TY  - THES
A1  - Kurzai, Oliver
T1  - Molekulare Charakterisierung pH-regulierter Gene bei der humanpathogenen Hefespezies Candida dubliniensis und ihr Nutzen für die epidemiologische Diagnostik
T1  - PH-regulated genes of the pathogenic yeast Candida dubliniensis and their impact in epidemiological diagnostics
N2  - Candida dubliniensis ist eine 1995 erstmals beschriebene pathogene Hefespezies mit enger phylogenetischer Verwandtschaft zu Candida albicans. Sie wird mittels routinemäßig angewendeter Verfahren nicht von C. albicans unterschieden, weil sie als einzige Spezies im Genus Candida neben C. albicans Chlamydosporen ausbilden kann. C. dubliniensis ist bisher vor allem aus dem Oropharynx HIV-positiver Patienten isoliert worden. PHR1 und PHR2 sind funktionell homologe, pH-abhängig exprimierte Gene von C. albicans, deren Produkte essentiell für die Verknüpfung von b-1,3- und b-1,6-Glukan in der Zellwand sind. Die Deletion jedes dieser Gene führt zu einem pH-abhängigen Phänotyp mit aberranter Morphogenese in vitro und reduzierter Virulenz im Tiermodell. In dieser Arbeit werden PHR homologe Gene im Genom von C. dubliniensis charakterisiert. CdPHR1 weist eine Homologie von 90,5 Prozent zu PHR1 und CdPHR2 eine Homologie von 91,7 Prozent zu PHR2 auf. Wie PHR1 wird auch CdPHR1 nur unter neutralen und alkalischen Bedingungen exprimiert, während sich CdPHR2 Transkript, wie das von PHR2, nur unter sauren Bedingungen nachweisen lässt. Die funktionelle Homologie von CdPHR1 zu PHR1 wird durch Komplementation des Phänotyps einer C. albicans phr1 Mutante mit CdPHR1 gezeigt. Dabei erweist sich der native Promoter von CdPHR1 als funktional in C. albicans. Im Modellorganismus Saccharomyces cerevisiae wird CdPHR1 unter Kontrolle seines nativen Promotors dagegen pH-unabhängig exprimiert. Auch die zusätzliche Einführung eines mutierten, dominant aktiven Allels von RIM101, das in C. albicans für die pH-abhängige Genexpression verantwortlich ist, hat darauf keinen Einfluss. In C. glabrata und Aspergillus nidulans findet sich keine Expression von CdPHR1. Basierend auf Sequenzunterschieden zwischen PHR1 und CdPHR1 wird ein PCR-Schnelltest zur Speziesunterscheidung entwickelt. Dieser wird in einer epidemiologischen Studie mit 133 chlamydosporenpositiven klinischen Isolaten evaluiert. 21 oropharyngeale Isolate von 14 HIV-positiven Patienten können so retrospektiv als C. dubliniensis klassifiziert werden, dies entspricht einer Prävalenz von C. dubliniensis in diesem Kollektiv von 30 Prozent. Die Ergebnisse der PCR werden durch Sequenzierung ribosomaler Gene (V3, ITS1, ITS2) bestätigt. Parallel werden phänotypische Tests zur Identifizierung von C. dubliniensis auf ihre diagnostische Validität getestet. Während sich die Chlamydosporenmorphologie der Isolate und die Koloniefärbung auf dem Farbindikatormedium CHROMagar Candida als unzulänglich für die Unterscheidung erweisen und das für C. dubliniensis beschriebene Wachstumsdefizit bei 45°C zwar sensitiv, nicht aber spezifisch für die Identifizierung dieser Spezies ist, korreliert die Koloniemorphologie auf Staib-Agar zu 100 Prozent mit den molekularen Daten. Alle C. dubliniensis Isolate werden in einem biochemischen Assay (Micronaut RC) untersucht, dabei zeigt der Test auf b-Glukosidase Aktivität hohes diskriminatorisches Potenzial. In Resistenztestungen zeigen sich die C. dubliniensis Isolate sensibler als die oropharyngealen C. albicans Isolate gegen gebräuchliche Antimykotika. In dieser Studie kann gezeigt werden, dass C. dubliniensis und C. albicans auf teilweise austauschbare Mechanismen zur Reaktion auf Alterationen des pH-Milieus verfügen. Die pH-abhängige Regulation zellwandassoziierter Gene ist dabei eng mit morphogenetischen Prozessen verbunden. Trotz dieser Ähnlichkeit ist C. dubliniensis nicht nur weniger virulent als C. albicans, sondern zeigt auch ein unterschiedliches epidemiologisches Spektrum, das durch eine Spezialisierung auf oropharyngeale Kolonisation und Infektion bei HIV-positiven Patienten gekennzeichnet ist. Um die Gründe für diese Unterschiede aufzeigen zu können, ist eine verlässliche Identifizierung von C. dubliniensis notwendig. Dazu stellen die präsentierten Daten einerseits einen schnellen und verlässlichen PCR Test, andererseits eine sorgfältige Evaluierung derzeit gebräuchlicher phänotypischer Verfahren vor. Phänotypisch und genotypisch exzellent charakterisierte Isolate beider Spezies stehen für weitere Untersuchungen zur Verfügung.
