21 research outputs found

    EBNA1-specific CD4+ T cells in healthy carriers of Epstein-Barr virus are primarily Th1 in function

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    The Epstein-Barr virus (EBV) nuclear antigen-1 (EBNA1) maintains the viral episome in all host cells infected with EBV. Recently, EBNA1 was found to be the main EBV latency antigen for CD4+ T cells and could be recognized in cultures from all donors tested. We now identify a polarized Th1 phenotype and obtain evidence for its presence in vivo. When T cells were stimulated with dendritic cells infected with vaccinia vectors expressing EBNA1, 18 of 19 donors secreted IFN-γ, whereas only two of 19 secreted IL-4. Magnetic selection was then used to isolate cells from fresh blood based on EBNA1-induced cytokine production. Specific IFN-γ CD4+ cell lines were established from six of six donors and IL-4 lines from three of six. Only the Th1 lines specifically lysed targets expressing three different sources of EBNA1 protein. When the IgG isotype of EBNA1 plasma Ab\u27s was tested, most specific Ab\u27s were IgG1 and of a high titer, confirming a Th1 response to EBNA1 in vivo. Ab\u27s to other microbial antigens generally were not skewed toward IgG1. Given emerging evidence that Th1 CD4+ T cells have several critical roles in host defense to viral infection and tumors, we propose that EBNA1-specific CD4+ Th1 cells contribute to resistance to EBV and EBV-associated malignancies

    Dendritic Cells Initiate Immune Control of Epstein-Barr Virus Transformation of B Lymphocytes in Vitro

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    The initiation of cell-mediated immunity to Epstein-Barr virus (EBV) has been analyzed with cells from EBV-seronegative blood donors in culture. The addition of dendritic cells (DCs) is essential to prime naive T cells that recognize EBV-latent antigens in enzyme-linked immunospot assays for interferon γ secretion and eradicate transformed B cells in regression assays. In contrast, DCs are not required to control the outgrowth of EBV-transformed B lymphocytes from seropositive donors. Enriched CD4+ and CD8 + T cells mediate regression of EBV-transformed cells in seronegative and seropositive donors, but the kinetics of T-dependent regression occurs with much greater speed with seropositives. EBV infection of DCs cannot be detected by reverse transcription-polymerase chain reaction with primers specific for mRNA for the EBNA1 U and K exons. Instead, DCs capture B cell debris and generate T cells specific for EBV latency antigens. We suggest that the cross-presentation of EBV-latent antigens from infected B cells by DCs is required for the initiation of EBV-specific immune control in vivo and that future EBV vaccine strategies should target viral antigens to DCs

    Human CD4+ T lymphocytes consistently respond to the latent Epstein- Barr virus nuclear antigen EBNA1

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    The Epstein-Barr virus (EBV)-encoded nuclear antigen EBNA1 is critical for the persistence of the viral episome in replicating EBV-transformed human B cells. Therefore, all EBV-induced tumors express this foreign antigen. However, EBNA1 is invisible to CD8+ cytotoxic T lymphocytes because its Gly/Ala repeat domain prevents proteasome-dependent processing for presentation on major histocompatibility complex (MHC) class I. We now describe that CD4+ T cells from healthy adults are primed to EBNA1. In fact, among latent EBV antigens that stimulate CD4+ T cells, EBNA1 is preferentially recognized. We present evidence that the CD4+ response may provide a protective role, including interferon γ secretion and direct cytolysis after encounter of transformed B lymphocyte cell lines (B-LCLs). Dendritic cells (DCs) process EBNA1 from purified protein and from MHC class II-mismatched, EBNA1-expressing cells including B-LCLs. In contrast, B-LCLs and Burkitt\u27s lymphoma lines likely present EBNA1 after endogenous processing, as their capacity to cross-present from exogenous sources is weak or undetectable. By limiting dilution, there is a tight correlation between the capacity of CD4+ T cell lines to recognize autologous B-LCL-expressing EBNA1 and DCs that have captured EBNA1. Therefore, CD4+ T cells can respond to the EBNA1 protein that is crucial for EBV persistence. We suggest that this immune response is initiated in vivo by DCs that present EBV-infected B cells, and that EBNA1-specific CD4+ T cell immunity be enhanced to prevent and treat EBV-associated malignancies

