@article{ZieglerWeissSchmittetal.2017, author = {Ziegler, Sabrina and Weiss, Esther and Schmitt, Anna-Lena and Schlegel, Jan and Burgert, Anne and Terpitz, Ulrich and Sauer, Markus and Moretta, Lorenzo and Sivori, Simona and Leonhardt, Ines and Kurzai, Oliver and Einsele, Hermann and Loeffler, Juergen}, title = {CD56 Is a Pathogen Recognition Receptor on Human Natural Killer Cells}, series = {Scientific Reports}, volume = {7}, journal = {Scientific Reports}, number = {6138}, doi = {10.1038/s41598-017-06238-4}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-170637}, year = {2017}, abstract = {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.}, language = {en} } @article{WeissZieglerFliesseretal.2018, author = {Weiss, Esther and Ziegler, Sabrina and Fliesser, Mirjam and Schmitt, Anna-Lena and H{\"u}nniger, Kerstin and Kurzai, Oliver and Morton, Charles-Oliver and Einsele, Hermann and Loeffler, Juergen}, title = {First Insights in NK—DC Cross-Talk and the Importance of Soluble Factors During Infection With Aspergillus fumigatus}, series = {Frontiers in Cellular and Infection Microbiology}, volume = {8}, journal = {Frontiers in Cellular and Infection Microbiology}, doi = {10.3389/fcimb.2018.00288}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-233565}, year = {2018}, abstract = {Invasive aspergillosis (IA) is an infectious disease caused by the fungal pathogen Aspergillus fumigatus that mainly affects immunocompromised hosts. To investigate immune cell cross-talk during infection with A. fumigatus, we co-cultured natural killer (NK) cells and dendritic cells (DC) after stimulation with whole fungal structures, components of the fungal cell wall, fungal lysate or ligands for distinct fungal receptors. Both cell types showed activation after stimulation with fungal components and were able to transfer activation signals to the counterpart not stimulated cell type. Interestingly, DCs recognized a broader spectrum of fungal components and thereby initiated NK cell activation when those did not recognize fungal structures. These experiments highlighted the supportive function of DCs in NK cell activation. Furthermore, we focused on soluble DC mediated NK cell activation and showed that DCs stimulated with the TLR2/Dectin-1 ligand zymosan could maximally stimulate the expression of CD69 on NK cells. Thus, we investigated the influence of both receptors for zymosan, Dectin-1 and TLR2, which are highly expressed on DCs but show only minimal expression on NK cells. Specific focus was laid on the question whether Dectin-1 or TLR2 signaling in DCs is important for the secretion of soluble factors leading to NK cell activation. Our results show that Dectin-1 and TLR2 are negligible for NK cell activation. We conclude that besides Dectin-1 and TLR2 other receptors on DCs are able to compensate for the missing signal.}, language = {en} } @article{MarischenEnglertSchmittetal.2018, author = {Marischen, Lothar and Englert, Anne and Schmitt, Anna-Lena and Einsele, Hermann and Loeffler, Juergen}, title = {Human NK cells adapt their immune response towards increasing multiplicities of infection of Aspergillus fumigatus}, series = {BMC Immunology}, volume = {19}, journal = {BMC Immunology}, number = {39}, doi = {10.1186/s12865-018-0276-6}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-176331}, year = {2018}, abstract = {Background: The saprophytic fungus Aspergillus fumigatus reproduces by generation of conidia, which are spread by airflow throughout nature. Since humans are inhaling certain amounts of spores every day, the (innate) immune system is constantly challenged. Even though macrophages and neutrophils carry the main burden, also NK cells are regarded to contribute to the antifungal immune response. While NK cells reveal a low frequency, expression and release of immunomodulatory molecules seem to be a natural way of their involvement. Results: In this study we show, that NK cells secrete chemokines such as CCL3/MIP-1α, CCL4/MIP-1β and CCL5/RANTES early on after stimulation with Aspergillus fumigatus and, in addition, adjust the concentration of chemokines released to the multiplicity of infection of Aspergillus fumigatus. Conclusions: These results further corroborate the relevance of NK cells within the antifungal immune response, which is regarded to be more and more important in the development and outcome of invasive aspergillosis in immunocompromised patients after hematopoietic stem cell transplantation. Additionally, the correlation between the multiplicity of infection and the expression and release of chemokines shown here may be useful in further studies for the quantification and/or surveillance of the NK cell involvement in antifungal immune responses.}, language = {en} } @article{HellmannLotherWursteretal.2017, author = {Hellmann, Anna-Maria and Lother, Jasmin and Wurster, Sebastian and Lutz, Manfred B. and Schmitt, Anna Lena and Morton, Charles Oliver and Eyrich, Matthias and Czakai, Kristin and Einsele, Hermann and Loeffler, Juergen}, title = {Human and Murine Innate Immune Cell Populations Display Common and Distinct Response Patterns during Their In Vitro Interaction with the Pathogenic Mold Aspergillus fumigatus}, series = {Frontiers in Immunology}, volume = {8}, journal = {Frontiers in Immunology}, number = {1716}, doi = {10.3389/fimmu.2017.01716}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-169926}, year = {2017}, abstract = {Aspergillus fumigatus is the main cause of invasive fungal infections occurring almost exclusively in immunocompromised patients. An improved understanding of the initial innate immune response is key to the development of better diagnostic tools and new treatment options. Mice are commonly used to study immune defense mechanisms during the infection of the mammalian host with A. fumigatus. However, little is known about functional differences between the human and murine immune response against this fungal pathogen. Thus, we performed a comparative functional analysis of human and murine dendritic cells (DCs), macrophages, and polymorphonuclear cells (PMNs) using standardized and reproducible working conditions, laboratory protocols, and readout assays. A. fumigatus did not provoke identical responses in murine and human immune cells but rather initiated relatively specific responses. While human DCs showed a significantly stronger upregulation of their maturation markers and major histocompatibility complex molecules and phagocytosed A. fumigatus more efficiently compared to their murine counterparts, murine PMNs and macrophages exhibited a significantly stronger release of reactive oxygen species after exposure to A. fumigatus. For all studied cell types, human and murine samples differed in their cytokine response to conidia or germ tubes of A. fumigatus. Furthermore, Dectin-1 showed inverse expression patterns on human and murine DCs after fungal stimulation. These specific differences should be carefully considered and highlight potential limitations in the transferability of murine host-pathogen interaction studies.}, language = {en} } @article{CzakaiLeonhardtDixetal.2016, author = {Czakai, Kristin and Leonhardt, Ines and Dix, Andreas and Bonin, Michael and Linde, Joerg and Einsele, Hermann and Kurzai, Oliver and Loeffler, J{\"u}rgen}, title = {Kr{\"u}ppel-like Factor 4 modulates interleukin-6 release in human dendritic cells after in vitro stimulation with Aspergillus fumigatus and Candida albicans}, series = {Scientific Reports}, volume = {6}, journal = {Scientific Reports}, doi = {10.1038/srep27990}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-181185}, year = {2016}, abstract = {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 Kr{\"u}ppel-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.}, language = {en} }