22 research outputs found
No Evidence for XMRV Nucleic Acids, Infectious Virus or Anti-XMRV Antibodies in Canadian Patients with Chronic Fatigue Syndrome
The gammaretroviruses xenotropic murine leukemia virus (MLV)-related virus (XMRV) and MLV have been reported to be more prevalent in plasma and peripheral blood mononuclear cells of chronic fatigue syndrome (CFS) patients than in healthy controls. Here, we report the complex analysis of whole blood and plasma samples from 58 CFS patients and 57 controls from Canada for the presence of XMRV/MLV nucleic acids, infectious virus, and XMRV/MLV-specific antibodies. Multiple techniques were employed, including nested and qRT-PCR, cell culture, and immunoblotting. We found no evidence of XMRV or MLV in humans and conclude that CFS is not associated with these gammaretroviruses
Functional and immunogenic characterization of diverse HCV glycoprotein E2 variants
© 2018 European Association for the Study of the Liver Background & Aims: Induction of cross-reactive antibodies targeting conserved epitopes of the envelope proteins E1E2 is a key requirement for an hepatitis C virus vaccine. Conserved epitopes like the viral CD81-binding site are targeted by rare broadly neutralizing antibodies. However, these viral segments are occluded by variable regions and glycans. We aimed to identify antigens exposing conserved epitopes and to characterize their immunogenicity. Methods: We created hepatitis C virus variants with mutated glycosylation sites and/or hypervariable region 1 (HVR1). Exposure of the CD81 binding site and conserved epitopes was quantified by soluble CD81 and antibody interaction and neutralization assays. E2 or E1-E2 heterodimers with mutations causing epitope exposure were used to immunize mice. Vaccine-induced antibodies were examined and compared with patient-derived antibodies. Results: Mutant viruses bound soluble CD81 and antibodies targeting the CD81 binding site with enhanced efficacy. Mice immunized with E2 or E1E2 heterodimers incorporating these modifications mounted strong, cross-binding, and non-interfering antibodies. E2-induced antibodies neutralized the autologous virus but they were not cross-neutralizing. Conclusions: Viruses lacking the HVR1 and selected glycosylation sites expose the CD81 binding site and cross-neutralization antibody epitopes. Recombinant E2 proteins carrying these modifications induce strong cross-binding but not cross-neutralizing antibodies. Lay summary: Conserved viral epitopes can be made considerably more accessible for binding of potently neutralizing antibodies by deletion of hypervariable region 1 and selected glycosylation sites. Recombinant E2 proteins carrying these mutations are unable to elicit cross-neutralizing antibodies suggesting that exposure of conserved epitopes is not sufficient to focus antibody responses on production of cross-neutralizing antibodies
Humanizing sociotechnical transitions through energy justice: an ethical framework for global transformative change
Poverty, climate change and energy security demand awareness about the interlinkages between energy systems and social justice. Amidst these challenges, energy justice has emerged to conceptualize a world where all individuals, across all areas, have safe, affordable and sustainable energy that is, essentially, socially just. Simultaneously, new social and technological solutions to energy problems continually evolve, and interest in the concept of sociotechnical transitions has grown. However, an element often missing from such transitions frameworks is explicit engagement with energy justice frameworks. Despite the development of an embryonic set of literature around these themes, an obvious research gap has emerged: can energy justice and transitions frameworks be combined? This paper argues that they can. It does so through an exploration of the multi-level perspective on sociotechnical systems and an integration of energy justice at the model’s niche, regime and landscape level. It presents the argument that it is within the overarching process of sociotechnical change that issues of energy justice emerge. Here, inattention to social justice issues can cause injustices, whereas attention to them can provide a means to examine and potential resolve them
Enhanced activation of memory, but not naive, B cells in chronic hepatitis C virus-infected patients with cryoglobulinemia and advanced liver fibrosis.
