@article{HerrmannMuenstermannStrobeletal.2018, author = {Herrmann, Johannes and Muenstermann, Marcel and Strobel, Lea and Schubert-Unkmeir, Alexandra and Woodruff, Trent M. and Gray-Owen, Scott D. and Klos, Andreas and Johswich, Kay O.}, title = {Complement C5a receptor 1 exacerbates the pathophysiology of N. meningitidis sepsis and is a potential target for disease treatment}, series = {mBio}, volume = {9}, journal = {mBio}, number = {1}, doi = {10.1128/mBio.01755-17}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-175792}, pages = {e01755-17}, year = {2018}, abstract = {Sepsis caused by Neisseria meningitidis (meningococcus) is a rapidly progressing, life-threatening disease. Because its initial symptoms are rather unspecific, medical attention is often sought too late, i.e., when the systemic inflammatory response is already unleashed. This in turn limits the success of antibiotic treatment. The complement system is generally accepted as the most important innate immune determinant against invasive meningococcal disease since it protects the host through the bactericidal membrane attack complex. However, complement activation concomitantly liberates the C5a peptide, and it remains unclear whether this potent anaphylatoxin contributes to protection and/or drives the rapidly progressing immunopathogenesis associated with meningococcal disease. Here, we dissected the specific contribution of C5a receptor 1 (C5aR1), the canonical receptor for C5a, using a mouse model of meningococcal sepsis. Mice lacking C3 or C5 displayed susceptibility that was enhanced by >1,000-fold or 100-fold, respectively, consistent with the contribution of these components to protection. In clear contrast, C5ar1\(^{-/-}\) mice resisted invasive meningococcal infection and cleared N. meningitidis more rapidly than wild-type (WT) animals. This favorable outcome stemmed from an ameliorated inflammatory cytokine response to N. meningitidis in C5ar1\(^{-/-}\) mice in both in vivo and ex vivo whole-blood infections. In addition, inhibition of C5aR1 signaling without interference with the complement bactericidal activity reduced the inflammatory response also in human whole blood. Enticingly, pharmacologic C5aR1 blockade enhanced mouse survival and lowered meningococcal burden even when the treatment was administered after sepsis induction. Together, our findings demonstrate that C5aR1 drives the pathophysiology associated with meningococcal sepsis and provides a promising target for adjunctive therapy. Importance: The devastating consequences of N. meningitidis sepsis arise due to the rapidly arising and self-propagating inflammatory response that mobilizes antibacterial defenses but also drives the immunopathology associated with meningococcemia. The complement cascade provides innate broad-spectrum protection against infection by directly damaging the envelope of pathogenic microbes through the membrane attack complex and triggers an inflammatory response via the C5a peptide and its receptor C5aR1 aimed at mobilizing cellular effectors of immunity. Here, we consider the potential of separating the bactericidal activities of the complement cascade from its immune activating function to improve outcome of N. meningitidis sepsis. Our findings demonstrate that the specific genetic or pharmacological disruption of C5aR1 rapidly ameliorates disease by suppressing the pathogenic inflammatory response and, surprisingly, allows faster clearance of the bacterial infection. This outcome provides a clear demonstration of the therapeutic benefit of the use of C5aR1-specific inhibitors to improve the outcome of invasive meningococcal disease.}, language = {en} } @article{MuenstermannStrobelKlosetal.2019, author = {Muenstermann, Marcel and Strobel, Lea and Klos, Andreas and Wetsel, Rick A. and Woodruff, Trent M. and K{\"o}hl, J{\"o}rg and Johswich, Kay O.