Preferential association of hepatitis C virus with CD19+ B cells is mediated by complement system

Extrahepatic disease manifestations are common in chronic hepatitis C virus (HCV) infection. The mechanism of HCV-related lymphoproliferative disorders is not fully understood. Recent studies have found that HCV in peripheral blood mononuclear cells (PBMCs) from chronically infected patients is mainly associated with CD19+ B cells. To further elucidate this preferential association of HCV with B cells, we used in vitro cultured virus and uninfected PBMCs from healthy blood donors to investigate the necessary serum components that activate the binding of HCV to B cells. First, we found that the active serum components were present not only in HCV carriers, but also in HCV recovered patients and HCV negative healthy blood donors and that the serum components were heat labile. Second, the preferential binding activity of HCV to B cells could be blocked by anti-complement C3 antibodies. In experiments with complement-depleted serum and purified complement proteins, we demonstrated that complement proteins C1, C2, and C3 were required to activate such binding activity. Complement protein C4 was partially involved in this process. Third, using antibodies against cell surface markers, we showed that the binding complex mainly involved CD21 (complement receptor 2), CD19, CD20, and CD81; CD35 (complement receptor 1) was involved but had lower binding activity. Fourth, both anti-CD21 and anti-CD35 antibodies could block the binding of patient-derived HCV to B cells. Fifth, complement also mediated HCV binding to Raji cells, a cultured B cell line derived from Burkitt´s lymphoma.CONCLUSION:In chronic HCV infection, the preferential association of HCV with B cells is mediated by the complement system, mainly through complement receptor 2 (CD21), in conjunction with the CD19 and CD81 complex. This article is protected by copyright. All rights reserved.Fil: Wang, Richard. National Institutes of Health; Estados UnidosFil: Baré, Patricia. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; Argentina. National Institutes of Health; Estados UnidosFil: De Giorgi, Valeria. National Institutes of Health; Estados UnidosFil: Matsuura, Kentaro. Nagoya City University Graduate School of Medicine; Japón. National Institutes of Health; Estados UnidosFil: Salam, Kazi Abdus. National Institutes of Health; Estados Unidos. University of Rajshahi; IndiaFil: Grandinetti, Teresa. National Institutes of Health; Estados UnidosFil: Schechterly, Cathy. National Institutes of Health; Estados UnidosFil: Alter, Harvey J.. National Institutes of Health; Estados Unido

Highly quantitative serological detection of anti-cytomegalovirus (CMV) antibodies

<p>Abstract</p> <p>Background</p> <p>Human cytomegalovirus infection is associated with a variety of pathological conditions including retinitis, pneumonia, hepatitis and encephalitis that may be transmitted congenitally, horizontally and parenterally and occurs both as a primary infection and as reactivation in immunocompromised individuals. Currently, there is a need for improved quantitative serological tests to document seropositivity with high sensitivity and specificity.</p> <p>Methods</p> <p>Here we investigated whether luciferase immunoprecipitation systems (LIPS) would provide a more quantitative and sensitive method for detecting anti-CMV antibodies. Four protein fragments of immunodominant regions of CMV antigens pp150 and pp65 were generated as <it>Renilla </it>luciferase (Ruc) fusion proteins and used in LIPS with two cohorts of CMV positive and negative sera samples previously tested by ELISA.</p> <p>Results</p> <p>Analysis of the antibody responses to two of these antigen fragments, pp150-d1 and pp150-d2, revealed geometric mean antibody titers in the first cohort that were 100–1000 fold higher in the CMV positive sera compared to the CMV negative samples (p < 0.0001) and infection status exactly matched the ELISA results for the 46 samples of the first cohort (100% sensitivity and 100% specificity). Two additional antigen fragments, pp65-d1 and pp65-d2 also showed robust antibody titers in some CMV-infected sera and yielded 50% and 96% sensitivity, respectively. Analysis of a second cohort of 70 samples using a mixture of the 4 antigens, which simplifies data collection and analysis, yielded values which correlated well with the sum of the values from the 4 separate tests (<it>r</it>_{<it>s </it>}= 0.93, p < 0.00001). While comparison of the LIPS results from this second cohort with ELISA showed 100% sensitivity, LIPS detected six additional CMV positive samples that were not detected by ELISA. Heat map analysis revealed that several of the LIPS positive/ELISA negative samples had positive LIPS immunoreactivity with 3–4 of the CMV antigens.</p> <p>Conclusion</p> <p>These results suggest that LIPS provides a highly robust and quantitative method for studying anti-CMV antibodies and has the potential to more accurately document CMV infection than standard ELISA.</p

