1,721,033 research outputs found
Differential Induction of Lung-Resident Memory T Cells by Mucosal Viral Vector Immunization or Influenza A Virus Infection
Full text linkLung tissue-resident memory T cells (TRM) are critical for the local control of respiratory tract infections caused by influenza A viruses (IAV). However, the exact mechanisms of TRM stimulation and maintenance are still unknown, rendering the induction of protective TRM responses by vaccination an ambitious goal.
To obtain deeper insights into the biology of TRM, we compared TRM populations induced by mucosal immunization using adenoviral vector vaccines with those induced by natural IAV infection. The vaccine-mediated immune response was potentiated by simultaneous administration of vector-encoded IL-1β as an adjuvant. In a longitudinal study, phenotypic and functional TRM responses were assessed in mice up to 210 days via flow cytometric analyses. Interestingly, immunization stimulated longer-lasting and potentially less cytotoxic TRM responses in the lung compared to IAV infection. Immunohistology showed that these antigen-specific CD8+ T cells induced by vaccination were located throughout the lung tissue, whereas TRM triggered by IAV infection tended to surround bronchus-associated B-cell clusters. Moreover, immunization and infection resulted in distinct gene profiles of influenza-specific CD8+ T cells identified by single-cell RNA sequencing. However, despite many differences, both TRM populations provided protection against infection with a heterosubtypic IAV strain, resulting in an expansion of cognate antigen-specific TRM. Considering the fate of pre-existing TRM in case of subsequent inflammatory events, neither unrelated secondary virus infection nor bacterial inflammation had a negative impact on the survival of present TRM. Rather, we observed the co-existence of various TRM populations with different antigen specificities.
In the further course, we extended our analyses to pigs as a natural host model for influenza infections, where we confirmed substantial differences in IAV-specific TRM responses. Also in this large animal model, both prior infection and mucosal immunization induced strong T-cell responses against the conserved nucleoprotein. Additionally, mucosal vaccination, and especially IL-1β-adjuvanted vaccination, was associated with increased functional CD8+ T-cell responses compared to primary IAV infection. Nevertheless, none of the treatment groups showed elevated protection against heterosubtypic H3N2 challenge. Only in the porcine model, but not in the mouse model, co-delivery of IL-1β increased lung pathology after vaccination despite unchanged viral load.
In conclusion, we observed a great heterogeneity among the different TRM populations depending in the inductive trigger. Furthermore, we were able to induce protective immune responses in mice and pigs by mucosal immunization and natural infection, but the mechanisms of heterosubtypic protection may differ between the two species
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Eine mukosale Krebsimpfung induziert gewebeständige Gedächtnis-T-Zellen und schützt vor pulmonalen Brustkrebs-Metastasen
Full text linkBreast cancer displays a good prognosis with a 5-year survival of 85%. However, if tumor cells spread to the lungs, the 5-year survival rate drops to only 12%. Remarkably, the presence of tumor-infiltrating lymphocytes (TIL) correlates with an improved prognosis in many cancer types, particularly for T cells with a tissue-resident memory T cell (TRM) phenotype.
In this project, we established a mucosal vaccine that promotes tumor-specific TRM in the lungs to prevent and treat pulmonary metastases in a 4T1 breast cancer model. The adenoviral (Ad) vector vaccine encodes for the endogenous tumor-antigens (TA) melanoma-associated antigen B (Mage-b) and the gp70 AH1. Additionally, vector-encoded Interleukin (IL)-1β (AdIL1β) was co-delivered to harness its TRM-promoting properties. Immunogenicity studies demonstrated robust antigen-specific CD103+/-CD69+ TRM responses induced by mucosal vaccination in mice. The co-delivery of AdIL1β further increased the immunogenicity and increased the formation of vaccine antigen-specific TRM.
In a prophylactic setting, the mucosal vaccination strategy reduced the pulmonary tumor burden significantly, while a systemic vaccination approach could not achieve a significant decline. Nevertheless, systemic and mucosal vaccination were both able to prolong survival. Utilizing the immunomodulatory drug FTY720 to inhibit infiltration of systemic T cells into the lung, we could prove that vaccine-induced mucosal TRM contribute to the protective efficacy of the mucosal vaccination.
Vaccine efficacy was further assessed in a therapeutic vaccination setting, in which the vaccination was given in presence of pre-existing pulmonary metastases. We observed a pronounced T cell infiltration into metastases. However, a single shot vaccination did not lower the metastatic burden and did not improve the survival kinetics. To prolong the therapeutic window for the development of vaccine-induced TRM, vaccination was combined with state-of-the art treatments currently used in the clinical management of metastasized breast cancer. Among different combinatory treatments investigated in this thesis, therapeutic vaccination together with stereotactic radiotherapy (RT) achieved partial control of established pulmonary metastases. Notably, a systemic prime – mucosal boost vaccination schedule alone resulted in therapeutic efficacy of the vaccine and was further improved by combination with radiotherapy.To test the transferability of the mucosal vaccination approach to a second highly lung-metastasizing cancer, we implemented an MC38 colon carcinoma model but were unable to demonstrate vaccine efficacy here.
