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Aarthi Sundararajan,
Lifang Huan,
Katherine A Richards,
Glendie Marcelin,
Shabnam Alam,
Hyemee Joo,
Hongmei Yang,
Richard J Webby,
David J Topham,
Andrea J Sant, Mark Y Sangster
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ABSTRACT: The antibody response to influenza infection is largely dependent on CD4 T cell help for B cells. Cognate signals and secreted factors provided by CD4 T cells drive B cell activation and regulate antibody isotype switching for optimal antiviral activity. Recently, we analyzed HLA-DR1 transgenic (DR1) mice and C57BL/10 (B10) mice after infection with influenza virus A/New Caledonia/20/99 (NC) and defined epitopes recognized by virus-specific CD4 T cells. Using this information in the current study, we demonstrate that the pattern of secretion of IL-2, IFN-γ, and IL-4 by CD4 T cells activated by NC infection is largely independent of epitope specificity and the magnitude of the epitope-specific response. Interestingly, however, the characteristics of the virus-specific CD4 T cell and the B cell response to NC infection differed in DR1 and B10 mice. The response in B10 mice featured predominantly IFN-γ-secreting CD4 T cells and strong IgG2b/IgG2c production. In contrast, in DR1 mice most CD4 T cells secreted IL-2 and IgG production was IgG1-biased. Infection of DR1 mice with influenza PR8 generated a response that was comparable to that in B10 mice, with predominantly IFN-γ-secreting CD4 T cells and greater numbers of IgG2c than IgG1 antibody-secreting cells. The response to intramuscular vaccination with inactivated NC was similar in DR1 and B10 mice; the majority of CD4 T cells secreted IL-2 and most IgG antibody-secreting cells produced IgG2b or IgG2c. Our findings identify inherent host influences on characteristics of the virus-specific CD4 T cell and B cell responses that are restricted to the lung environment. Furthermore, we show that these host influences are substantially modulated by the type of infecting virus via the early induction of innate factors. Our findings emphasize the importance of immunization strategy for demonstrating inherent host differences in CD4 T cell and B cell responses.
PLoS ONE 01/2012; 7(3):e34377. · 4.09 Impact Factor
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ABSTRACT: Reactions to pathogens are usually tuned to effect immunity and limit tissue damage. Several host counterinflammatory mechanisms inhibit tissue damage but these may also act to constrain the effectiveness of immunity to acute infections, as we demonstrate in mice acutely infected with influenza A virus (IAV). We show that compared with wild type (WT), galectin-9 knockout (G9KO) mice mounted a more robust acute phase virus-specific CD8 T-cell response as well as higher and more rapid virus-specific serum IgM, IgG, and IgA responses and also cleared virus more rapidly than did WT mice. Blocking galectin-9 signals to Tim-3-expressing cells using a Tim-3 fusion protein resulted in improved immune responses in WT mice. When IAV immune mice were challenged with a heterologous IAV, the secondary IAV-specific CD8 T-cell responses were four- to fivefold higher in G9KO compared with WT mice. Our results indicate that manipulating galectin signals may represent a convenient approach to improve immune responses to some vaccines.