N2  - Candida dubliniensis is a recently described pathogenic yeast species that is phylogenetically closely related to Candida albicans. In routine clinical diagnostic procedures both species are not differentiated due to the unique ability of C. dubliniensis to form germ-tubes and chlamydospores as C. albicans. Most C. dubliniensis isolates have been recovered from the oropharynx of HIV-infected patients. PHR1 and PHR2 are functionally homologous genes of C. albicans responsible for crosslinking b-1,3- and b-1,6-glucans of the yeast cell wall. These genes are characterized by a unique pattern of pH-dependent transcription. Deletion of each of these genes results in a pH-dependent phenotype with aberrant in vitro morphogenesis and reduced virulence in an animal model. Here, PHR homologous genes of C. dubliniensis are characterized. CdPHR1 is 90.5 per cent homologous to PHR1, CdPHR2 is 91.7 per cent homologous to PHR2. Like PHR1, CdPHR1 is only expressed in neutral to alkaline conditions, whereas CdPHR2 transcript - as with PHR2 - can only be found in acidic conditions. Functional homology of CdPHR1 with PHR1 is shown by complementation of a phr1 phenotype in C. albicans with CdPHR1. The native promoter of CdPHR1 is thereby shown to be functional in C. albicans. In contrast CdPHR1 is expressed in a pH-independent manner in bakers yeast Saccharomyces cerevisiae. This constitutive expression is not altered by additional integration of a dominant active allele of RIM101, encoding the transcription factor, that ensures pH-dependent gene expression in C. albicans. CdPHR1 is not expressed in C. glabrata and Aspergillus nidulans. A rapid PCR-test for discrimination between C. albicans and C. dubliniensis is constructed based on sequence differences between PHR1 and CdPHR1. This test is evaluated in an epidemiological study with 133 chlamydospore-positive clinical yeast isolates. 21 oropharyngeal isolates are retrospectively identified as C. dubliniensis, resulting in a prevalence of 30 per cent in this patient collective. PCR-results are confirmed by sequencing rDNA (V3, ITS1, ITS2). Phenotypic tests for identification of C. dubliniensis are evaluated with respect to their diagnostic potential. Whereas chlamydospore-morphology and colony colour on Chromagar Candida are not suited for reliable discrimination, and the growth deficit of C. dubliniensis at 45°C is sensitive but not specific, colony morphology on Staib agar corresponds 100 per cent to the molecular biology data. All C. dubliniensis isolates are biochemically characterized using the Micronaut RC system. The test for b-glucosidase activity within this system shows a high discriminatory potential. Susceptibility testing reveals, that the C. dubliniensis isolates are more sensitive to antifungals than the C. albicans isolates. C. dubliniensis and C. albicans rely on interchangeable mechanisms to react to the ambient pH. Furthermore, pH-regulated expression of cell wall associated genes is closely linked to morphogenesis. Despite this, C. dubliniensis is not only less virulent than C. albicans but also displays a distinct epidemiology characterized by a preference for oropharyngeal colonialization and infection of HIV-positive patients. To reveal the reasons for this, reliable identification of C. dubliniensis is necessary. For that purpose, a rapid PCR test is introduced together with an evaluation of currently available phenotypic methods. Thoroughly characterized isolates of both species are available for further studies.
