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  • American Society for Microbiology  (5)
  • 1
    In: Microbiology Spectrum, American Society for Microbiology, Vol. 10, No. 2 ( 2022-04-27)
    Kurzfassung: Avian paramyxovirus 1 (APMV-1), also known as Newcastle disease virus (NDV), causes severe and economically important disease in poultry around the globe. Although a limited amount of APMV-1 strains in urban areas have been characterized, the role of the urban wild bird population as an APMV-1 reservoir is unclear. Because urban birds may have an important role for long-term circulation of the virus, fecal and swab samples were collected by community scientists from wild birds in New York City (NYC), New York, United States. These samples were screened for APMV-1 and genotypically characterized by sequencing of the complete genome. A total of 885 samples were collected from NYC parks and from a local wildlife rehabilitation clinic from October 2020 through June 2021, and 255 samples obtained from 197 birds have been processed to date. Eight birds (4.1%) screened positive for the APMV-1 nucleoprotein gene by conventional reverse transcription PCR (RT-PCR), and two live viruses were isolated via egg culture. A multibasic F protein cleavage sequence, 112 R R K K R F 117 , an indicator of highly pathogenic velogenic APMV-1 strains, was present in the two samples fully sequenced by next generation sequencing. Phylogenetic analysis of the F gene coding sequence classified both isolates into genotype VI, a diverse and predominant genotype responsible for APMV-1 outbreaks in pigeon and dove species worldwide. IMPORTANCE Here we describe the first large-scale effort to screen for APMV-1 in New York City’s wild bird population as part of the New York City Virus Hunters program, a community science initiative. We characterized two isolates of APMV-1, with phylogenetic analyses suggesting diversity in established and circulating strains of pigeon paramyxoviruses. Our isolates are also domestic reference strains for future APMV-1 vaccine developments. Future surveillance in this region may contribute to our understanding of APMV-1’s evolution and genetic diversity, as well as inform poultry husbandry and vaccination practices in New York State.
    Materialart: Online-Ressource
    ISSN: 2165-0497
    Sprache: Englisch
    Verlag: American Society for Microbiology
    Publikationsdatum: 2022
    ZDB Id: 2807133-5
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 2
    In: Microbiology Spectrum, American Society for Microbiology, Vol. 9, No. 2 ( 2021-10-31)
    Kurzfassung: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) emerged in late 2019 and has since caused a global pandemic resulting in millions of cases and deaths. Diagnostic tools and serological assays are critical for controlling the outbreak, especially assays designed to quantitate neutralizing antibody levels, considered the best correlate of protection. As vaccines become increasingly available, it is important to identify reliable methods for measuring neutralizing antibody responses that correlate with authentic virus neutralization but can be performed outside biosafety level 3 (BSL3) laboratories. While many neutralizing assays using pseudotyped virus have been developed, there have been few studies comparing the different assays to each other as surrogates for authentic virus neutralization. Here, we characterized three enzyme-linked immunosorbent assays (ELISAs) and three pseudotyped vesicular stomatitis virus (VSV) neutralization assays and assessed their concordance with authentic virus neutralization. The most accurate assays for predicting authentic virus neutralization were luciferase- and secreted embryonic alkaline phosphatase (SEAP)-expressing pseudotyped virus neutralizations, followed by green fluorescent protein (GFP)-expressing pseudotyped virus neutralization, and then the ELISAs. IMPORTANCE The ongoing COVID-19 pandemic is caused by infection with severe acute respiratory syndrome virus 2 (SARS-CoV-2). Prior infection or vaccination can be detected by the presence of antibodies in the blood. Antibodies in the blood are also considered to be protective against future infections from the same virus. The “gold standard” assay for detecting protective antibodies against SARS-CoV-2 is neutralization of authentic SARS-CoV-2 virus. However, this assay can only be performed under highly restrictive biocontainment conditions. We therefore characterized six antibody-detecting assays for their correlation with authentic virus neutralization. The significance of our research is in outlining the advantages and disadvantages of the different assays and identifying the optimal surrogate assay for authentic virus neutralization. This will allow for more accurate assessments of protective immunity against SARS-CoV-2 following infection and vaccination.
    Materialart: Online-Ressource
    ISSN: 2165-0497
    Sprache: Englisch
    Verlag: American Society for Microbiology
    Publikationsdatum: 2021
    ZDB Id: 2807133-5
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 3
    In: Journal of Virology, American Society for Microbiology, Vol. 91, No. 5 ( 2017-03)
    Kurzfassung: Dengue virus (DENV) is responsible for growing numbers of infections worldwide and has proven to be a significant challenge for vaccine development. We previously demonstrated that CD8 + T cell responses elicited by a dengue live attenuated virus (DLAV) vaccine resemble those observed after natural infection. In this study, we screened peripheral blood mononuclear cells (PBMCs) from donors vaccinated with a tetravalent DLAV vaccine (TV005) with pools of dengue virus-derived predicted major histocompatibility complex (MHC) class II binding peptides. The definition of CD4 + T cell responses after live vaccination is important because CD4 + T cells are known contributors to host immunity, including cytokine production, help for CD8 + T and B cells, and direct cytotoxicity against infected cells. While responses to all antigens were observed, DENV-specific CD4 + T cells were focused predominantly on the capsid and nonstructural NS3 and NS5 antigens. Importantly, CD4 + T cell responses in vaccinees were similar in magnitude and breadth to those after natural infection, recognized the same antigen hierarchy, and had similar profiles of HLA restriction. We conclude that TV005 vaccination has the capacity to elicit CD4 + cell responses closely mirroring those observed in a population associated with natural immunity. IMPORTANCE The development of effective vaccination strategies against dengue virus infection is of high global public health interest. Here we study the CD4 T cell responses elicited by a tetravalent live attenuated dengue vaccine and show that they resemble responses seen in humans naturally exposed to dengue virus. This is an important issue, since it is likely that optimal immunity induced by a vaccine requires induction of CD4 + responses against the same antigens as those recognized as dominant in natural infection. Detailed knowledge of the T cell response may further contribute to the identification of robust correlates of protection against dengue virus.