Proceedings of the National Academy of Sciences 11/2011; 108(47):19001-6. · 9.68 Impact Factor
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ABSTRACT: Pomegranate juice (PJ) and pomegranate polyphenolic extracts (PP) have antiviral effects against HIV-1, influenza, herpes, and poxviruses, and we recently demonstrated their effect against human noroviral surrogates. In the present study, the time-dependent effects of two commercial brands of PJ and PP at two concentrations (2 and 4 mg/mL) on the infectivity of foodborne viral surrogates (feline calicivirus FCV-F9, murine norovirus MNV-1, and MS2 bacteriophage) at room temperature for up to 1 h were evaluated. Each virus at ∼5 log(10) plaque-forming units (PFU)/mL was mixed with equal volumes of PJ, or PP at 4 or 8 mg/mL, and incubated for 0, 10, 20, 30, 45, and 60 min at room temperature. Viral titers after each treatment were determined by standardized plaque assays and compared with untreated controls. Virus titer reduction by PJ and PP was found to be a rather rapid process, with ≥50% of titer reduction occurring within the first 20 min of treatment for all three tested viruses. Within the first 20 min, titer reductions of 3.12, 0.79, and 0.23 log(10) PFU/mL for FCV-F9, MNV-1, and MS2, respectively, were obtained using PJ. FCV-F9, MNV-1, and MS2 titers were reduced by 4.02, 0.68, and 0.18 log(10) PFU/mL with 2 mg/mL PP and 5.09, 1.14, and 0.19 log(10) PFU/mL with 4 mg/mL PP, respectively, after 20 min. The mechanism of viral reduction by PJ and PP needs to be elucidated and clinical trials should be undertaken before recommending for therapeutic or preventive purposes.
Foodborne Pathogens and Disease 07/2011; 8(11):1177-83. · 2.26 Impact Factor
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ABSTRACT: Pomegranate juice (PJ) has gained popularity because of its associated antioxidant, antimicrobial, anticancer, and anti-inflammatory properties. However, its effects against epidemiologically significant foodborne viruses have not been investigated. In the absence of culturable human noroviruses, feline calicivirus (FCV-F9), murine norovirus (MNV-1), and MS2 (ssRNA) bacteriophage were used as foodborne viral surrogates. The aim of this research was to study the effects of PJ and pomegranate polyphenols (PP) on foodborne viral infectivity. Viruses at high (∼ 7 log(10) PFU/mL) or low (∼ 5 log(10) PFU/mL) titers were mixed with equal volumes of PJ, 8, 16, and 32 mg/mL of PP, or water (control) and incubated for 1 h at room temperature. Viral infectivity after treatments was evaluated using standardized plaque assays. PJ decreased the titer of FCV-F9, MNV-1, and MS2 by 2.56, 1.32, and 0.32 log(10) PFU/mL, respectively, for low titers and 1.20, 0.06, and 0.63 log(10) PFU/mL, respectively, for high titers. Interestingly, FCV-F9 was undetectable after exposure to the three tested PP solutions using both low and high titers. MNV-1 at low initial titers was reduced by 1.30, 2.11, and 3.61 log(10) PFU/mL and at high initial titers by 1.56, 1.48, and 1.54 log(10) PFU/mL with 4, 8, and 16 mg/mL of PP treatment, respectively. MS2 at low initial titers was reduced by 0.41, 0.45, and 0.93 log(10) PFU/mL and at high initial titers by 0.32, 0.41, and 0.72 log(10) PFU/mL after 4, 8, and 16 mg/mL of PP treatment, respectively. PJ and PP resulted in titer reductions of foodborne virus surrogates after 1 h exposure, showing promise for use in hurdle technologies and/or for therapeutic or preventive use. To suggest the use of PJ and PP as natural remedies for foodborne viral illness prevention, their mechanism of action against viral infectivity needs to be further investigated.
Foodborne Pathogens and Disease 12/2010; 7(12):1473-9. · 2.26 Impact Factor
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ABSTRACT: Pomegranates have high levels of polyphenols (PPs) and may be a rich source of compounds with antiviral activity. We evaluated the direct anti-influenza activity of three commercially available pomegranate extracts: pomegranate juice (PJ), a concentrated liquid extract (POMxl), and a 93% PP powder extract (POMxp). The acidity of PJ and POMxl solutions contributed to rapid anti-influenza activity, but this was not a factor with POMxp. Studies using POMxp showed that 5min treatment at room temperature with 800μg/ml PPs resulted in at least a 3log reduction in the titers of influenza viruses PR8 (H1N1), X31 (H3N2), and a reassortant H5N1 virus derived from a human isolate. However, the antiviral activity was less against a coronavirus and reassortant H5N1 influenza viruses derived from avian isolates. The loss of influenza infectivity was frequently accompanied by loss of hemagglutinating activity. PP treatment decreased Ab binding to viral surface molecules, suggesting some coating of particles, but this did not always correlate with loss of infectivity. Electron microscopic analysis indicated that viral inactivation by PPs was primarily a consequence of virion structural damage. Our findings demonstrate that the direct anti-influenza activity of pomegranate PPs is substantially modulated by small changes in envelope glycoproteins.