An assessment of hepatitis E virus (HEV) in US blood donors and recipients: No detectable HEV RNA in 1939 donors tested and no evidence for HEV transmission to 362 prospectively followed recipients.

BACKGROUND: Hepatitis E virus (HEV) infection has become relevant to blood transfusion practice because isolated cases of blood transmission have been reported and because HEV has been found to cause chronic infection and severe liver disease in immunocompromised patients. STUDY DESIGN AND METHODS: We tested for immunoglobulin (Ig)G and IgM antibodies to the HEV and for HEV RNA in 1939 unselected volunteer US blood donors. Subsequently, we tested the same variables in pre- and serial posttransfusion samples from 362 prospectively followed blood recipients to assess transfusion risk. RESULTS: IgG anti-HEV seroprevalence in the total 1939 donations was 18.8%: 916 of these donations were made in 2006 at which time the seroprevalence was 21.8% and the remaining 1023 donations were in 2012 when the seroprevalence had decreased to 16.0% (p \u3c 0.01). A significant (p \u3c 0.001) stepwise increase in anti-HEV seroprevalence was seen with increasing age. Eight of 1939 donations (0.4%) tested anti-HEV IgM positive; no donation was HEV RNA positive. Two recipients had an apparent anti-HEV seroconversion, but temporal relationships and linked donor testing showed that these were not transfusion-transmitted HEV infections. CONCLUSION: No transfusion-transmitted HEV infections were observed in 362 prospectively followed blood recipients despite an anti-HEV seroprevalence among donations exceeding 16%

Differential responses of plasmacytoid dendritic cells to influenza virus and distinct viral pathogens.

Plasmacytoid dendritic cells (pDCs) are key components of the innate immune response that are capable of synthesizing and rapidly releasing vast amounts of type I interferons (IFNs), particularly IFN-α. Here we investigated whether pDCs, often regarded as a mere source of IFN, discriminate between various functionally discrete stimuli and to what extent this reflects differences in pDC responses other than IFN-α release. To examine the ability of pDCs to differentially respond to various doses of intact and infectious HIV, hepatitis C virus, and H1N1 influenza virus, whole-genome gene expression analysis, enzyme-linked immunosorbent assays, and flow cytometry were used to investigate pDC responses at the transcriptional, protein, and cellular levels. Our data demonstrate that pDCs respond differentially to various viral stimuli with significant changes in gene expression, including those involved in pDC activation, migration, viral endocytosis, survival, or apoptosis. In some cases, the expression of these genes was induced even at levels comparable to that of IFN-α. Interestingly, we also found that depending on the viral entity and the viral titer used for stimulation, induction of IFN-α gene expression and the actual release of IFN-α are not necessarily temporally coordinated. In addition, our data suggest that high-titer influenza A (H1N1) virus infection can stimulate rapid pDC apoptosis. IMPORTANCE Plasmacytoid dendritic cells (pDCs) are key players in the viral immune response. With the host response to viral infection being dependent on specific virus characteristics, a thorough examination and comparison of pDC responses to various viruses at various titers is beneficial for the field of virology. Our study illustrates that pDC infection with influenza virus, HIV, or hepatitis C virus results in a unique and differential response to each virus. These results have implications for future virology research, vaccine development, and virology as a whole

Natural Variation in Fc Glycosylation of HIV-Specific Antibodies Impacts Antiviral Activity