Mixed cryoglobulinemia is the most common extrahepatic disease manifestation of chronic hepatitis C virus (HCV) infection, where immunoglobulins precipitate at low temperatures and cause symptoms such as vasculitis, glomerulonephritis and arthralgia. HCV-associated cryoglobulinemia is also strongly linked with the development of B cell non-Hodgkin lymphoma. Abnormal B cell function in HCV infections can lead to the formation of HCV cryoglobulin complexes that usually comprise monoclonal rheumatoid factor and HCV-specific immune complexes. The aim of this study was to characterize the activation phenotype of B cells from patients with chronic HCV infection in comparison to healthy controls using flow cytometry. In addition, we determined how the activation status varies depending on the presence of cryoglobulinemia and advanced liver fibrosis. We found that only memory B cells, not naïve cells, were significantly activated in chronic HCV infection when compared with healthy controls. We also identified markers of memory B cell activation that were specific for HCV patients with cryoglobulinemia (CD86, CD71, HLA-DR) and advanced liver disease (CD86). Our results demonstrate that HCV infection has differential effects on B cells depending on the severity of hepatic and extrahepatic disease
Gating strategy for flow cytometry analysis of memory and naïve B cell activation.
<p>Lymphocytes were gated by FSC/SSC properties and memory B cells (CD19+CD27+) and naïve B cells (CD19+CD27−) were analyzed within the lymphocyte gate for the expression of 6 different markers described in the Materials and Methods. Histograms show a representative example of the expression of CD183 (numbers represent geometric mean fluorescent intensity) on memory and naïve B cells from a healthy control (HCV-) and chronic HCV patient (HCV+).</p
PBMC and B cell quantification and clinical characteristics of cryoglobulin positive versus cryoglobulin negative HCV patients.
<p>(<b>A–B</b>) PBMCs were freshly isolated and analyzed by flow cytometry as in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0068308#pone-0068308-g002" target="_blank">Figure 2</a> except that this analysis compares cryoglobulin+ (n = 20, cryo+) and cryoglobulin- (n = 34, cryo-) HCV patients. (<b>A</b>) The total percent of CD19+ B cells within the lymphocyte gate and number of B cells per ml of blood based on our isolations. (<b>B</b>) The percent of memory (CD19+CD27+) and naïve (CD19+CD27−) and number of each subset per ml of blood. (<b>C</b>) The number of total PBMCs isolated per ml of blood. (<b>D</b>) The alanine aminotransferase (ALT) and gamma-glutamyl transpeptidase (GGT) levels were measured in the serum in units/L (U/L) for 54 (ALT) or 48 (GGT) HCV patients. (<b>E</b>) Serum HCV RNA titers were quantified by qRT-PCR as described in the Materials and Methods for all 54 HCV patients. Horizontal lines on graphs represent mean +/− SEM (A-B, percentages, C) or median (A–B numbers, D, E) values. *, P<0.05, n.s., not significant. IU/ml, international units/ml.</p
B cell subset frequencies are unchanged in HCV patients compared to controls.
<p>(<b>A–C</b>) 7.5×10<sup>5</sup> freshly isolated PBMCs from chronically infected HCV patients (n = 54) or healthy controls (n = 50) were incubated with fluorescently labeled antibodies to CD19, CD27 and CD5 for multi-color flow cytometry analysis. (<b>A</b>) The total percent of CD19+ B cells within the lymphocyte gate and number of B cells per ml of blood based on our isolations. (<b>B</b>) The percent of memory (CD19+CD27+) and naïve (CD19+CD27−) and number of each subset per ml of blood. <b>(C)</b> The percent and number per ml of CD5+CD19+ B cells. Horizontal lines on graphs represent means +/− SEM (percentages) or median (number of cells/ml) values. In (C) only 48 HCV and 47 healthy control samples were tested for CD5. *, P<0.05; n.s., not significant.</p
HCV patients with advanced fibrosis have increased expression of CD86 on memory B cells.
<p>Fibrosis scores were determined as outlined in the Materials and Methods, where scores of 3–4 are considered advanced fibrosis/cirrhosis (F4). PBMCs were freshly isolated and analyzed by flow cytometry as in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0068308#pone-0068308-g003" target="_blank">Figure 3</a>. The expression level and percent positive of cells expressing CD86 (geometric mean fluorescent intensity (MFI) or percent positive compared to mouse isotype controls) were calculated for memory (CD19+CD27+) and naïve (CD19+CD27−) B cells. Horizontal lines represent median values. *, P<0.05; n.s., not significant.</p