type of chronic lymphocytic leukemia (B-CLL) cells are inert to the potent transforming action of Epstein-Barr virus (EBV). The mitogenic action of Staphylococcus aureus Cowan I (SAC), MP6-thioredoxin, and interleukin 2 (IL-2), agents previously shown to induce proliferation in normal as well as in B-CLL cells, lifted this block, and EBV-positive cell lines could be established. It was not possible to establish cell lines of leukemic origin from cultures that were incubated with EBV alone or cytokine mix alone. CLL-cells infected with EBV only, expressed the viral nuclear antigen complex (EBNA), but not the viral latent membrane protein (LMP). They were not activated as measured by cell size and 3H-thymidine incorporation. In contrast, cells incubated with EBV and cytokine mix expressed both EBNA and LMP in parallel with enlargement and increased 3H-thymidine incorporation. These results emphasize that LMP expression is a prerequisite for growth transformation and immortalization and that cytokine activation signals are required for its expression in B-CLLs. Cells incubated with SAC/MP6-thioredoxin/IL-2 did not express any of the viral antigens, but were activated with regard to the mentioned parameters. Nine cell lines were established from six patients. From each of the three patients, we obtained 'twin'-pair lines: one corresponding to the malignant cell and the other to a normal B-lymphoblastoid cell. Thus, malignant and normal B-cell counterparts, from the very same donor, are at hand for comparative studies. The cell lines have been carried out for more than 12 months in culture. We conclude that B-CLL that are refractory to EBV-transformation can be rendered susceptible through in vitro cytokine activation.     

Functional diversity of the CD8(+) T-cell response to Epstein-Barr virus (EBV): implications for the pathogenesis of EBV-associated lymphoproliferative disorders

Epstein-Barr virus (EBV)-specific CD8(+) cytotoxic T cells are thought to be critical for the control of EBV, which persists in healthy individuals as a latent infection of B cells. However, recent observations have indicated that CD8(+) T-cell responses are not uniformly cytotoxic and that CD8(+) T cells may be subdivided into type 1 and type 2 subsets that parallel the classically described Th1 and Th2 subsets of CD4(+) T cells. Using two-color flow cytometric analysis of intracellular cytokine expression at the single-cell level, we have identified two distinct but overlapping subsets of EBV-specific CD8(+) T cells, the first of which expressed high levels of interferon gamma (IFNgamma), but little or no interleukin-4 (IL-4), whereas the second subset was IFNgamma+/IL-4(+) double-positive. A significant proportion of EBV-specific CD8(+) T cells also expressed IL-13. Subsequent analysis of a panel of 27 EBV-specific CD8(+) T-cell clones showed inverse relationships between EBV-specific cytotoxicity and secretion of IL-4, IL-10, and IFNgamma, respectively. IL-10 was not secreted by the 11 most strongly cytotoxic clones, suggesting that IL-10 secretion may provide a functional definition of an EBV-specific type 2 CD8(+) T-cell subset with reduced EBV-specific cytotoxicity. Finally, we have demonstrated that EBV-specific CD8(+) T cells that express type 2 cytokines possess the ability to activate resting B cells. EBV-specific CD8(+) T cells thus have the potential to reactivate latent EBV infection in vivo and may contribute to the development of EBV-associated lymphoproliferative disorders and lymphoma.     

Epstein-Barr virus (EBV) and Hodgkin''s disease in a multi-ethnic population in Malaysia

The plant pathogenic fungus Verticillium dahliae produced extracellular alkaline protease activity when grown in liquid medium supplemented with a protein source. A serine protease was purified 80-fold in a single step, using cation-exchange chromatography, from the filtrate of cultures grown with skim milk as a protein source. N-terminal amino acid sequence analysis of the 30-kDa protein (VDP30) that copurified with the serine protease activity suggested that VDP30 is a trypsin-like protein. The purified enzyme hydrolyzed the synthetic substrate N alpha-benzoyl-DL-arginine p-nitroanilide hydrochloride (BAPNA), and the activity on BAPNA was inhibited by leupeptin, further verifying the trypsin-like nature of the enzyme.     