    A randomized, clinical trial to assess the relative efficacy and tolerability of two doses of etoricoxib versus naproxen in patients with ankylosing spondylitis

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    Background This study evaluated two doses of etoricoxib (60 and 90 mg) vs. naproxen 1000 mg in subjects with ankylosing spondylitis (AS). Methods This was a 2-part, double-blind, active comparator-controlled non-inferiority study in subjects ≥18 years of age with AS. In Part I, subjects were randomized to naproxen 1000 mg; etoricoxib 60 mg, and 90 mg. In Part II, naproxen and etoricoxib 90 mg subjects continued on the same treatment; subjects on etoricoxib 60 mg either continued on 60 mg or escalated to 90 mg. Part I (6 weeks) assessed the efficacy of A) etoricoxib 60 mg vs. naproxen and B) 90 mg vs. naproxen according to the time-weighted average change from baseline in Spinal Pain Intensity (SPI; 0–100 mm VAS) (primary endpoint). The non- inferiority margin was set at 8 mm for SPI. In Part II (20 weeks) we evaluated the potential benefit of increasing from 60 to 90 mg (predefined minimum clinically important difference = 6 mm in SPI) for inadequate responders (<50 % improvement from baseline in SPI) onetoricoxib 60 mg in Part I. Results In total, 1015 subjects were randomized to receive etoricoxib 60 mg (N = 702), etoricoxib 90 mg (N = 156), and naproxen 1000 mg (N = 157); 70.9 % were male and the mean age was 45.2 years. There were 919 subjects who completed Part I and all continued to Part II. In Part I, SPI change was non-inferior for both etoricoxib doses vs. naproxen. In both Part I and II, the incidence of adverse events (AEs), drug-related AEs, and serious adverse events (SAEs) were similar between the 3 treatment groups. Conclusion Both doses of etoricoxib were non- inferior to naproxen. All treatments were well tolerated. Etoricoxib 60 and 90 mg effectively control pain in patients with AS, with 60 mg once daily as the lowest effective dose for most patients. Trial registration Clinical Trials Registry # NCT01208207. Registered on 22 September 2010

    Dendritic Cells Initiate Immune Control of Epstein-Barr Virus Transformation of B Lymphocytes In Vitro

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    The initiation of cell-mediated immunity to Epstein-Barr virus (EBV) has been analyzed with cells from EBV-seronegative blood donors in culture. The addition of dendritic cells (DCs) is essential to prime naive T cells that recognize EBV-latent antigens in enzyme-linked immunospot assays for interferon γ secretion and eradicate transformed B cells in regression assays. In contrast, DCs are not required to control the outgrowth of EBV-transformed B lymphocytes from seropositive donors. Enriched CD4+ and CD8+ T cells mediate regression of EBV-transformed cells in seronegative and seropositive donors, but the kinetics of T-dependent regression occurs with much greater speed with seropositives. EBV infection of DCs cannot be detected by reverse transcription–polymerase chain reaction with primers specific for mRNA for the EBNA1 U and K exons. Instead, DCs capture B cell debris and generate T cells specific for EBV latency antigens. We suggest that the cross-presentation of EBV-latent antigens from infected B cells by DCs is required for the initiation of EBV-specific immune control in vivo and that future EBV vaccine strategies should target viral antigens to DCs

    Distribution and Compartmentalization of Human Circulating and Tissue-Resident Memory T Cell Subsets

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    SummaryKnowledge of human T cells derives chiefly from studies of peripheral blood, whereas their distribution and function in tissues remains largely unknown. Here, we present a unique analysis of human T cells in lymphoid and mucosal tissues obtained from individual organ donors, revealing tissue-intrinsic compartmentalization of naive, effector, and memory subsets conserved between diverse individuals. Effector memory CD4+ T cells producing IL-2 predominated in mucosal tissues and accumulated as central memory subsets in lymphoid tissue, whereas CD8+ T cells were maintained as naive subsets in lymphoid tissues and IFN-γ-producing effector memory CD8+ T cells in mucosal sites. The T cell activation marker CD69 was constitutively expressed by memory T cells in all tissues, distinguishing them from circulating subsets, with mucosal memory T cells exhibiting additional distinct phenotypic and functional properties. Our results provide an assessment of human T cell compartmentalization as a new baseline for understanding human adaptive immunity

