TY  - JOUR
A1  - Tappe, Beeke
A1  - Lauruschkat, Chris D.
A1  - Strobel, Lea
A1  - Pantaleón García, Jezreel
A1  - Kurzai, Oliver
A1  - Rebhan, Silke
A1  - Kraus, Sabrina
A1  - Pfeuffer-Jovic, Elena
A1  - Bussemer, Lydia
A1  - Possler, Lotte
A1  - Held, Matthias
A1  - Hünniger, Kerstin
A1  - Kniemeyer, Olaf
A1  - Schäuble, Sascha
A1  - Brakhage, Axel A.
A1  - Panagiotou, Gianni
A1  - White, P. Lewis
A1  - Einsele, Hermann
A1  - Löffler, Jürgen
A1  - Wurster, Sebastian
T1  - COVID-19 patients share common, corticosteroid-independent features of impaired host immunity to pathogenic molds
JF  - Frontiers in Immunology
N2  - Patients suffering from coronavirus disease-2019 (COVID-19) are susceptible to deadly secondary fungal infections such as COVID-19-associated pulmonary aspergillosis and COVID-19-associated mucormycosis. Despite this clinical observation, direct experimental evidence for severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2)-driven alterations of antifungal immunity is scarce. Using an ex-vivo whole blood stimulation assay, we challenged blood from twelve COVID-19 patients with Aspergillus fumigatus and Rhizopus arrhizus antigens and studied the expression of activation, maturation, and exhaustion markers, as well as cytokine secretion. Compared to healthy controls, T-helper cells from COVID-19 patients displayed increased expression levels of the exhaustion marker PD-1 and weakened A. fumigatus- and R. arrhizus-induced activation. While baseline secretion of proinflammatory cytokines was massively elevated, whole blood from COVID-19 patients elicited diminished release of T-cellular (e.g., IFN-γ, IL-2) and innate immune cell-derived (e.g., CXCL9, CXCL10) cytokines in response to A. fumigatus and R. arrhizus antigens. Additionally, samples from COVID-19 patients showed deficient granulocyte activation by mold antigens and reduced fungal killing capacity of neutrophils. These features of weakened anti-mold immune responses were largely decoupled from COVID-19 severity, the time elapsed since diagnosis of COVID-19, and recent corticosteroid uptake, suggesting that impaired anti-mold defense is a common denominator of the underlying SARS-CoV-2 infection. Taken together, these results expand our understanding of the immune predisposition to post-viral mold infections and could inform future studies of immunotherapeutic strategies to prevent and treat fungal superinfections in COVID-19 patients.
KW  - COVID-19
KW  - immune impairment
KW  - T cells
KW  - granulocytes
KW  - Aspergillus
KW  - Rhizopus
Y1  - 2022
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-283558
SN  - 1664-3224
VL  - 13
ER  - 
TY  - JOUR
A1  - Ruf, Dominik
A1  - Brantl, Victor
A1  - Wagener, Johannes
T1  - Mitochondrial Fragmentation in \(Aspergillus\) \(fumigatus\) as Early Marker of Granulocyte Killing Activity
JF  - Frontiers in Cellular and Infection Microbiology
N2  - The host's defense against invasive mold infections relies on diverse antimicrobial activities of innate immune cells. However, studying these mechanisms in vitro is complicated by the filamentous nature of such pathogens that typically form long, branched, multinucleated and compartmentalized hyphae. Here we describe a novel method that allows for the visualization and quantification of the antifungal killing activity exerted by human granulocytes against hyphae of the opportunistic pathogen Aspergillus fumigatus. The approach relies on the distinct impact of fungal cell death on the morphology of mitochondria that were visualized with green fluorescent protein (GFP). We show that oxidative stress induces complete fragmentation of the tubular mitochondrial network which correlates with cell death of affected hyphae. Live cell microscopy revealed a similar and non-reversible disruption of the mitochondrial morphology followed by fading of fluorescence in Aspergillus hyphae that were killed by human granulocytes. Quantitative microscopic analysis of fixed samples was subsequently used to estimate the antifungal activity. By utilizing this assay, we demonstrate that lipopolysaccharides as well as human serum significantly increase the killing efficacy of the granulocytes. Our results demonstrate that evaluation of the mitochondrial morphology can be utilized to assess the fungicidal activity of granulocytes against A. fumigatus hyphae.
KW  - Aspergillus fumigatus
KW  - killing
KW  - assay
KW  - PMNs
KW  - granulocytes
KW  - mitochondria
KW  - mitochondrial morphology
KW  - fungicidal activity
Y1  - 2018
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-227133
VL  - 8
IS  - 128
ER  -