KW  - Candida
KW  - albicans
KW  - dubliniensis
KW  - pH
KW  - PHR
KW  - CdPHR
KW  - RIM101
KW  - Zellwand
KW  - Candida
KW  - albicans
KW  - dubliniensis
KW  - pH
KW  - PHR
KW  - CdPHR
KW  - RIM10
KW  - cell wall
Y1  - 2001
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-1182281
ER  - 
TY  - JOUR
A1  - Morton, Charles O.
A1  - Varga, John J.
A1  - Hornbach, Anke
A1  - Mezger, Markus
A1  - Sennefelder, Helga
A1  - Kneitz, Susanne
A1  - Kurzai, Oliver
A1  - Krappmann, Sven
A1  - Einsele, Hermann
A1  - Nierman, William C.
A1  - Rogers, Thomas R.
A1  - Loeffler, Juergen
T1  - The Temporal Dynamics of Differential Gene Expression in Aspergillus fumigatus Interacting with Human Immature Dendritic Cells In Vitro
N2  - No abstract avDendritic cells (DC) are the most important antigen presenting cells and play a pivotal role in host immunity to infectious agents by acting as a bridge between the innate and adaptive immune systems. Monocyte-derived immature DCs (iDC) were infected with viable resting conidia of Aspergillus fumigatus (Af293) for 12 hours at an MOI of 5; cells were sampled every three hours. RNA was extracted from both organisms at each time point and hybridised to microarrays. iDC cell death increased at 6 h in the presence of A. fumigatus which coincided with fungal germ tube emergence; .80% of conidia were associated with iDC. Over the time course A. fumigatus differentially regulated 210 genes, FunCat analysis indicated significant up-regulation of genes involved in fermentation, drug transport, pathogenesis and response to oxidative stress. Genes related to cytotoxicity were differentially regulated but the gliotoxin biosynthesis genes were down regulated over the time course, while Aspf1 was up-regulated at 9 h and 12 h. There was an up-regulation of genes in the subtelomeric regions of the genome as the interaction progressed. The genes up-regulated by iDC in the presence of A. fumigatus indicated that they were producing a pro-inflammatory response which was consistent with previous transcriptome studies of iDC interacting with A. fumigatus germ tubes. This study shows that A. fumigatus adapts to phagocytosis by iDCs by utilising genes that allow it to survive the interaction rather than just up-regulation of specific virulence genes.
