Multispecific Aspergillus T Cells Selected by CD137 or CD154 Induce Protective Immune Responses Against the Most Relevant Mold Infections

Background. Aspergillus and Mucorales species cause severe infections in patients after hematopoietic stem cell transplantation (HSCT). Induction of antifungal CD4+ T-helper type 1 (Th1) immunity is an appealing strategy to combat these infections. Immunotherapeutic approaches are so far limited because of a lack of antigens inducing protective T cells, their elaborate production, and the need of targeting a broad spectrum of pathogenic fungi. Methods. We examined the response to different Aspergillus fumigatus proteins in healthy individuals and patients after HSCT and compared rapid selection protocols for fungus-specific T cells based on CD137 or CD154 expression. Results. The A. fumigatus proteins Crf1, Gel1, and Pmp20 induced strong Th1 responses in healthy individuals. T cells specific for these antigens expanded in patients with active invasive aspergillosis, indicating their contribution to infection control. Th1 cells specific for the 3 proteins can be selected with similar specificity within 24 hours, based on CD137 or CD154 expression. These cells recognize naturally processed A. fumigatus and the multispecific T-cell lines, directed against all 3 proteins, especially those selected by CD154, additionally cross-react to different Aspergillus and Mucorales species. Conclusions. These findings may form the basis for adoptive T-cell transfer for prophylaxis or treatment in patients with these devastating infection

Host response to fungal infections - how immunology and host genetics could help to identify and treat patients at risk.

In spite of the ever-increasing incidence and poor outcome of invasive fungal infections in immune compromised patients, there is currently no reliable method to accurately predict the risk, to monitor the outcome and to treat these infections. Protective immunity against Candida and Aspergillus depends on a highly coordinated interaction between the innate and adaptive immune systems. Genetic and immunological defects in components of these networks result in increased risk of invasive fungal infections among patients undergoing chemotherapy or transplant recipients. We review the most important genetic and immunological factors that influence human susceptibility to Candida and Aspergillus infections and discuss the potential role of basic research to promote precision medicine for infectious diseases. We discuss how immunogenetic studies can help to provide tools for improved identification of high-risk patients and the development of tailored antifungal therapies

TLR3 essentially promotes protective class I–restricted memory CD8+ T-cell responses to Aspergillus fumigatus in hematopoietic transplanted patients

Aspergillus fumigatus is a model fungal pathogen and a common cause of severe infections and diseases. CD8+ T cells are present in the human and murine T-cell repertoire to the fungus. However, CD8+ T-cell function in infection and the molecular mechanisms that control their priming and differentiation into effector and memory cells in vivo remain elusive. In the present study, we report that both CD4+ and CD8+ T cells mediate protective memory responses to the fungus contingent on the nature of the fungal vaccine. Mechanistically, class I MHC-restricted, CD8+ memory T cells were activated through TLR3 sensing of fungal RNA by cross-presenting dendritic cells. Genetic deficiency of TLR3 was associated with susceptibility to aspergillosis and concomitant failure to activate memory-protective CD8+ T cells both in mice and in patients receiving stem-cell transplantations. Therefore, TLR3 essentially promotes antifungal memory CD8+ T-cell responses and its deficiency is a novel susceptibility factor for aspergillosis in high-risk patients.These studies were supported by the Specific Targeted Research Project ALLFUN (FP7-HEALTH-2009 contract number 260338 to L.R.), by SYBARIS (FP7-HEALTH-2009 contract number 242220 to L.R.), and by the Italian Project AIDS 2010 by the Istituto Superiore di Sanita (contract number 40H40 to L.R.). A.C. and C.C. were supported by fellowships from Fundacao para a Ciencia e Tecnologia, Portugal (contracts SFRH/BPD/46292/2008 and SFRH/BD/65962/2009, respectively)