}, title = {Distinct roles of the anaphylatoxin receptors C3aR, C5aR1 and C5aR2 in experimental meningococcal infections}, series = {Virulence}, volume = {10}, journal = {Virulence}, number = {1}, doi = {10.1080/21505594.2019.1640035}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-200496}, pages = {677-694}, year = {2019}, abstract = {The complement system is pivotal in the defense against invasive disease caused by Neisseria meningitidis (Nme, meningococcus), particularly via the membrane attack complex. Complement activation liberates the anaphylatoxins C3a and C5a, which activate three distinct G-protein coupled receptors, C3aR, C5aR1 and C5aR2 (anaphylatoxin receptors, ATRs). We recently discovered that C5aR1 exacerbates the course of the disease, revealing a downside of complement in Nme sepsis. Here, we compared the roles of all three ATRs during mouse nasal colonization, intraperitoneal infection and human whole blood infection with Nme. Deficiency of complement or ATRs did not alter nasal colonization, but significantly affected invasive disease: Compared to WT mice, the disease was aggravated in C3ar\(^{-/-}\) mice, whereas C5ar1\(^{-/-}\) and C5ar2\(^{-/-}\) mice showed increased resistance to meningococcal sepsis. Surprisingly, deletion of either of the ATRs resulted in lower cytokine/chemokine responses, irrespective of the different susceptibilities of the mice. This was similar in ex vivo human whole blood infection using ATR inhibitors. Neutrophil responses to Nme were reduced in C5ar1\(^{-/-}\) mouse blood. Upon stimulation with C5a plus Nme, mouse macrophages displayed reduced phosphorylation of ERK1/2, when C5aR1 or C5aR2 were ablated or inhibited, suggesting that both C5a-receptors prime an initial macrophage response to Nme. Finally, in vivo blockade of C5aR1 alone (PMX205) or along with C5aR2 (A8\(^{Δ71-73}\)) resulted in ameliorated disease, whereas neither antagonizing C3aR (SB290157) nor its activation with a "super-agonist" peptide (WWGKKYRASKLGLAR) demonstrated a benefit. Thus, C5aR1 and C5aR2 augment disease pathology and are interesting targets for treatment, whereas C3aR is protective in experimental meningococcal sepsis.}, language = {en} } @article{StrobelJohswich2018, author = {Strobel, Lea and Johswich, Kay O.}, title = {Anticoagulants impact on innate immune responses and bacterial survival in whole blood models of Neisseria meningitidis infection}, series = {Scientific Reports}, volume = {8}, journal = {Scientific Reports}, number = {10225}, doi = {10.1038/s41598-018-28583-8}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-176226}, year = {2018}, abstract = {Neisseria meningitidis (meningococcus) causes invasive diseases such as meningitis or septicaemia. Ex vivo infection of human whole blood is a valuable tool to study meningococcal virulence factors and the host innate immune responses. In order to consider effects of cellular mediators, the coagulation cascade must be inhibited to avoid clotting. There is considerable variation in the anticoagulants used among studies of N. meningitidis whole blood infections, featuring citrate, heparin or derivatives of hirudin, a polypeptide from leech saliva. Here, we compare the influence of these three different anticoagulants, and additionally Mg/EGTA, on host innate immune responses as well as on viability of N. meningitidis strains isolated from healthy carriers and disease cases, reflecting different sequence types and capsule phenotypes. We found that the anticoagulants significantly impact on cellular responses and, strain-dependently, also on bacterial survival. Hirudin does not inhibit complement and is therefore superior over the other anticoagulants; indeed hirudin-plasma most closely reflects the characteristics of serum during N. meningitidis infection. We further demonstrate the impact of heparin on complement activation on N. meningitidis and its consequences on meningococcal survival in immune sera, which appears to be independent of the heparin binding antigens Opc and NHBA.}, language = {en} } @article{PageWallstabeLotheretal.2021, author = {Page, Lukas and Wallstabe, Julia and Lother, Jasmin and Bauser, Maximilian and Kniemeyer, Olaf and Strobel, Lea and Voltersen, Vera and Teutschbein, Janka and Hortschansky, Peter and Morton, Charles Oliver and Brakhage, Axel A. and Topp, Max and Einsele, Hermann and Wurster, Sebastian and Loeffler, Juergen}, title = {CcpA- and Shm2-Pulsed Myeloid Dendritic Cells Induce T-Cell Activation and Enhance the Neutrophilic Oxidative Burst Response to Aspergillus fumigatus}, series = {Frontiers in Immunology}, volume = {12}, journal = {Frontiers in Immunology}, issn = {1664-3224}, doi = {10.3389/fimmu.2021.659752}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-239493}, year = {2021}, abstract = {Aspergillus fumigatus causes life-threatening opportunistic infections in immunocompromised patients. As therapeutic outcomes of invasive aspergillosis (IA) are often unsatisfactory, the