KW  - Dendritische Zelle
Y1  - 2011
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-68958
ER  - 
TY  - JOUR
A1  - Leonhardt, Ines
A1  - Spielberg, Steffi
A1  - Weber, Michael
A1  - Albrecht-Eckardt, Daniela
A1  - Bläss, Markus
A1  - Claus, Ralf
A1  - Barz, Dagmar
A1  - Scherlach, Kirstin
A1  - Hertweck, Christian
A1  - Löffler, Jürgen
A1  - Hünniger, Kerstin
A1  - Kurzai, Oliver
T1  - The fungal quorum-sensing molecule farnesol activates innate immune cells but suppresses cellular adaptive immunity
JF  - mBio
N2  - Farnesol, produced by the polymorphic fungus Candida albicans, is the first quorum-sensing molecule discovered in eukaryotes. Its main function is control of C. albicans filamentation, a process closely linked to pathogenesis. In this study, we analyzed the effects of farnesol on innate immune cells known to be important for fungal clearance and protective immunity. Farnesol enhanced the expression of activation markers on monocytes (CD86 and HLA-DR) and neutrophils (CD66b and CD11b) and promoted oxidative burst and the release of proinflammatory cytokines (tumor necrosis factor alpha [TNF-\(\alpha\)] and macrophage inflammatory protein 1 alpha [MIP-1 \(\alpha\)]). However, this activation did not result in enhanced fungal uptake or killing. Furthermore, the differentiation of monocytes to immature dendritic cells (iDC) was significantly affected by farnesol. Several markers important for maturation and antigen presentation like CD1a, CD83, CD86, and CD80 were significantly reduced in the presence of farnesol. Furthermore, farnesol modulated migrational behavior and cytokine release and impaired the ability of DC to induce T cell proliferation. Of major importance was the absence of interleukin 12 (IL-12) induction in iDC generated in the presence of farnesol. Transcriptome analyses revealed a farnesol-induced shift in effector molecule expression and a down-regulation of the granulocyte-macrophage colony-stimulating factor (GM-CSF) receptor during monocytes to iDC differentiation. Taken together, our data unveil the ability of farnesol to act as a virulence factor of C. albicans by influencing innate immune cells to promote inflammation and mitigating the Th1 response, which is essential for fungal clearance.
KW  - human dendritic cells
KW  - Pseudomonas aeruginosa
KW  - induced apoptosis
KW  - cytokine production
KW  - biofilm formation
KW  - Candida albicans
KW  - mouse model
KW  - systemic candidiasis
KW  - oxidative stress
KW  - carcinoma cells
Y1  - 2015
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-143756
VL  - 6
IS  - 2
ER  - 
TY  - JOUR
A1  - Czakai, Kristin
A1  - Leonhardt, Ines
A1  - Dix, Andreas
A1  - Bonin, Michael
A1  - Linde, Joerg
A1  - Einsele, Hermann
A1  - Kurzai, Oliver
A1  - Loeffler, Jürgen
T1  - Krüppel-like Factor 4 modulates interleukin-6 release in human dendritic cells after in vitro stimulation with Aspergillus fumigatus and Candida albicans
JF  - Scientific Reports
N2  - Invasive fungal infections are associated with high mortality rates and are mostly caused by the opportunistic fungi Aspergillus fumigatus and Candida albicans. Immune responses against these fungi are still not fully understood. Dendritic cells (DCs) are crucial players in initiating innate and adaptive immune responses against fungal infections. The immunomodulatory effects of fungi were compared to the bacterial stimulus LPS to determine key players in the immune response to fungal infections. A genome wide study of the gene regulation of human monocyte-derived dendritic cells (DCs) confronted with A. fumigatus, C. albicans or LPS was performed and Krüppel-like factor 4 (KLF4) was identified as the only transcription factor that was down-regulated in DCs by both fungi but induced by stimulation with LPS. Downstream analysis demonstrated the influence of KLF4 on the interleukine-6 expression in human DCs. Furthermore, KLF4 regulation was shown to be dependent on pattern recognition receptor ligation. Therefore KLF4 was identified as a controlling element in the IL-6 immune response with a unique expression pattern comparing fungal and LPS stimulation.