EB病毒膜潜伏蛋白LMP-1筛选鼻咽癌的初步结果

Objective: Early diagnosis of nasopharyngeal carcinoma (NPC) is an important method to improve the survival rate. However, the sensitivity and specificity of the screening protocols which was widely used in clinic now are considered to be unsatisfactory. Epstein-Barr virus (EBV)-encoded latent membrane protein-1 (LMP-1)is one of the proteins that have been suggested to be a classic oncogene with transformation properties. The current study set out to discuss the clinical significance of LMP-1 on the screening of NPC. Methods: Three hundred patients who visited our institution (Department of Radiation Oncology, Fujian Provincial Cancer Hospital, Fuzhou,China) with ENT symptoms between 2007 and 2008 were involved in this study, and all of them were agreed to be involved in this investigation. Not only did they undergo nasopharyngeal swab to obtain cells for the LMP-1 polymerase chain reaction (PCR) analysis, but also nasopharyngeal biopsy were taken to identify the diagnosis. Results: An amount of DNA that was sufficient for PCR was extracted from 243 (81%) swab samples, the positive rate of LMP-1 of those with non-nasopharyngeal carcinoma was 3.85% (4/108), which was much lower than those with nasopharyngeal carcinoma (P ＜ 0.05). By detecting LMP-1 in nasopharyngeal swabs, NPC was diagnosed with a sensitivity of 88.15% (119 of 135 patients), specificity of 96.30%(104 of 108 patients), a positive predictive value of 95.2% (119 of 123 patients), a negative predictive value of 86.67% (104of 120 patients), accuracy of 91.77%, and Youden index of 84.45%. Conclusion: The nasopharyngeal swab coupled with PCR-based EBV LMP-1 detection have high sensitivity and specificity, and also good repeatability, it could serve as part of the screening program for high-risk populations.     

Human herpesvirus-8 glycoprotein B interacts with Epstein-Barr virus (EBV) glycoprotein 110 but fails to complement the infectivity of EBV mutants

ortho-Phenylphenol (OPP), a fungicide and antibacterial agent with food residues, is carcinogenic to rat bladder. The present studies provide information on changes in urinary composition and urinary metabolites, urothelial cytotoxicity and regenerative hyperplasia, and DNA adducts in male F344 rats fed OPP. An initial experiment evaluated dietary doses of 0, 1,000, 4,000, and 12,500 ppm OPP fed for 13 weeks. There was no evidence of urinary calculi, microcrystalluria, or calcium phosphate-containing precipitate, but urothelial cytotoxicity and hyperplasia occurred at the highest dose only. In a second experiment, rats were fed dietary OPP levels of 0, 800, 4,000, 8,000, and 12,500 ppm. Urinary pH was > 7 in all groups. Urinary volume was increased at the 2 highest doses with consequent decreases in osmolality, creatinine, and other solutes. Total urinary OPP metabolite excretions were increased, mostly excreted as conjugates of OPP and of phenylhydroquinone. Free OPP or free metabolites accounted for less than 2% excreted in the urine without a dose response. Urothelial toxicity and hyperplasia occurred only at doses of 8,000 and 12,500 ppm. OPP-DNA adducts were not detected in the urothelium at any dose. In summary, OPP produces cytotoxicity and proliferation of the urothelium at dietary doses > or = 8,000 ppm without formation of urinary solids. The paucity of unconjugated metabolites and the lack of OPP-DNA adducts suggests that OPP is acting as a bladder carcinogen in male rats by inducing cytotoxicity and hyperplasia without it or its metabolites directly binding to DNA.     