Antiviral research 10/2010; 88(1):1-9. · 3.61 Impact Factor
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ABSTRACT: We consider both Ab-secreting cell (ASC) and memory B cell (B(Mem)) populations in a quantitative analysis of virus-specific B cell memory generated by intramuscular or intranasal vaccination of mice with inactivated influenza virus. After both forms of vaccination, the memory phase was characterized by localization of ASCs in the bone marrow and dispersion of B(Mem) to organized lymphoid tissues. The stronger IgG response to intramuscular vaccination correlated with larger numbers of IgG ASCs in the bone marrow and IgG B(Mem). IgA production was only prominent in the response to intranasal vaccination and was associated with IgA ASC localization in the lung and IgA B(Mem) formation. Notably, few IgG ASCs or B(Mem) localized in the lung after intramuscular vaccination, in contrast to the situation following influenza pneumonia. Our analysis links the nature of immunization to characteristics of the state of B cell memory that may relate to protective immunity.
Vaccine 03/2010; 28(10):2186-94. · 3.77 Impact Factor
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Zhaoyang Li,
Hongsheng Wang,
Liquan Xue,
Dong-Mi Shin,
Derry Roopenian,
Wu Xu,
Chen-Feng Qi, Mark Y Sangster,
Carlos J Orihuela,
Elaine Tuomanen,
Jerold E Rehg,
Xiaoli Cui,
Quangeng Zhang,
Herbert C Morse,
Stephan W Morris
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ABSTRACT: BCL10, required for nuclear factor kappaB (NF-kappaB) activation during antigen-driven lymphocyte responses, is aberrantly expressed in mucosa-associated lymphoid tissue-type marginal zone (MZ) lymphomas because of chromosomal translocations. Emu-driven human BCL10 transgenic (Tg) mice, which we created and characterize here, had expanded populations of MZ B cells and reduced follicular and B1a cells. Splenic B cells from Tg mice exhibited constitutive activation of both canonical and noncanonical NF-kappaB signaling pathways is associated with increased expression of NF-kappaB target genes. These genes included Tnfsf13b, which encodes the B-cell activating factor (BAFF). In addition, levels of BAFF were significantly increased in sera from Tg mice. MZ B cells of Tg mice exhibited reduced turnover in vivo and enhanced survival in vitro, indicative of lymphoaccumulation rather than lymphoproliferation as the cause of MZ expansion. In vivo antibody responses to both T-independent, and especially T-dependent, antigens were significantly reduced in Tg mice. Mortality was accelerated in Tg animals, and some mice older than 8 months had histologic and molecular findings indicative of clonal splenic MZ lymphoma. These results suggest that, in addition to constitutive activation of BCL10 in MZ B cells, other genetic factors or environmental influences are required for short latency oncogenic transformation.
Blood 09/2009; 114(19):4158-68. · 9.90 Impact Factor
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ABSTRACT: Posttranslational modification of proteins, such as glycosylation, can impact cell signaling and function. ST6Gal I, a glycosyltransferase expressed by B cells, catalyzes the addition of alpha-2,6 sialic acid to galactose, a modification found on N-linked glycoproteins such as CD22, a negative regulator of B cell activation. We show that SNA lectin, which binds alpha-2,6 sialic acid linked to galactose, shows high binding on plasma blasts and germinal center B cells following viral infection, suggesting ST6Gal I expression remains high on activated B cells in vivo. To understand the relevance of this modification on the antiviral B cell immune response, we infected ST6Gal I(-/-) mice with influenza A/HKx31. We demonstrate that the loss of ST6Gal I expression results in similar influenza infectivity in the lung, but significantly reduced early influenza-specific IgM and IgG levels in the serum, as well as significantly reduced numbers of early viral-specific Ab-secreting cells. At later memory time points, ST6Gal I(-/-) mice show comparable numbers of IgG influenza-specific memory B cells and long-lived plasma cells, with similarly high antiviral IgG titers, with the exception of IgG2c. Finally, we adoptively transfer purified B cells from wild-type or ST6Gal I(-/-) mice into B cell-deficient (microMT(-/-)) mice. Recipient mice that received ST6Gal I(-/-) B cells demonstrated reduced influenza-specific IgM levels, but similar levels of influenza-specific IgG, compared with mice that received wild-type B cells. These data suggest that a B cell intrinsic defect partially contributes to the impaired antiviral humoral response.