Fungal vaccines and immunotherapeutics: current concepts and future challenges

Purpose of review The remarkable advances in modern medicine have paradoxically resulted in a rapidly expanding population of immunocompromised patients displaying extreme susceptibility to life-threatening fungal infections. There are currently no licensed vaccines, and the prophylaxis and therapy of fungal infections in at-risk individuals remains challenging, contributing to undesirable mortality and morbidity rates. The design of successful antifungal preventive approaches has been hampered by an insufficient understanding of the dynamics of the host-fungus interaction and the mechanisms that underlie heterogenous immune responses to vaccines and immunotherapy. Recent findings Recent advances in proteomics and glycomics have contributed to the identification of candidate antigens for use in subunit vaccines, novel adjuvants, and delivery systems to boost the efficacy of protective vaccination responses that are becoming available, and several targets are being exploited in immunotherapeutic approaches. Summary We review some of the emerging concepts as well as the inherent challenges to the development of fungal vaccines and immunotherapies to protect at-risk individuals.ThisworkwassupportedbytheNorthernPortugal Regional Operational Programme (NORTE 2020), under the Portugal 2020 Partnership Agreement, through the European Regional Development Fund (FEDER) (NORTE-01-0145-FEDER-000013), and the Fundação para a Ciência e Tecnologia (FCT) (contracts IF/00735/ 2014 to A.C., and SFRH/BPD/96176/2013 to C.C).info:eu-repo/semantics/publishedVersio

Fungi hijack a ubiquitous plant apoplastic endoglucanase to release a ROS scavenging beta-glucan decasaccharide to subvert immune responses

Plant pathogenic and beneficial fungi have evolved several strategies to evade immunity and cope with host-derived hydrolytic enzymes and oxidative stress in the apoplast, the extracellular space of plant tissues. Fungal hyphae are surrounded by an inner insoluble cell wall layer and an outer soluble extracellular polysaccharide (EPS) matrix. Here, we show by proteomics and glycomics that these two layers have distinct protein and carbohydrate signatures, and hence likely have different biological functions. The barley (Hordeum vulgare) β-1,3-endoglucanase HvBGLUII, which belongs to the widely distributed apoplastic glycoside hydrolase 17 family (GH17), releases a conserved β-1,3;1,6-glucan decasaccharide (β-GD) from the EPS matrices of fungi with different lifestyles and taxonomic positions. This low molecular weight β-GD does not activate plant immunity, is resilient to further enzymatic hydrolysis by β-1,3-endoglucanases due to the presence of three β-1,6-linked glucose branches and can scavenge reactive oxygen species. Exogenous application of β-GD leads to enhanced fungal colonization in barley, confirming its role in the fungal counter-defensive strategy to subvert host immunity. Our data highlight the hitherto undescribed capacity of this often-overlooked EPS matrix from plant-associated fungi to act as an outer protective barrier important for fungal accommodation within the hostile environment at the apoplastic plant–microbe interface

Immune Reconstitution After Allogeneic Hematopoietic Stem Cell Transplantation and Association With Occurrence and Outcome of Invasive Aspergillosis

Background. Invasive aspergillosis (IA) remains a leading cause of morbidity and mortality in patients receiving allogeneic hematopoietic stem cell transplantation (HSCT). To date, no reliable immunological biomarkers for management and outcome of IA exist. Here, we investigated reconstitution of antifungal immunity in patients during the first 12 months after HSCT and correlated it with IA. Methods. Fifty-one patients were included, 9 with probable/proven IA. We determined quantitative and qualitative reconstitution of polymorphonuclear (PMN), CD4, CD8, and natural killer (NK) cells against Aspergillus fumigatus over 5 time points and compared the values to healthy donors. Results. Absolute CD4 and CD8 cell counts, antigen-specific T-cell responses, and killing capacity of PMN against A. fumigatus were significantly decreased in all patients over 12 months. In patients with probable/proven IA, reactive oxygen species (ROS) production tended to be lower compared to patients without IA, and absolute NK-cell counts remained below 200 cells/µL. Patients with well-controlled IA showed significantly higher ROS production and NK-cell counts compared to patients with poor outcome. Conclusions. This study highlights the importance of functional PMN, T-cell, and NK-cell immunity for the outcome of IA. Larger multicenter studies should address the potential use of NK-cell counts for the management of antifungal therap

Analyse des Reaktions- und Fluchtverhaltens in Straßentunneln unter Berücksichtigung von Gruppeneffekten

