Lack of evidence of active lytic replication of Epstein-Barr and cytomegaloviruses in patients with systemic lupus erythematosus

Objectives Systemic lupus erythematosus (SLE) is a multifactorial disease. Environmental factors such as viral infection(s) have been proposed as pathaetiological factors. There are particular interests in studying lymphotropic viruses such as the Epstein-Barr virus (EBV) and cytomegalovirus (CMV). Although previous case reports and in vitro studies suggested that they may have a role, there is no direct evidence that onset of SLE or disease exacerbation is associated with active infection by these viruses. Using the very sensitive polymerase chain reaction (PCR) technique, we tried to find out evidence of active replication of these viruses in patients with SLE. Methods Thirty-four patients with SLE were compared with matched normal controls. Eleven patients were newly diagnosed to have SLE and 18 of the 34 patients had active disease as determined by a SLE Disease Activity Index (SLEDAI) score of ≥10 at the time of study. Results Our results showed no evidence of active replication or reactivation of EBV in the leucocytes amongst the newly diagnosed SLE patients, established SLE patients, patients with SLEDAI ≥10, patients with SLEDAI <10, and control subjects. There was no evidence of CMV infection in any of the subjects studied. The IgG and IgA responses against EBV early antigen (EA) and viral capsid antigen (VCA) were also studied. The IgG and IgA responses against VCA of EBV were increased in patients with SLE when compared with controls. However, there were no differences in these responses among different subgroups of patients. The mechanism of these responses was not apparent but may represent non-specific hyperimmune responses in these patients. There were no differences in the titre of IgG and IgA against EBV EA between the patient groups and controls.Conclusion There is no direct evidence that either EBV or CMV plays a direct role in the onset and/or exacerbation of SLE.

Reactivation of Latent Infection of Human Herpesvirus 8 in BC-3 Cells from Primary Effusion Lymphoma by Recombinant CytokinesSimilar to that Produced by HIV-1-infected T Cells

Objective: To study and confirm that recombinant cytokines similar to those produced by HIV-1 infected T cells induced lytic cycle replication of human herpesvirus 8 (HHV-8) in BC-3 cells, another cell line from primary effusion lymphama(PEL). Methods: The persistent stimulation of BC-3 was conducted by several cytokines known to be produced by HIV-1-infected T cells and important in growth and proliferation of Kaposi's sarcoma(KS)cells in vitro, such as the interferon-γ (IFN-γ) , tlie hepatocyte growth factor/scatter factor (HGF / SF) , the Oncostain M(OSM) , and the tumor necrosis factor-α (TNF-α)which is not produced by HIV-1-infected T cells. Treated and untreated BC-3 cells were collected at the 3rd and 7th day of persistent stimulation, respectively. Immuno-histochemical (IHC) staining, Northern blot, quantitative PCR (real- time PCR ) and electron microscopy (EM) were carried out to detect the expression of immunogenic protein ORF59, messenger RNA (mRNA) of minor capsid protein ORF26, and the presence of viral particles of HHV-8 from treated and untreated BC-3 cells. Results: It showed that IFN-γ, HGF/SF, OSM, and TNF-α were found to induce an increase in mRNA expression of ORF26 when added individually to BC-3 cells. Particularly, ORF26 expression stimulated with IFN-γ and TNF-α respectively, increased 6. 1 and 2. 5-fold(from real-time PCR results)at the 7th day when compared with untreated BC-3 cells. Meanwhile, about 20% of IFN-γ stimulated BC-3 cells expressed ORF59 at the 7th day as compared with 1. 5% of untreated BC-3 cells when IHC staining was employed. In addition, viral particles of HHV-8 were readily identified in BC-3 cells stimulated with IFN-γ at the 7th day with EM analysis. Conclusion;TNF-α and recombinant cytokines being similar to those produced by HIV- 1 infected T Cells could really induce HHV- 8 lytic cycle replication in BC-3 cells, another cell line of PEL.

CCAAT/enhancer binding proteins play a role in oriLyt-dependent genome replication during MHV-68 de novo infection

Murine gammaherpesvirus 68(MHV-68),a member of the gammaherpesvirus family,replicates robustly in permissive cell lines and is able to infect laboratory mice.MHV-68 has emerged as a model for studying the basic aspects of viral replication and host–virus interactions of its human counterparts.Herpesvirus genome replication is mediated through a cis-element in the viral genome called the origin of lytic replication(oriLyt).A family of transcription factors,CCAAT/enhancer binding proteins(C/EBPs),assists in oriLyt-mediated DNA replication during gammaherpesvirus reactivation.In this study,we examined the role of C/EBPs in gammaherpesvirus DNA replication during de novo infection,using MHV-68 as a model.We found that C/EBP α and β bind to the CCAAT boxes in the MHV-68 oriLyt core region both in vitro and in vivo,as demonstrated by electrophoretic mobility shift assay and chromatin immunoprecipitation assay.A dominant negative form of C/EBPs significantly impaired the lytic replication efficiency of MHV-68 on both the plasmid and genome levels in a replication assay,indicating that functional C/EBPs are required for maximal MHV-68 genome DNA replication.Collectively,our data demonstrate that C/EBPs interact with the oriLyt core region and play an important role in MHV-68 lytic DNA replication during de novo infection.