In this work, we demonstrate the efficacy of a mucosal vaccine strategy in a lung-metastasized breast cancer model. The change in focus from a formerly cytotoxic, broad cancer treatment to a precise endogenous immune modulation shifts cancer therapy approaches. Harnessing the unique and powerful characteristics of tumor-specific TRM by vaccination might represent a novel treatment option for breast cancer patients in the future. A rational combination of such vaccines, applied in carefully adapted vaccination schemes, with state-of-the-art treatments might enable synergistic therapy effects and eventually improve the prognosis for breast cancer patients with a previously poor life expectancy.Brustkrebs hat eine günstige Prognose mit einer 5-Jahres-Überlebensrate von 85%. Breiten sich die Tumorzellen jedoch auf die Lunge aus, sinkt die 5-Jahres-Überlebensrate drastisch auf nur noch 12%. Das Vorhandensein tumorinfiltrierender T-Zellen korreliert bei vielen Krebsarten mit einer verbesserten Prognose, insbesondere wenn die T-Zellen einen gewebeständigen Gedächtnis-T-Zell-Phänotyp (engl. tissue-resident memory T cells; TRM) aufweisen.
In diesem Projekt wurde ein mukosaler Impfstoff entwickelt, der tumorspezifische TRM in der Lunge induziert, um Lungenmetastasen in einem 4T1 Brustkrebsmodell zu verhindern oder zu behandeln. Der adenovirale (Ad) Vektorimpfstoff kodiert für die endogenen Tumorantigene (TA) Melanom-assoziiertes Antigen B (Mage-b) und gp70 AH1. Zusätzlich wurde vektorkodiertes Interleukin (IL)-1β (AdIL1β) verabreicht, um dessen TRM-fördernde Eigenschaften zu nutzen.
Immunogenitätsuntersuchungen zeigten robuste antigenspezifische CD103+/-CD69+ TRM-Antworten auf eine mukosale Impfung bei Mäusen. Die gleichzeitige Verabreichung von AdIL1β erhöhte die Immunogenität und die Bildung von Impfstoff-Antigen-spezifischen TRM weiter.
In einer prophylaktischen Anwendung reduzierte die mukosale Impfstrategie die Lungentumorlast signifikant, während ein systemischer Impfansatz keine signifikante Tumorreduktion erzielen konnte. Allerdings konnten sowohl die systemische als auch die mukosale Impfung die Überlebenszeit verlängern. Mit Hilfe des Immunmodulators FTY720, der die Infiltration systemischer T-Zellen in die Lunge hemmt, konnte gezeigt werden, dass die durch den Impfstoff induzierten mukosalen TRM zur Wirksamkeit der mukosalen Impfung beitragen.
Die Wirksamkeit des Impfstoffs wurde auch in einer therapeutischen Impfung untersucht, bei der der Impfstoff bei bereits bestehenden Lungenmetastasen verabreicht wurde. Es konnte eine ausgeprägte Infiltration der Tumoren mit T-Zellen beobachtet werden. Die einmalige mukosale Impfung führte jedoch weder zu einer Reduktion der Metastasenlast, noch zu einer Verbesserung der Überlebenskinetik. Um das therapeutische Fenster für die Entwicklung von impfstoffinduzierten TRM zu verlängern, wurde die Impfung mit Standardtherapien kombiniert, die derzeit in der klinischen Behandlung von metastasiertem Brustkrebs eingesetzt werden. Von den verschiedenen Kombinationsbehandlungen, führte die stereotaktische Strahlentherapie (RT) in Kombination mit der therapeutischen Impfung zu einer teilweisen Kontrolle der etablierten Lungenmetastasen. Darüber hinaus führte eine systemische Grundimmunisierung gefolgt von einer mukosalen Auffrischimpfung zu einer therapeutischen Wirksamkeit des Impfstoffs, die durch die Kombination mit einer Strahlentherapie weiter verbessert wurde.
Um die Übertragbarkeit des Ansatzes der mukosalen Vakzinierung auf ein anderes Modell für Lungenmetastasen zu testen, wurde ein MC38-Kolonkarzinommodell etabliert, in dem jedoch keine Wirksamkeit des Impfstoffes nachgewiesen werden konnten.