KW  - gene regulation in immune cells
KW  - fungal host response
KW  - Aspergillus fumigatus
KW  - Candida albicans
Y1  - 2016
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-181185
VL  - 6
ER  - 
TY  - JOUR
A1  - Ziegler, Sabrina
A1  - Weiss, Esther
A1  - Schmitt, Anna-Lena
A1  - Schlegel, Jan
A1  - Burgert, Anne
A1  - Terpitz, Ulrich
A1  - Sauer, Markus
A1  - Moretta, Lorenzo
A1  - Sivori, Simona
A1  - Leonhardt, Ines
A1  - Kurzai, Oliver
A1  - Einsele, Hermann
A1  - Loeffler, Juergen
T1  - CD56 Is a Pathogen Recognition Receptor on Human Natural Killer Cells
JF  - Scientific Reports
N2  - Aspergillus (A.) fumigatus is an opportunistic fungal mold inducing invasive aspergillosis (IA) in immunocompromised patients. Although antifungal activity of human natural killer (NK) cells was shown in previous studies, the underlying cellular mechanisms and pathogen recognition receptors (PRRs) are still unknown. Using flow cytometry we were able to show that the fluorescence positivity of the surface receptor CD56 significantly decreased upon fungal contact. To visualize the interaction site of NK cells and A. fumigatus we used SEM, CLSM and dSTORM techniques, which clearly demonstrated that NK cells directly interact with A. fumigatus via CD56 and that CD56 is re-organized and accumulated at this interaction site time-dependently. The inhibition of the cytoskeleton showed that the receptor re-organization was an active process dependent on actin re-arrangements. Furthermore, we could show that CD56 plays a role in the fungus mediated NK cell activation, since blocking of CD56 surface receptor reduced fungal mediated NK cell activation and reduced cytokine secretion. These results confirmed the direct interaction of NK cells and A. fumigatus, leading to the conclusion that CD56 is a pathogen recognition receptor. These findings give new insights into the functional role of CD56 in the pathogen recognition during the innate immune response.
KW  - pattern recognition receptors
KW  - fungal infection
KW  - Aspergillus fumigatus
KW  - natural killer cells
Y1  - 2017
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-170637
VL  - 7
IS  - 6138
ER  - 
TY  - JOUR
A1  - Prauße, Maria T. E.
A1  - Lehnert, Teresa
A1  - Timme, Sandra
A1  - Hünniger, Kerstin
A1  - Leonhardt, Ines
A1  - Kurzai, Oliver
A1  - Figge, Marc Thilo
T1  - Predictive Virtual Infection Modeling of Fungal Immune Evasion in Human Whole Blood
JF  - Frontiers in Immunology
N2  - Bloodstream infections by the human-pathogenic fungi Candida albicans and Candida glabrata increasingly occur in hospitalized patients and are associated with high mortality rates. The early immune response against these fungi in human blood comprises a concerted action of humoral and cellular components of the innate immune system. Upon entering the blood, the majority of fungal cells will be eliminated by innate immune cells, i.e., neutrophils and monocytes. However, recent studies identified a population of fungal cells that can evade the immune response and thereby may disseminate and cause organ dissemination, which is frequently observed during candidemia. In this study, we investigate the so far unresolved mechanism of fungal immune evasion in human whole blood by testing hypotheses with the help of mathematical modeling. We use a previously established state-based virtual infection model for whole-blood infection with C. albicans to quantify the immune response and identified the fungal immune-evasion mechanism. While this process was assumed to be spontaneous in the previous model, we now hypothesize that the immune-evasion process is mediated by host factors and incorporate such a mechanism in the model. In particular, we propose, based on previous studies that the fungal immune-evasion mechanism could possibly arise through modification of the fungal surface by as of yet unknown proteins that are assumed to be secreted by activated neutrophils. To validate or reject any of the immune-evasion mechanisms, we compared the simulation of both immune-evasion models for different infection scenarios, i.e., infection of whole blood with either C. albicans or C. glabrata under non-neutropenic and neutropenic conditions. We found that under non-neutropenic conditions, both immune-evasion models fit the experimental data from whole-blood infection with C. albicans and C. glabrata. However, differences between the immune-evasion models could be observed for the infection outcome under neutropenic conditions with respect to the distribution of fungal cells across the immune cells. Based on these predictions, we suggested specific experimental studies that might allow for the validation or rejection of the proposed immune-evasion mechanism.