development of targeted immunotherapy remains an important goal. Linking the innate and adaptive immune system, dendritic cells are pivotal in anti-Aspergillus defense and have generated interest as a potential immunotherapeutic approach in IA. While monocyte-derived dendritic cells (moDCs) require ex vivo differentiation, antigen-pulsed primary myeloid dendritic cells (mDCs) may present a more immediate platform for immunotherapy. To that end, we compared the response patterns and cellular interactions of human primary mDCs and moDCs pulsed with an A. fumigatus lysate and two A. fumigatus proteins (CcpA and Shm2) in a serum-free, GMP-compliant medium. CcpA and Shm2 triggered significant upregulation of maturation markers in mDCs and, to a lesser extent, moDCs. Furthermore, both A. fumigatus proteins elicited the release of an array of key pro-inflammatory cytokines including TNF-α, IL-1β, IL-6, IL-8, and CCL3 from both DC populations. Compared to moDCs, CcpA- and Shm2-pulsed mDCs exhibited greater expression of MHC class II antigens and stimulated stronger proliferation and IFN-γ secretion from autologous CD4\(^+\) and CD8\(^+\) T-cells. Moreover, supernatants of CcpA- and Shm2-pulsed mDCs significantly enhanced the oxidative burst in allogeneic neutrophils co-cultured with A. fumigatus germ tubes. Taken together, our in vitro data suggest that ex vivo CcpA- and Shm2-pulsed primary mDCs have the potential to be developed into an immunotherapeutic approach to tackle IA.}, language = {en} } @article{ClausHubertBecheretal.2019, author = {Claus, Heike and Hubert, Kerstin and Becher, D{\"o}rte and Otto, Andreas and Pawlik, Marie-Christin and Lappann, Ines and Strobel, Lea and Vogel, Ulrich and Johswich, Kay}, title = {A homopolymeric adenosine tract in the promoter region of nspA influences factor H-mediated serum resistance in Neisseria meningitidis}, series = {Scientific Reports}, volume = {9}, journal = {Scientific Reports}, doi = {10.1038/s41598-019-39231-0}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-200956}, pages = {2736}, year = {2019}, abstract = {Although usually asymptomatically colonizing the human nasopharynx, the Gram-negative bacterium Neisseria meningitidis (meningococcus) can spread to the blood stream and cause invasive disease. For survival in blood, N. meningitidis evades the complement system by expression of a polysaccharide capsule and surface proteins sequestering the complement regulator factor H (fH). Meningococcal strains belonging to the sequence type (ST-) 41/44 clonal complex (cc41/44) cause a major proportion of serogroup B meningococcal disease worldwide, but they are also common in asymptomatic carriers. Proteome analysis comparing cc41/44 isolates from invasive disease versus carriage revealed differential expression levels of the outer membrane protein NspA, which binds fH. Deletion of nspA reduced serum resistance and NspA expression correlated with fH sequestration. Expression levels of NspA depended on the length of a homopolymeric tract in the nspA promoter: A 5-adenosine tract dictated low NspA expression, whereas a 6-adenosine motif guided high NspA expression. Screening German cc41/44 strain collections revealed the 6-adenosine motif in 39\% of disease isolates, but only in 3.4\% of carriage isolates. Thus, high NspA expression is associated with disease, but not strictly required. The 6-adenosine nspA promoter is most common to the cc41/44, but is also found in other hypervirulent clonal complexes.}, language = {en} } @article{TappeLauruschkatStrobeletal.2022, author = {Tappe, Beeke and Lauruschkat, Chris D. and Strobel, Lea and Pantale{\´o}n Garc{\´i}a, Jezreel and Kurzai, Oliver and Rebhan, Silke and Kraus, Sabrina and Pfeuffer-Jovic, Elena and Bussemer, Lydia and Possler, Lotte and Held, Matthias and H{\"u}nniger, Kerstin and Kniemeyer, Olaf and Sch{\"a}uble, Sascha and Brakhage, Axel A. and Panagiotou, Gianni and White, P. Lewis and Einsele, Hermann and L{\"o}ffler, J{\"u}rgen and Wurster, Sebastian}, title = {COVID-19 patients share common, corticosteroid-independent features of impaired host immunity to pathogenic molds}, series = {Frontiers in Immunology}, volume = {13}, journal = {Frontiers in Immunology}, issn = {1664-3224}, doi = {10.3389/fimmu.2022.954985}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-283558}, year = {2022}, abstract = {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.}, language = {en} }