Dokument: The Role of Innate Immune Triggers for the Induction of Poxviral Vectored Cytotoxic T Cell Responses
| Titel: | The Role of Innate Immune Triggers for the Induction of Poxviral Vectored Cytotoxic T Cell Responses | |||||||
| Weiterer Titel: | Die Rolle von innaten Immuntriggern für die Induktion von pockenviralen zytotoxischen T-Zellantworten | |||||||
| URL für Lesezeichen: | https://docserv.uni-duesseldorf.de/servlets/DocumentServlet?id=59737 | |||||||
| URN (NBN): | urn:nbn:de:hbz:061-20220609-111616-1 | |||||||
| Kollektion: | Dissertationen | |||||||
| Sprache: | Englisch | |||||||
| Dokumententyp: | Wissenschaftliche Abschlussarbeiten » Dissertation | |||||||
| Medientyp: | Text | |||||||
| Autor: | Barnowski, Cornelia [Autor] | |||||||
| Dateien: |
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| Beitragende: | Prof. Dr. Drexler, Ingo [Gutachter] Prof. Dr. Heise, Henrike [Gutachter] | |||||||
| Stichwörter: | Modified Vaccinia Virus Ankara, Poxviruses, Innate Immune Triggers, Antigen Presentation, Antigen Cross-Presentation | |||||||
| Dewey Dezimal-Klassifikation: | 500 Naturwissenschaften und Mathematik » 570 Biowissenschaften; Biologie | |||||||
| Beschreibungen: | Das modifizierte Vacciniavirus Ankara (MVA) wird derzeit aufgrund seines hohen Sicherheitsprofils und seiner Fähigkeit effiziente CD8+ T-Zell-Antworten zu induzieren, als vielversprechender Impfstoffvektor untersucht. Da die MVA-Infektion mit einer massiven Apoptose einhergeht, ist die Zeit für eine effiziente Stimulation von CD8+ T-Zellen durch direkt infizierte dendritische Zellen (DCs) begrenzt, und die Kreuzpräsentation von Antigenen durch nicht infizierte DCs, gewinnt im Verlauf der Infektion immer mehr an Bedeutung. Der innate Immuntrigger, der zur funktionellen Aktivierung der kreuzpräsentierenden DCs während einer MVA-Infektion führt, ist jedoch nach wie vor unbekannt. Abgesehen von der Untersuchung der zugrundeliegenden Mechanismen der Kreuzpräsentation in Presenter-Zellen wurde der Rolle der Signaltransduktion in der Feederzelle bei der Aktivierung von kreuzpräsentierenden DCs im Allgemeinen, und insbesondere während einer Infektion mit MVA, bisher nur wenig Aufmerksamkeit geschenkt. Dabei könnte das detaillierte Wissen über die Mechanismen, die DCs stimulieren, um effiziente CD8+ T-Zell-Antworten zu induzieren, zur Entwicklung von MVA-basierten Impfstoffen beitragen. Daher zielt diese Studie darauf ab, die besonderen angeborenen Immunmechanismen in MVA-infizierten Feederzellen zu untersuchen, die die Aktivierung der Kreuzpräsentation durch DCs und somit zur Stimulierung von pockenvirus-spezifischen CD8+ T-Zell-Reaktionen führt.Modified vaccinia virus Ankara (MVA) is currently being investigated as a promising vaccine vector, due to its high safety profile and its ability to induce efficient CD8+ T cell responses. Since MVA infection is accompanied by massive apoptosis, the time available for efficient stimulation of CD8+ T cells by directly infected dendritic cells (DCs) is limited, and cross-presentation of antigens by uninfected DCs gains more and more relevance over the course of infection. However, the innate immune trigger leading to the functional activation of cross-presenting DCs during MVA infection remains elusive. Apart from investigation of the underlying mechanisms of cross- presentation in presenter cells, little attention has been paid to the role of feeder cell signaling in the licensing of cross-presenting DCs in general, and in particular during infection with MVA. It is clear that detailed knowledge of the mechanisms that stimulate DCs to induce efficient CD8+ T cell responses would contribute to the development of MVA-based vaccines. Thus, this study aims to investigate the particular innate immune signaling pathways in MVA-infected feeder cells that trigger the activation of cross- presentation by DCs for the stimulation of poxvirus-specific CD8+ T cell responses.
Using Cytarabine (AraC) to study MVA replication, I observed that cross-presentation of early expressed antigens by bone marrow derived dendritic cells (BMDCs) is abolished following AraC treatment, despite intact protein synthesis in the MVA- infected and AraC-treated feeder cells. By analyzing the transcriptome of these feeder cells, as well as of BMDCs derived from feeder cell-BMDC-cocultures, I was able to obtain candidate target genes that might be involved in the activation of BMDCs for antigen cross-presentation. After silencing several target genes in feeder cells using the gene-editing technology CRISPR/Cas9, these genetically modified cells were characterized for their ability to functionally activate cross-presentation competent BMDCs. I also studied the relevance of stimulator of interferon genes (STING) in the feeder as well as presenter cell to stimulate antigen cross-presentation, because of the crucial role of the cGAS-STING pathway in the detection of MVA (1). Here, I demonstrate that STING signaling during infection with MVA was not only of remarkable importance in the directly infected BMDC for the induction of type I interferons (I IFNs) and subsequent BMDC maturation but also relevant in the cross- presenting BMDC. However, STING has rather a supportive role for the stimulation of antigen cross-presentation in cross-presentation competent BMDCs. Despite the 1. Summary 1 essential role of STING in the induction of I IFNs in directly infected and cross- presenting BMDCs, my findings suggest that feeder cell signaling might also be critical for the activation of antigen cross-presentation. Surprisingly, I observed a striking resemblance between AraC-treated feeder cells, and those deficient in toll-like receptor adaptor molecule 2 (TRIF)-, purinergic receptor P2X, ligand-gated ion channel 7 (P2RX7) or apoptosis-associated speck-like protein containing a CARD (ASC), in that all were unable to stimulate cross-presentation by BMDCs during infection with MVA. My data further support the idea that P2RX7- or ASC-deficient, as well as AraC- treated feeder cells, fail to activate a shared pattern recognition receptor (PRR) or innate immune signaling pathway, resulting in the inability to attract phagocytes. As a result, these feeder cells are unable to properly activate cross-presentation by BMDCs, and neither are the poxviral CD8+ T cell responses stimulated. Due to the importance of signaling by TRIF, P2RX7 and ASC in the ability of feeder cells to activate cross- presentation competent BMDCs during MVA infection, the inflammasome is most likely to be involved in this process. Since I was able to show that the feeder cell phenotype is clearly of importance for the functional activation of cross-presentation competent BMDCs, a more detailed analysis is required to fully understand the exact mechanisms of feeder cell signaling during MVA-infection. Most importantly, this research should contribute to a better understanding of poxvirus-vectored CD8+ T cell responses. Furthermore, this study hopes to highlight the importance of feeder cell signaling for the efficient induction of antigen cross-presentation by DCs during viral infections and extend our knowledge beyond the well-known role of DCs. | |||||||
| Lizenz: |  Urheberrechtsschutz | |||||||
| Fachbereich / Einrichtung: | Mathematisch- Naturwissenschaftliche Fakultät | |||||||
| Dokument erstellt am: | 09.06.2022 | |||||||
| Dateien geändert am: | 09.06.2022 | |||||||
| Promotionsantrag am: | 26.01.2022 | |||||||
| Datum der Promotion: | 20.05.2022 |