Clonal propagation of Epstein-Barr virus (EBV) recombinants in EBV-negative Akata cells

We lack a host cell supporting an efficient lytic replication of Epstein-Barr virus (EBV). Recently, we isolated EBV-negative cell clones from the Akata cell line (referred as Akata- [N. Shimizu, A. Tanabe-Tochikura, Y. Kuroiwa, and K. Takada, J. Virol. 68:6069-6073, 1994). Since the parental Akata line is one of the highest EBV producers, we examined whether Akata- cells had become a good host for EBV propagation. The parental Akata cells have about 20 copies of EBV plasmid per cell. A drug resistance gene was inserted into one of them by homologous recombination. The resultant virus preparation, a mixture of wild-type and recombinant EBV, was used to infect Akata- cells. After incubation in the selective medium, drug-resistant Akata- cell clones were isolated and proved to be infected with recombinant EBV only. By treatment of the cells with antiimmunoglobulin antibodies, a large amount of recombinant EBV (i.e., more than 10 microg/1-liter culture) was produced. In contrast, three other B-lymphoma lines, BJAB, Ramos, and Louckes, were nonpermissive for virus replication. These results indicate that Akata- cells are suitable for propagation of recombinant EBV clonally, which becomes a powerful tool for determining EBV genetics and which makes it possible to use EBV as a vector for gene therapy.     

In vivo growth of Epstein-Barr virus transformed B cells with mutations in latent membrane protein 2 (LMP2)

Epstein-Barr virus (EBV) causes infectious mononucleosis in adolescents and is associated with malignant B lymphocyte proliferation in AIDS patients, patients undergoing immune suppression for organ transplantation, and SCID mice. In vitro, EBV transformed, latently infected lymphoblastoid B cell lines (LCLs) contain EBV episomes and express nine virus encoded proteins. Six are nuclear proteins (EBNAs) and three are the integral membrane proteins, LMP1, LMP2A, and LMP2B. To determine if LMP2 was essential for in vivo growth, SCID mice were injected with LCLs containing wild-type EBV (LMP2+) or with LCLs transformed with EBV containing mutations in either LMP2A or LMP2B (LMP2-). SCID mice injected with the LMP2+ or LMP2- LCLs were monitored for tumor development, length of time to tumor development, and phenotypic characterization of the resulting tumors. No difference was observed in any of the above parameters between LMP2+ and LMP2- LCLs demonstrating that LMP2 is not essential for the in vivo growth of EBV transformed B lymphocytes in SCID mice.     

The immunoreceptor tyrosine-based activation motif of Epstein-Barr virus LMP2A is essential for blocking BCR-mediated signal transduction

The study evaluates a comprehensive, ecological approach to behavioral family intervention with a family of a child with severe disabilities and severe problem behaviors. A multiple-baseline design across family routines assessed the functional relationship between parent implementation of a multicomponent intervention and improvement in child behavior and successful completion of routines. Results indicate durable improvements in child behavior and routine completion. Associated outcomes included generalized improvements in child behavior and enhanced activity patterns. Results verify the efficacy of the approach for ameliorating problem behaviors and empowering parents to build successful family routines. The value of collaborative research with families is briefly discussed.     

Absence of Epstein-Barr virus (EBV) in a gastrointestinal stromal cell tumour (GIST) in an adult human immunodeficiency virus-seropositive patient with past EBV infection

Gastrointestinal stromal cell tumours (GIST) of the small intestine are rare malignancies. Recently, an association of Epstein-Barr virus (EBV) with malignant stromal cell tumour in young people with AIDS and past EBV infection has been described. We describe a 33-year-old heterosexual male with asymptomatic human immunodeficiency virus (HIV) infection who had had an EBV infection in the past and who presented with an EBV-negative GIST. The association between EBV and malignant stromal cell tumours in young people with AIDS could not be reconfirmed in our adult patient. The relationship between EBV and malignant stromal cell tumours in AIDS patients and the possible pathogenetic role of EBV remains to be established, at least in adults.     