Die Auswertung realer Ereignisse und früherer Studien zeigt, dass Menschen in Extremsituationen oft gemeinschaftlich abgesicherte Fluchtentscheidungen treffen. Die resultierende Gruppendynamik kann sowohl positive als auch negative Auswirkungen auf die Selbstrettung haben. Da Gruppeneffekte im Zusammenhang mit Ereignissen in Tunneln zuvor kaum untersucht oder quantifiziert wurden, hat die Bundesanstalt für Straßenwesen (BASt) im April 2023 das Forschungsvorhaben „Analyse des Reaktions- und Fluchtverhaltens in Straßentunneln unter Berücksichtigung von Gruppeneffekten“ an ein interdisziplinäres Konsortium aus Ingenieur- und Sozialwissenschaften vergeben. Das Forschungsvorhaben verfolgte das Ziel, den Einfluss der Gruppendynamik auf die Selbstrettung in Tunnelsystemen hinsichtlich soziologischer als auch ingenieurtechnischer Aspekte systematisch zu untersuchen. Im Rahmen des Projektes wurden über 60 Versuchspersonen in ein sehr realistisches Szenario eines Unfalls mit Brand in einem Straßentunnel gebracht und ihr Verhalten während der Selbstrettungsphase detailliert analysiert. Die Probandenversuche wurden in den Tunnelanlagen der Forschungseinrichtung Zentrum am Berg (ZaB) in Österreich durchgeführt. Im Ergebnis wurde eine Vielzahl unterschiedlicher Verhaltensweisen von Einzelpersonen und in Gruppenstrukturen dokumentiert, die Motivlagen der Probanden über Interviews transparent gemacht und die Folgen reflektiert. Für die Verhaltensweisen wurden typisierende Schemata entworfen und eine Einordnung nach positiv, ambivalent, problematisch, kritisch oder fatal vorgenommen. Bei den Einzelversuchen wurde deutlich, dass immer mit einer Flucht von oder durch die Gefahrenstelle im eigenen Fahrzeug zu rechnen ist und Einschätzungen zur Gefahrenlage auch von Personen mit professionellem Vorwissen schwer treffen sind. Bei den Gruppenversuchen zeigt sich, dass im hier dargestellten Szenario eher von einer positiven Wirkung des Kollektivs gesprochen werden kann, insofern Ansätze zu problematischem, kritischen oder gar fatalem Verhalten durch Gruppeneffekte korrigiert werden. Wie weit sich die hier dokumentierten Ansätze auch anders auswirken könnten, lässt sich nur über umfangreichere Versuche klären. Die ingenieurmäßige Auswertung der durchgeführten Probandenversuche, bei denen die Reaktionszeiten und die resultierenden Fluchtgeschwindigkeiten sowohl von Gruppenversuchen als auch von einzelnen Referenzpersonen ermittelt wurden, trägt zur Validierung der Basisparameter zum menschlichen Verhalten von Risikomodellen bei. Eine Notwendigkeit zur Anpassung der Methodik zur Bewertung der Sicherheit von Straßentunneln kann aus den Ergebnissen nicht abgeleitet werden. Datei-Upload durch TIBAnalyses of real events and previous studies show that people in extreme situations often decide how to escape based on other people’s behaviour. The resulting group dynamics can have both positive and negative effects on the self-rescue phase. As group effects in connection with incidents in tunnels have hardly been investigated or quantified before, the Federal Highway Research Institute (BASt) awarded the research project ‘Analysis of reaction and escape behaviour in road tunnels taking group effects into account’ to an interdisciplinary consortium of engineers and social scientists in April 2023. The aim of the research project was to systematically analyse the influence of group dynamics on self-rescue in road tunnels with regard to both sociological and engineering aspects. As part of the project, over 60 test persons placed in a very realistic scenario of an accident with fire in a road tunnel and their behaviour during the self-rescue phase was analysed in detail. The subject tests were carried out in the tunnel facilities of the Zentrum am Berg (ZaB) research centre in Austria. As a result, a large number of different behaviours of individuals and in group structures were documented, the motives of the test subjects were made transparent via interviews and the consequences reflected upon. Types of behaviour were developed and categorised as positive, ambivalent, problematic, critical or fatal. In the individual tests, it became clear that an escape from or through the danger zone in one's own vehicle is always to be expected and that assessments of the danger situation are difficult to make even by people with prior professional knowledge. The group tests show that in the scenario described here, it is more likely to speak of a positive effect of the collective, insofar as approaches to problematic, critical or even fatal behaviour are corrected by group effects. The extent to which the approaches documented here could also have a different effect can only be clarified through more extensive tests. The engineering evaluation of the subject experiments carried out, in which the reaction times and the resulting escape velocities of both group experiments and individual reference persons were determined, contributes to the validation of the basic parameters for the human behaviour of risk models. A requirement to adapt the methodology for as- sessing the safety of road tunnels cannot be derived from the results