    Safety, tolerability, and immunogenicity of V114 pneumococcal vaccine compared with PCV13 in a 2+1 regimen in healthy infants : A phase III study (PNEU-PED-EU-2)

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    Background: This phase III study evaluated safety, tolerability, and immunogenicity of V114 (15-valent pneumococcal conjugate vaccine) in healthy infants. V114 contains all 13 serotypes in PCV13 and additional serotypes 22F and 33F. Methods: Healthy infants were randomized to two primary doses and one toddler dose (2+1 regimen) of V114 or PCV13 at 3, 5, and 12 months of age; diphtheria, tetanus, pertussis (DTaP), inactivated poliovirus (IPV), Haemophilus influenzae type b (Hib), hepatitis B (HepB) vaccine was administered concomitantly. Adverse events (AEs) were collected on Days 1–14 following each vaccination. Serotype-specific anti-pneumococcal immunoglobulin G (IgG) was measured 30 days post-primary series, immediately prior to toddler dose, and 30 days post-toddler dose. Primary objectives included non-inferiority of V114 to PCV13 for 13 shared serotypes and superiority of V114 to PCV13 for serotypes 22F and 33F. Results: 1191 healthy infants were randomized to V114 (n = 595) or PCV13 (n = 596). Proportions of participants with solicited AEs and serious AEs were comparable between groups. V114 met non-inferiority criteria for 13 shared serotypes, based on difference in proportions with serotype-specific IgG ≥0.35 μg/mL (lower bound of two-sided 95% confidence interval [CI] >−10.0) and IgG geometric mean concentration (GMC) ratios (lower bound of two-sided 95% CI >0.5) at 30 days post-toddler dose. V114 met superiority criteria for serotypes 22F and 33F, based on response rates (lower bound of two-sided 95% CI >10.0) and IgG GMC ratios (lower bound of two-sided 95% CI >2.0) at 30 days post-toddler dose. Antibody responses to DTaP-IPV-Hib-HepB met non-inferiority criteria, based on antigen-specific response rates. Conclusion: A two-dose primary series plus toddler dose of V114 was well-tolerated in healthy infants. Compared with PCV13, V114 provided non-inferior immune responses to 13 shared serotypes and superior immune responses to additional serotypes 22F and 33F.publishedVersionPeer reviewe

    A phase III, multicenter, randomized, double-blind, active comparator-controlled study to evaluate the safety, tolerability, and immunogenicity of catch-up vaccination regimens of V114, a 15-valent pneumococcal conjugate vaccine, in healthy infants, children, and adolescents (PNEU-PLAN)

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    Background: Despite widespread use of pneumococcal conjugate vaccines (PCVs) in children, morbidity and mortality caused by pneumococcal disease (PD) remain high. In addition, many children do not complete their PCV course on schedule. V114 is a 15-valent PCV that contains two epidemiologically important serotypes, 22F and 33F, in addition to the 13 serotypes present in PCV13, the licensed 13-valent PCV. Methods: This phase III descriptive study evaluated safety and immunogenicity of catch-up vaccination with V114 or PCV13 in healthy children 7 months–17 years of age who were either pneumococcal vaccine-naïve or previously immunized with lower valency PCVs (NCT03885934). Overall, 606 healthy children were randomized to receive V114 (n = 303) or PCV13 (n = 303) via age-appropriate catch-up vaccination schedules in three age cohorts (7–11 months, 12–23 months, or 2–17 years). Results: Similar proportions of children 7–11 months and 2–17 years of age reported adverse events (AEs) in the V114 and PCV13 groups. A numerically greater proportion of children 12–23 months of age reported AEs in the V114 group (79.0%) than the PCV13 group (59.4%). The proportions of children who reported serious AEs varied between different age cohorts but were generally comparable between vaccination groups. No vaccine-related serious AEs were reported, and no deaths occurred. At 30 days after the last PCV dose, serotype-specific immunoglobulin G geometric mean concentrations were comparable between vaccination groups for the 13 shared serotypes and higher in the V114 group for 22F and 33F. Conclusions: Catch-up vaccination with V114 in healthy individuals 7 months–17 years of age was generally well tolerated and immunogenic for all 15 serotypes, including those not contained in PCV13, regardless of prior pneumococcal vaccination. These results support V114 catch-up vaccination in children with incomplete or no PCV immunization per the recommended schedule.publishedVersionPeer reviewe
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