KW  - immune evasion
KW  - state-based model
KW  - innate immune response
KW  - polymorphonuclear neutrophils
KW  - whole-blood infection assay
Y1  - 2018
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-197493
SN  - 1664-3224
VL  - 9
IS  - 560
ER  - 
TY  - JOUR
A1  - Walther, Grit
A1  - Wagner, Lysett
A1  - Kurzai, Oliver
T1  - Updates on the taxonomy of Mucorales with an emphasis on clinically important taxa
JF  - Journal of Fungi
N2  - Fungi of the order Mucorales colonize all kinds of wet, organic materials and represent a permanent part of the human environment. They are economically important as fermenting agents of soybean products and producers of enzymes, but also as plant parasites and spoilage organisms. Several taxa cause life-threatening infections, predominantly in patients with impaired immunity. The order Mucorales has now been assigned to the phylum Mucoromycota and is comprised of 261 species in 55 genera. Of these accepted species, 38 have been reported to cause infections in humans, as a clinical entity known as mucormycosis. Due to molecular phylogenetic studies, the taxonomy of the order has changed widely during the last years. Characteristics such as homothallism, the shape of the suspensors, or the formation of sporangiola are shown to be not taxonomically relevant. Several genera including Absidia, Backusella, Circinella, Mucor, and Rhizomucor have been amended and their revisions are summarized in this review. Medically important species that have been affected by recent changes include Lichtheimia corymbifera, Mucor circinelloides, and Rhizopus microsporus. The species concept of Rhizopus arrhizus (syn. R. oryzae) is still a matter of debate. Currently, species identification of the Mucorales is best performed by sequencing of the internal transcribed spacer (ITS) region. Ecologically, the Mucorales represent a diverse group but for the majority of taxa, the ecological role and the geographic distribution remain unknown. Understanding the biology of these opportunistic fungal pathogens is a prerequisite for the prevention of infections, and, consequently, studies on the ecology of the Mucorales are urgently needed.
KW  - Mucorales
KW  - taxonomy
KW  - pathogens
KW  - identification
KW  - ecology
KW  - Circinella
KW  - Lichtheimia
KW  - Mucor
KW  - Rhizomucor
KW  - Rhizopus
Y1  - 2019
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-193081
SN  - 2309-608X
VL  - 5
IS  - 4
ER  - 
TY  - JOUR
A1  - Springer, Jan
A1  - Walther, Grit
A1  - Rickerts, Volker
A1  - Hamprecht, Axel
A1  - Willinger, Birgit
A1  - Teschner, Daniel
A1  - Einsele, Hermann
A1  - Kurzai, Oliver
A1  - Loeffler, Juergen
T1  - Detection of Fusarium Species in Clinical Specimens by Probe-Based Real-Time PCR
JF  - Journal of Fungi
N2  - The mold Fusarium is a ubiquitous fungus causing plant, animal and human infections. In humans, Fusarium spp. are the major cause of eye infections in patients wearing contact lenses or after local trauma. Systemic infections by Fusarium spp. mainly occur in immunosuppressed patients and can disseminate throughout the human body. Due to high levels of resistance to antifungals a fast identification of the causative agent is an urgent need. By using a probe-based real-time PCR assay specific for the genus Fusarium we analysed several different clinical specimens detecting Fusarium spp. commonly found in clinical samples in Germany. Also, a large collection of lung fluid samples of haematological patients was analysed (n = 243). In these, two samples (0.8%) were reproducibly positive, but only one could be confirmed by sequencing. For this case of probable invasive fungal disease (IFD) culture was positive for Fusarium species. Here we describe a rapid, probe-based real-time PCR assay to specifically detect DNA from a broad range of Fusarium species and its application to clinically relevant specimens.
KW  - probe-based real-time PCR
KW  - Fusarium
KW  - bronchoalveolar lavage fluid
KW  - fungal molecular diagnostics
Y1  - 2019
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-193111
SN  - 2309-608X
VL  - 5
IS  - 4
ER  - 
TY  - JOUR
A1  - Apsemidou, Athanasia
A1  - Füller, Miriam Antonie
A1  - Idelevich, Evgeny A.
A1  - Kurzai, Oliver
A1  - Tragiannidis, Athanasios
A1  - Groll, Andreas H.