While the induction of a neutralizing antibody response against HIV remains a daunting goal, data from both natural infection and vaccine-induced immune responses suggest that it may be possible to induce antibodies with enhanced Fc effector activity and improved antiviral control via vaccination. However, the specific features of naturally induced HIV-specific antibodies that allow for the potent recruitment of antiviral activity and the means by which these functions are regulated are poorly defined. Because antibody effector functions are critically dependent on antibody Fc domain glycosylation, we aimed to define the natural glycoforms associated with robust Fc-mediated antiviral activity. We demonstrate that spontaneous control of HIV and improved antiviral activity are associated with a dramatic shift in the global antibody-glycosylation profile toward agalactosylated glycoforms. HIV-specific antibodies exhibited an even greater frequency of agalactosylated, afucosylated, and asialylated glycans. These glycoforms were associated with enhanced Fc-mediated reduction of viral replication and enhanced Fc receptor binding and were consistent with transcriptional profiling of glycosyltransferases in peripheral B cells. These data suggest that B cell programs tune antibody glycosylation actively in an antigen-specific manner, potentially contributing to antiviral control during HIV infection

Biologic Phenotyping of the Human Small Airway Epithelial Response to Cigarette Smoking

BACKGROUND: The first changes associated with smoking are in the small airway epithelium (SAE). Given that smoking alters SAE gene expression, but only a fraction of smokers develop chronic obstructive pulmonary disease (COPD), we hypothesized that assessment of SAE genome-wide gene expression would permit biologic phenotyping of the smoking response, and that a subset of healthy smokers would have a "COPD-like" SAE transcriptome. METHODOLOGY/PRINCIPAL FINDINGS: SAE (10th-12th generation) was obtained via bronchoscopy of healthy nonsmokers, healthy smokers and COPD smokers and microarray analysis was used to identify differentially expressed genes. Individual responsiveness to smoking was quantified with an index representing the % of smoking-responsive genes abnormally expressed (I(SAE)), with healthy smokers grouped into "high" and "low" responders based on the proportion of smoking-responsive genes up- or down-regulated in each smoker. Smokers demonstrated significant variability in SAE transcriptome with I(SAE) ranging from 2.9 to 51.5%. While the SAE transcriptome of "low" responder healthy smokers differed from both "high" responders and smokers with COPD, the transcriptome of the "high" responder healthy smokers was indistinguishable from COPD smokers. CONCLUSION/SIGNIFICANCE: The SAE transcriptome can be used to classify clinically healthy smokers into subgroups with lesser and greater responses to cigarette smoking, even though these subgroups are indistinguishable by clinical criteria. This identifies a group of smokers with a "COPD-like" SAE transcriptome

Governing the Global Land Grab: Multipolarity, Ideas and Complexity in Transnational Governance

Since 2008, a series of new regulatory initiatives have emerged to address large-scale land grabs. These initiatives are occurring simultaneously at multiple levels of social organization instead of a single, overarching institutional site. A significant portion of this activity is taking place at the transnational level. We suggest that transnational land governance is indicative of emerging shifts in the practice of governance of global affairs. We analyze such shifts by asking two related questions: what does land grabbing tell us about developments in transnational governance, particularly with regard to North-South relations, and what do these developments in transnational governance mean for regulating land grabbing?Desde 2008, ha surgido una serie de nuevas iniciativas regulatorias para tratar acaparamientos de tierra a gran escala. Estas iniciativas est&aacute;n sucediendo simult&aacute;neamente a niveles m&uacute;ltiples de la organizaci&oacute;n social en vez de un lugar institucional predominante. Una porci&oacute;n importante de esta actividad est&aacute; tomando lugar al nivel transnacional. Sugerimos que la gobernanza de tierras trasnacionales es indicativa de los cambios que est&aacute;n surgiendo en la pr&aacute;ctica de gobernanza de los asuntos globales. Analizamos tales cambios haciendo dos preguntas relacionadas: &iquest;qu&eacute; nos dice el acaparamiento de tierras sobre los desarrollos en la gobernanza trasnacional, particularmente con las relaciones norte-sur?, y &iquest;qu&eacute; significan estos desarrollos en gobernanza trasnacional para regular el acaparamiento de tierras