Diese Arbeit zeigt die Wirksamkeit einer mukosalen Impfstrategie in einem Modell für metastasierenden Brustkrebs in der Lunge. Die Verlagerung des Schwerpunkts von einer ehemals zytotoxischen, breit angelegten Krebsbehandlung hin zu einer präzisen endogenen Immunmodulation führt zu einem grundlegenden Wandel in der Krebstherapie. Die Nutzung der einzigartigen Eigenschaften tumorspezifischer TRM durch Impfung könnte in Zukunft eine neue Behandlungsoption für Brustkrebspatientinnen darstellen. Die Kombination solcher Impfstoffe mit Standardtherapien könnte synergistische Therapieeffekte ermöglichen und letztlich die Prognose von Brustkrebspatientinnen mit bisher ungünstiger Prognose verbessern
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
IL-12-Impaired and IL-12-Secreting Dendritic Cells Produce IL-23 upon CD154 Restimulation
No full textSARS-CoV-2 and SARS-CoV Spike-Mediated Cell-Cell Fusion Differ in Their Requirements for Receptor Expression and Proteolytic Activation
No full textCell-cell fusion allows viruses to infect neighboring cells without the need to produce free virus and contributes to tissue damage by creating virus-infected syncytia. Our results demonstrate that the S2′ cleavage site is essential for activation by TMPRSS2 and unravel important differences between SARS-CoV and SARS-CoV-2, among those, greater dependence of SARS-CoV-2 on ACE2 expression and activation by metalloproteases for cell-cell fusion.ABSTRACT
Severe acute respiratory syndrome-related coronavirus 2 (SARS-CoV-2) infects cells through interaction of its spike protein (SARS2-S) with angiotensin-converting enzyme 2 (ACE2) and activation by proteases, in particular transmembrane protease serine 2 (TMPRSS2). Viruses can also spread through fusion of infected with uninfected cells. We compared the requirements of ACE2 expression, proteolytic activation, and sensitivity to inhibitors for SARS2-S-mediated and SARS-CoV-S (SARS1-S)-mediated cell-cell fusion. SARS2-S-driven fusion was moderately increased by TMPRSS2 and strongly by ACE2, while SARS1-S-driven fusion was strongly increased by TMPRSS2 and less so by ACE2 expression. In contrast to that of SARS1-S, SARS2-S-mediated cell-cell fusion was efficiently activated by batimastat-sensitive metalloproteases. Mutation of the S1/S2 proteolytic cleavage site reduced effector cell-target cell fusion when ACE2 or TMPRSS2 was limiting and rendered SARS2-S-driven cell-cell fusion more dependent on TMPRSS2. When both ACE2 and TMPRSS2 were abundant, initial target cell-effector cell fusion was unaltered compared to that of wild-type (wt) SARS2-S, but syncytia remained smaller. Mutation of the S2 cleavage (S2′) site specifically abrogated activation by TMPRSS2 for both cell-cell fusion and SARS2-S-driven pseudoparticle entry but still allowed for activation by metalloproteases for cell-cell fusion and by cathepsins for particle entry. Finally, we found that the TMPRSS2 inhibitor bromhexine, unlike the inhibitor camostat, was unable to reduce TMPRSS2-activated cell-cell fusion by SARS1-S and SARS2-S. Paradoxically, bromhexine enhanced cell-cell fusion in the presence of TMPRSS2, while its metabolite ambroxol exhibited inhibitory activity under some conditions. On Calu-3 lung cells, ambroxol weakly inhibited SARS2-S-driven lentiviral pseudoparticle entry, and both substances exhibited a dose-dependent trend toward weak inhibition of authentic SARS-CoV-2.
IMPORTANCE
Cell-cell fusion allows viruses to infect neighboring cells without the need to produce free virus and contributes to tissue damage by creating virus-infected syncytia. Our results demonstrate that the S2′ cleavage site is essential for activation by TMPRSS2 and unravel important differences between SARS-CoV and SARS-CoV-2, among those, greater dependence of SARS-CoV-2 on ACE2 expression and activation by metalloproteases for cell-cell fusion. Bromhexine, reportedly an inhibitor of TMPRSS2, is currently being tested in clinical trials against coronavirus disease 2019. Our results indicate that bromhexine enhances fusion under some conditions. We therefore caution against the use of bromhexine in high dosages until its effects on SARS-CoV-2 spike activation are better understood. The related compound ambroxol, which similarly to bromhexine is clinically used as an expectorant, did not exhibit activating effects on cell-cell fusion. Both compounds exhibited weak inhibitory activity against SARS-CoV-2 infection at high concentrations, which might be clinically attainable for ambroxol.Deutsche Forschungsgemeinschaft https://doi.org/10.13039/501100001659Wilhelm Sander-Stiftung https://doi.org/10.13039/10000867
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