Linkage Specificity and Role of Properdin in Activation of the Alternative Complement Pathway by Fungal Glycans

Fungal cell walls are predominantly composed of glucans, mannans, and chitin. Recognition of these glycans by the innate immune system is a critical component of host defenses against the mycoses. Complement, an important arm of innate immunity, plays a significant role in fungal pathogenesis, especially the alternative pathway (AP). Here we determine that the glycan monosaccharide composition and glycosidic linkages affect AP activation and C3 deposition. Furthermore, properdin, a positive regulator of the AP, contributes to these functions. AP activation by glycan particles that varied in composition and linkage was measured by C3a generation in serum treated with 10 mM EGTA and 10 mM Mg2+ (Mg-EGTA-treated serum) (AP specific; properdin functional) or Mg-EGTA-treated serum that lacked functional properdin. Particles that contained either β1→3 or β1→6 glucans or both generated large and similar amounts of C3a when the AP was intact. Blocking properdin function resulted in 5- to 10-fold-less C3a production by particulate β1→3 glucans. However, particulate β1→6 glucans generated C3a via the AP only in the presence of intact properdin. Interestingly, zymosan and glucan-mannan particles (GMP), which contain both β-glucans and mannans, also required properdin to generate C3a. The β1→4 glycans chitin and chitosan minimally activated C3 even when properdin was functional. Finally, properdin binding to glucan particles (GP) and zymosan in serum required active C3. Properdin colocalized with bound C3, suggesting that in the presence of serum, properdin bound indirectly to glycans through C3 convertases. These findings provide a better understanding of how properdin facilitates AP activation by fungi through interaction with the cell wall components

Immune recovery in HIV-infected patients after candida esophagitis is impaired despite long-term antiretroviral therapy.

OBJECTIVE Candida esophagitis belongs to the most common AIDS-defining diseases, however, a comprehensive immune pathogenic concept is lacking. DESIGN We investigated the immune status of 37 HIV-1-infected patients from the Swiss HIV cohort study at diagnosis of Candida esophagitis, 1 year before, 1 year later and after 2 years of suppressed HIV RNA. We compared these patients to 3 groups: 37 HIV-1-infected patients without Candida esophagitis but similar CD4 counts as the patients at diagnosis (advanced HIV group), 15 HIV-1-infected patients with CD4 counts >500 cells/μl, CD4 nadir >350 cells/μl and suppressed HIV RNA under combination antiretroviral therapy (cART) (early cART group), and 20 healthy individuals. METHODS We investigated phenotype, cytokine production and proliferative capacity of different immune cells by flow cytometry and ELISpot. RESULTS We found that patients with Candida esophagitis had nearly abolished CD4 proliferation in response to C. albicans, significantly increased percentages of dysfunctional CD4 cells, significantly decreased cytotoxic NK-cell counts and peripheral innate lymphoid cells and significantly reduced IFN-γ and IL-17 production compared to the early cART group and healthy individuals. Most of these defects remained for more than 2 years despite viral suppression. The advanced HIV group without opportunistic infection showed partly improved immune recovery. CONCLUSIONS Our data indicate that Candida esophagitis in HIV-1-infected patients is caused by an accumulation of multiple, partly Candida-specific immunological defects. Long-term immune recovery is impaired, illustrating that specific immunological gaps persist despite cART. These data also support the rationale for early cART initiation to prevent irreversible immune defects