The Journal of Immunology 05/2009; 182(8):4721-7. · 5.79 Impact Factor
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ABSTRACT: Although memory B cells (B(Mem)) contribute significantly to resistance to infection, B(Mem) population characteristics that may relate to protective efficacy have received little attention. Here, we report a comprehensive quantitative analysis of virus-specific IgG and IgA B(Mem) dispersion after transient influenza pneumonia in mice. From early in the response, B(Mem) circulated continuously and dispersed widely to secondary lymphoid tissues. However, a complicated picture emerged with B(Mem) frequency differences between secondary lymphoid tissues indicating an influence of local tissue factors on trafficking. B(Mem) numbers increased and stabilized at tissue-specific frequencies without contraction of the B(Mem) pool during the period of analysis. The lung was notable as a nonsecondary lymphoid tissue where a rapid influx of IgG and IgA B(Mem) established relatively high frequencies that were maintained long term. Our findings provide insights into the pattern of B(Mem) dispersion, and emphasize the lung as a complex repository of immune memory after local infection.
Proceedings of the National Academy of Sciences 04/2008; 105(9):3485-90. · 9.68 Impact Factor
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ABSTRACT: We compared the herpes simplex virus type 1 (HSV)-specific memory B cell (MBC) populations generated by footpad and intranasal infection in mice. Both routes of infection generated transient antibody-secreting cell responses in the draining lymph nodes and spleen, and sustained circulating IgG. HSV-specific IgG MBCs, analyzed by limiting dilution assay approximately 8 weeks after infection, were distributed in a range of lymph nodes and in the spleen and Peyer's patches. Overall, the route of infection had little effect on the MBC frequency in each anatomical location. Interestingly, after both routes of infection there was a trend towards preferential MBC accumulation in the mediastinal lymph node. Intravaginal challenge of mice primed by footpad or intranasal infection generated similar secondary IgG responses. Our findings indicate that the widespread dispersion of MBCs to lymphoid tissues throughout the body is largely independent of the route of infection, but may be influenced by tissue-specific factors.
Virology 04/2007; 360(1):136-42. · 3.35 Impact Factor
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ABSTRACT: Complete characterization of the B cell response to infection or vaccination is dependent on accurate quantitation of the memory B cell (MBC) pool. An established method for measuring MBC frequencies is limiting dilution analysis based on in vitro stimulation of MBCs to divide and differentiate into antibody-secreting cells (ASCs). The presence of specific antibody then serves to identify cultures positive for precursor MBCs. The sensitivity of this approach is critically dependent on optimal in vitro MBC activation. To develop a limiting dilution assay (LDA) for measuring influenza-specific MBC frequencies, we evaluated strategies for the in vitro stimulation of influenza-specific MBCs. An ELISPOT assay to enumerate influenza-specific IgG ASCs was used as the readout for MBC activation. Culture of influenza-specific MBCs with influenza-infected splenocytes was effective for MBC activation, but T cell-associated factors were required for optimal LDA sensitivity and clonal expansion of activated MBCs. However, optimal influenza-specific MBC activation was T cell-independent when MBCs were simply cultured with beta-propiolactone (BPL)-inactivated influenza virus particles (BPL-flu). BPL-flu did not stimulate naïve B cells to produce influenza-specific IgG, demonstrating that only MBCs were activated. In addition, BPL-flu acted selectively and only activated influenza-specific MBCs, not MBCs of other specificities. Analysis of influenza-specific MBC frequencies in different anatomical locations in influenza-immune mice established that in vitro stimulation with BPL-flu provided the basis for a sensitive and reproducible LDA. Extending our studies to the herpes simplex virus (HSV) system, we demonstrated that HSV-specific MBCs cultured with BPL-inactivated HSV were selectively activated to IgG secretion in the absence of T cells. Our studies identify BPL-inactivated viral particles as a valuable tool for selective, T cell-independent activation of virus-specific MBCs in vitro. This strategy eliminates the influence of poorly defined T cell-associated factors on MBC frequency determinations.