Epstein-Barr virus uses HLA class II as a cofactor for infection of B lymphocytes

Infection of B lymphocytes by Epstein-Barr virus (EBV) requires attachment of virus via binding of viral glycoprotein gp350 to CD21 on the cell surface. Penetration of the cell membrane additionally involves a complex of three glycoproteins, gH, gL, and gp42. Glycoprotein gp42 binds to HLA-DR. Interference with this interaction with a soluble form of gp42, with a monoclonal antibody (MAb) to gp42, or with a MAb to HLA-DR inhibited virus infection. It was not possible to superinfect cells that failed to express HLA-DR unless expression was restored by transfection or creation of hybrid cell lines with complementing deficiencies in expression of HLA class II. HLA class II molecules thus serve as cofactors for infection of human B cells.     

Epstein-Barr virus (EBV)-positive NK cell line YT, and ALL/LBL of NK-lineage

The YT cells, already known as natural killer (NK) line, were tested for Epstein-Barr virus (EBV). The simply maintained YT cells (YT-O) and the two different subclones showed and identical length of junctional DNA of terminal repeats in Southern blot with LMP-1 probe, indicating that the 3 had already been positive for EBV before subcloning. YT-O expressed limited amount of EBNA2 or LMP-1 mRNA, whereas the 2 subclones expressed abundant EBNA2 or LMP-1 mRNA in the Northern blot analysis with EBNA2 or LMP-1 probe. Thus, the ex vivo cells were positive for EBV, since the BL (Burkitt lymphoma) type EBV gene expression in the YT-O does not generally occur in in vitro infection. The remaining clinical record indicated that the lymphoma was extranodal (angiocentric lymphoma), involving mediastinum and liver, but not nodal or lymphoblastic lymphoma (LBL). Acute lymphoblastic lymphoma (ALL)/LBL of the NK-lineage has not been defined, although such neoplasms should exist. Since T- and NK-lineages are so close in immature stages of differentiation that ALL/LBL of NK may have been sorted into T-lineage. The phenotypic records of the T-ALL/LBL in our laboratory indicated that CD7+CD5+CD2- is much higher in incidence than CD7+CD5-CD2+. This may reflect the size difference of physiological populations of T- and NK-lineage cells. Furthermore, the latter is of CD45RO type in contrast to the rest of the early-thymic (pro-thymic) T-ALL/LBL groups of CD45RA type. A CD56+ case of 4 CD7+CD5-CD2+ cases have been published as a case of LBL of NK-lineage. It is necessary to scrutinize CD7+CD5-CD2+ cells in order to clarify the phenotype of neoplastic and physiological NK cells in immature stages.     

Analysis of Epstein-Barr virus (EBV) type and variant in spontaneous lymphoblastoid cells and Hu-SCID mouse tumours

Epstein-Barr virus (EBV) type and strain variations were examined using both lymphoblastoid cell lines (LCLs), spontaneously derived in vitro from peripheral blood mononuclear cells (PBMC) of 15 HIV-1-seropositive individuals; and SCID mouse tumours induced by inoculation of PBMC from 11 healthy human donors (Hu-SCID tumours). Polymerase chain reaction (PCR) analysis disclosed that all but one of the 26 EBV + samples harboured EBV nuclear antigen (EBNA) 2 and 3C type A virus. On the other hand, single strand conformation polymorphism (SSCP) analysis using Epstein-Barr encoded RNA (EBER) specific primers detected an AG876-like (type B) band pattern in 21 of the 26 EBV + samples. Three Hu-SCID tumours scored as B95.8-like (type A), and two showed neither a type A nor a type B SSCP migration pattern. Sequence analysis of the amplified EBER fragments confirmed the PCR-SSCP findings; moreover, additional mutations were present not only in the two EBV + samples with anomalous SSCP pattern, but also in two other samples with a standard SSCP profile. Thus, EBER analysis did not correlate with EBNA typing, and appeared to be unsuitable for EBV type assessment. Latent membrane protein (LMP) analysis disclosed, on the whole, sever size variants: as expected, the differences were due to the variable numbers of a 33-bp repeat in the amplified fragment, as assessed by direct sequencing. The broader variability detected by LMP analysis should prove more useful than typing for assessing the presence of single and/or mixed variants resulting from EBV reactivation and/or reinfection.