T1  - Candida lusitaniae breakthrough fungemia in an immuno-compromised adolescent: case report and review of the literature
JF  - Journal of Fungi
N2  - Candida lusitaniae is a rare cause of candidemia that is known for its unique capability to rapidly acquire resistance to amphotericin B. We report the case of an adolescent with grade IV graft-vs.-host disease after hematopoietic cell transplantation who developed catheter-associated C. lusitaniae candidemia while on therapeutic doses of liposomal amphotericin B. We review the epidemiology of C. lusitaniae bloodstream infections in adult and pediatric patients, the development of resistance, and its role in breakthrough candidemia. Appropriate species identification, in vitro susceptibility testing, and source control are pivotal to optimal management of C. lusitaniae candidemia. Initial antifungal therapy may consist of an echinocandin and be guided by in vitro susceptibility and clinical response.
KW  - Candida lusitaniae
KW  - candidemia
KW  - resistance
KW  - breakthrough
KW  - infection
KW  - transplantation
Y1  - 2020
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-220125
SN  - 2309-608X
VL  - 6
IS  - 4
ER  - 
TY  - JOUR
A1  - Weiss, Esther
A1  - Schlegel, Jan
A1  - Terpitz, Ulrich
A1  - Weber, Michael
A1  - Linde, Jörg
A1  - Schmitt, Anna-Lena
A1  - Hünniger, Kerstin
A1  - Marischen, Lothar
A1  - Gamon, Florian
A1  - Bauer, Joachim
A1  - Löffler, Claudia
A1  - Kurzai, Oliver
A1  - Morton, Charles Oliver
A1  - Sauer, Markus
A1  - Einsele, Hermann
A1  - Loeffler, Juergen
T1  - Reconstituting NK Cells After Allogeneic Stem Cell Transplantation Show Impaired Response to the Fungal Pathogen Aspergillus fumigatus
JF  - Frontiers in Immunology
N2  - Delayed natural killer (NK) cell reconstitution after allogeneic stem cell transplantation (alloSCT) is associated with a higher risk of developing invasive aspergillosis. The interaction of NK cells with the human pathogen Aspergillus (A.) fumigatus is mediated by the fungal recognition receptor CD56, which is relocated to the fungal interface after contact. Blocking of CD56 signaling inhibits the fungal mediated chemokine secretion of MIP-1α, MIP-1β, and RANTES and reduces cell activation, indicating a functional role of CD56 in fungal recognition. We collected peripheral blood from recipients of an allograft at defined time points after alloSCT (day 60, 90, 120, 180). NK cells were isolated, directly challenged with live A. fumigatus germ tubes, and cell function was analyzed and compared to healthy age and gender-matched individuals. After alloSCT, NK cells displayed a higher percentage of CD56\(^{bright}\)CD16\(^{dim}\) cells throughout the time of blood collection. However, CD56 binding and relocalization to the fungal contact side were decreased. We were able to correlate this deficiency to the administration of corticosteroid therapy that further negatively influenced the secretion of MIP-1α, MIP-1β, and RANTES. As a consequence, the treatment of healthy NK cells ex vivo with corticosteroids abrogated chemokine secretion measured by multiplex immunoassay. Furthermore, we analyzed NK cells regarding their actin cytoskeleton by Structured Illumination Microscopy (SIM) and flow cytometry and demonstrate an actin dysfunction of NK cells shown by reduced F-actin content after fungal co-cultivation early after alloSCT. This dysfunction remains until 180 days post-alloSCT, concluding that further actin-dependent cellular processes may be negatively influenced after alloSCT. To investigate the molecular pathomechansism, we compared CD56 receptor mobility on the plasma membrane of healthy and alloSCT primary NK cells by single-molecule tracking. The results were very robust and reproducible between tested conditions which point to a different molecular mechanism and emphasize the importance of proper CD56 mobility.
KW  - natural killer cell
KW  - stem cell transplantation
KW  - corticosteroids
KW  - CCL3
KW  - CCL4
KW  - CCL5
Y1  - 2020
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-212581
SN  - 1664-3224
VL  - 11
ER  -