Journal of Immunological Methods 07/2006; 313(1-2):110-8. · 2.20 Impact Factor
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ABSTRACT: The severity of disease caused in humans by H5N1 influenza viruses remains unexplained. The NS gene of Hong Kong H5N1/97 viruses was shown to contribute to high pathogenicity of reassortants in a pig model. However, the molecular pathogenesis and host immune response underlying this phenomenon remain unclear. Here, in a mouse model, H1N1 A/Puerto Rico/8/34 (PR/8) reassortants that contained the H5N1/97 NS gene, the H5N1/01 NS gene, or an altered H5N1/97 NS gene encoding a Glu92-->Asp substitution in NS1 was studied. The pathogenicity of reassortant viruses, the induction of cytokines and chemokine CXCL1 (KC) in the lungs and specific B- and T-cell responses was characterized. In mice infected with reassortant virus containing the H5N1/97 NS gene, the mouse lethal dose (50%) and lung virus titres were similar to those of PR/8, which is highly pathogenic to mice. This reassortant virus required two more days than PR/8 to be cleared from the lungs of infected mice. Reassortants containing the altered H5N1/97 NS gene or the H5N1/01 NS gene demonstrated attenuated pathogenicity and lower lung titres in mice. Specific B- and T-cell responses were consistent with viral pathogenicity and did not explain the delayed clearance of the H5N1/97 NS reassortant. The reassortant induced elevated pulmonary concentrations of the inflammatory cytokines IL1alpha, IL1beta, IL6, IFN-gamma and chemokine KC, and decreased concentrations of the anti-inflammatory cytokine IL10. This cytokine imbalance is reminiscent of the clinical findings in two humans who died of H5N1/97 infection and may explain the unusual severity of the disease.
Journal of General Virology 04/2005; 86(Pt 4):1121-30. · 3.36 Impact Factor
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ABSTRACT: Contact-mediated interactions between CD4+ T cells and B cells are considered crucial for T cell-dependent B cell responses. To investigate the ability of activated CD4+ T cells to drive in vivo B cell responses in the absence of key cognate T-B interactions, we constructed radiation bone marrow chimeras in which CD4+ T cells would be activated by wild-type (WT) dendritic cells, but would interact with B cells that lacked expression of either major histocompatibility complex class II (MHC II) or CD40. B cell responses were assessed after influenza virus infection of the respiratory tract, which elicits a vigorous, CD4+ T cell-dependent antibody response in WT mice. The influenza-specific antibody response was strongly reduced in MHC II knockout and CD40 knockout mice. MHC II-deficient and CD40-deficient B cells in the chimera environment also produced little virus-specific immunoglobulin (Ig)M and IgG, but generated a strong virus-specific IgA response with virus-neutralizing activity. The IgA response was entirely influenza specific, in contrast to the IgG2a response, which had a substantial nonvirus-specific component. Our study demonstrates a CD4+ T cell-dependent, antiviral IgA response that is generated in the absence of B cell signaling via MHC II or CD40, and is restricted exclusively to virus-specific B cells.
Journal of Experimental Medicine 11/2003; 198(7):1011-21. · 13.85 Impact Factor