    Materialart: Online-Ressource
    ISSN: 0022-538X , 1098-5514
    Sprache: Englisch
    Verlag: American Society for Microbiology
    Publikationsdatum: 2017
    ZDB Id: 1495529-5
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 4
    In: Journal of Virology, American Society for Microbiology, Vol. 89, No. 1 ( 2015-01), p. 120-128
    Kurzfassung: The incidence of infection with any of the four dengue virus serotypes (DENV1 to -4) has increased dramatically in the last few decades, and the lack of a treatment or vaccine has contributed to significant morbidity and mortality worldwide. A recent comprehensive analysis of the human T cell response against wild-type DENV suggested an human lymphocyte antigen (HLA)-linked protective role for CD8 + T cells. We have collected one-unit blood donations from study participants receiving the monovalent or tetravalent live attenuated DENV vaccine (DLAV), developed by the U.S. National Institutes of Health. Peripheral blood mononuclear cells from these donors were screened in gamma interferon enzyme-linked immunosorbent spot assays with pools of predicted, HLA-matched, class I binding peptides covering the entire DENV proteome. Here, we characterize for the first time CD8 + T cell responses after live attenuated dengue vaccination and show that CD8 + T cell responses in vaccinees were readily detectable and comparable to natural dengue infection. Interestingly, whereas broad responses to structural and nonstructural (NS) proteins were observed after monovalent vaccination, T cell responses following tetravalent vaccination were, dramatically, focused toward the highly conserved NS proteins. Epitopes were highly conserved in a vast variety of field isolates and able to elicit multifunctional T cell responses. Detailed knowledge of the T cell response will contribute to the identification of robust correlates of protection in natural immunity and following vaccination against DENV. IMPORTANCE The development of effective vaccination strategies against dengue virus (DENV) infection and clinically significant disease is a task of high global public health value and significance, while also being a challenge of significant complexity. A recent efficacy trial of the most advanced dengue vaccine candidate, demonstrated only partial protection against all four DENV serotypes, despite three subsequent immunizations and detection of measurable neutralizing antibodies to each serotype in most subjects. These results challenge the hypothesis that seroconversion is the only reliable correlate of protection. Here, we show that CD8 + T cell responses in vaccinees were readily detectable and comparable to natural dengue virus infection. Detailed knowledge of the T cell response may further contribute to the identification of robust correlates of protection in natural immunity and vaccination against DENV.
    Materialart: Online-Ressource
    ISSN: 0022-538X , 1098-5514
    Sprache: Englisch
    Verlag: American Society for Microbiology
    Publikationsdatum: 2015
    ZDB Id: 1495529-5
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 5
    In: Journal of Virology, American Society for Microbiology, Vol. 91, No. 8 ( 2017-04-15)
    Kurzfassung: A deletion variant of the dengue virus (DENV) serotype 2 (DENV2) Tonga/74 strain lacking 30 nucleotides from its 3′ untranslated region (rDEN2Δ30) has previously been established for use in a controlled human DENV challenge model. To evaluate if this model is appropriate for the derivation of correlates of protection for DENV vaccines on the basis of cellular immunity, we wanted to compare the cellular immune response to this challenge strain to the response induced by natural infection. To achieve this, we predicted HLA class I- and class II-restricted peptides from rDEN2Δ30 and used them in a gamma interferon enzyme-linked immunosorbent spot assay to interrogate CD8 + and CD4 + T cell responses in healthy volunteers infected with rDEN2Δ30. At the level of CD8 responses, vigorous ex vivo responses were detected in approximately 80% of donors. These responses were similar in terms of the magnitude and the numbers of epitopes recognized to the responses previously observed in peripheral blood mononuclear cells from donors from regions where DENV is hyperendemic. The similarity extended to the immunodominance hierarchy of the DENV nonstructural proteins, with NS3, NS5, and NS1 being dominant in both donor cohorts. At the CD4 level, the responses to rDEN2Δ30 vaccination were less vigorous than those to natural DENV infection and were more focused on nonstructural proteins. The epitopes recognized following rDEN2Δ30 infection and natural infection were largely overlapping for both the CD8 (100%) and CD4 (85%) responses. Finally, rDEN2Δ30 induced stronger CD8 responses than other, more attenuated DENV isolates. IMPORTANCE The lack of a known correlate of protection and the failure of a neutralizing antibody to correlate with protection against dengue virus have highlighted the need for a human DENV challenge model to better evaluate the candidate live attenuated dengue vaccines. In this study, we sought to characterize the immune profiles of rDEN2Δ30-infected subjects and to compare the profiles with those for subjects from areas where DENV is hyperendemic. Our data demonstrate that T cell responses to rDENV2Δ30 are largely similar to those to natural infection in terms of specificity, highlighting that the response to this virus in humans is appropriate as a model for the T cell response to primary DENV2 infection.
    Materialart: Online-Ressource
    ISSN: 0022-538X , 1098-5514
    Sprache: Englisch
    Verlag: American Society for Microbiology
    Publikationsdatum: 2017
    ZDB Id: 1495529-5
    Standort Signatur Einschränkungen Verfügbarkeit
    BibTip Andere fanden auch interessant ...
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