scholarly journals A Heat-Killed Cryptococcus Mutant Strain Induces Host Protection against Multiple Invasive Mycoses in a Murine Vaccine Model

mBio ◽  
2019 ◽  
Vol 10 (6) ◽  
Author(s):  
Yina Wang ◽  
Keyi Wang ◽  
Jorge A. Masso-Silva ◽  
Amariliz Rivera ◽  
Chaoyang Xue
Keyword(s):  
Immune Deficiency ◽  
T Cells ◽  
Fungal Pathogens ◽  
Vaccine Candidate ◽  
Fungal Infections ◽  
Invasive Fungal Infections ◽  
Host Immunity ◽  
Content Type ◽  
A Subunit ◽  
F Box Protein

ABSTRACT Cryptococcus neoformans is a fungal pathogen that infects the lungs and then often disseminates to the central nervous system, causing meningitis. How Cryptococcus is able to suppress host immunity and escape the antifungal activity of macrophages remains incompletely understood. We reported that the F-box protein Fbp1, a subunit of the SCF(Fbp1) E3 ligase, promotes Cryptococcus virulence by regulating host-Cryptococcus interactions. Our recent studies demonstrated that the fbp1Δ mutant elicited superior protective Th1 host immunity in the lungs and that the enhanced immunogenicity of heat-killed fbp1Δ yeast cells can be harnessed to confer protection against a subsequent infection with the virulent parental strain. We therefore examined the use of heat-killed fbp1Δ cells in several vaccination strategies. Interestingly, the vaccine protection remains effective even in mice depleted of CD4+ T cells. This finding is particularly important in the context of HIV/AIDS-induced immune deficiency. Moreover, we observed that vaccinating mice with heat-killed fbp1Δ induces significant cross-protection against challenge with diverse invasive fungal pathogens, including C. neoformans, C. gattii, and Aspergillus fumigatus, as well as partial protection against Candida albicans. Thus, our data suggest that the heat-killed fbp1Δ strain has the potential to be a suitable vaccine candidate against cryptococcosis and other invasive fungal infections in both immunocompetent and immunocompromised populations. IMPORTANCE Invasive fungal infections kill more than 1.5 million people each year, with limited treatment options. There is no vaccine available in clinical use to prevent and control fungal infections. Our recent studies showed that a mutant of the F-box protein Fbp1, a subunit of the SCF(Fbp1) E3 ligase in Cryptococcus neoformans, elicited superior protective Th1 host immunity. Here, we demonstrate that the heat-killed fbp1Δ cells (HK-fbp1) can be harnessed to confer protection against a challenge by the virulent parental strain, even in animals depleted of CD4+ T cells. This finding is particularly important in the context of HIV/AIDS-induced immune deficiency. Moreover, we observed that HK-fbp1 vaccination induces significant cross-protection against challenge with diverse invasive fungal pathogens. Thus, our data suggest that HK-fbp1 has the potential to be a broad-spectrum vaccine candidate against invasive fungal infections in both immunocompetent and immunocompromised populations.

scholarly journals Pulmonary Interleukin-17-Positive Lymphocytes Increase during Pneumocystis murina Infection but Are Not Required for Clearance of Pneumocystis

2017 ◽  
Vol 85 (7) ◽  
Author(s):  
Chiara Ripamonti ◽  
Lisa R. Bishop ◽  
Joseph A. Kovacs
Keyword(s):  
T Cells ◽  
Fungal Infections ◽  
Intracellular Cytokine Staining ◽  
Γδ T Cells ◽  
Interleukin 17 ◽  
Content Type ◽  
Immunosuppressed Patients ◽  
Ifn Γ ◽  
Immunocompetent Mice ◽  
Deficient Mice

ABSTRACT Pneumocystis remains an important pathogen of immunosuppressed patients, causing a potentially life-threatening pneumonia. Despite its medical importance, the immune responses required to control infection, including the role of interleukin-17 (IL-17), which is important in controlling other fungal infections, have not been clearly defined. Using flow cytometry and intracellular cytokine staining after stimulation with phorbol myristate acetate and ionomycin, we examined gamma interferon (IFN-γ), IL-4, IL-5, and IL-17 production by lung lymphocytes in immunocompetent C57BL/6 mice over time following infection with Pneumocystis murina. We also examined the clearance of Pneumocystis infection in IL-17A-deficient mice. The production of both IFN-γ and IL-17 by pulmonary lymphocytes increased during infection, with maximum production at approximately days 35 to 40, coinciding with peak Pneumocystis levels in the lungs, while minimal changes were seen in IL-4- and IL-5-positive cells. The proportion of cells producing IFN-γ was consistently higher than for cells producing IL-17, with peak levels of ∼25 to 30% of CD3+ T cells for the former compared to ∼15% for the latter. Both CD4+ T cells and γδ T cells produced IL-17. Administration of anti-IFN-γ antibody led to a decrease in IFN-γ-positive cells, and an increase in IL-5-positive cells, but did not impact clearance of Pneumocystis infection. Despite the increases in IL-17 production during infection, IL-17A-deficient mice cleared Pneumocystis infection with kinetics similar to C57BL/6 mice. Thus, while IL-17 production in the lungs is increased during Pneumocystis infection in immunocompetent mice, IL-17A is not required for control of Pneumocystis infection.

Identification and in Vitro Susceptibility Pattern of Fungal Pathogens in Immunocompromised Patients with invasive Fungal Infections

2021 ◽  
Vol 30 (3) ◽  
pp. 127-134
Author(s):  
Shaimaa A.S. Selem ◽  
Neveen A. Hassan ◽  
Mohamed Z. Abd El-Rahman ◽  
Doaa M. Abd El-Kareem
Keyword(s):  
Intensive Care ◽  
Fungal Infection ◽  
Fungal Pathogens ◽  
Fungal Infections ◽  
Antifungal Susceptibility ◽  
Invasive Fungal Infections ◽  
Immunocompromised Patients ◽  
University Hospitals ◽  
Vitek 2

Background: In intensive care units, invasive fungal infections have become more common, particularly among immunocompromised patients. Early identification and starting the treatment of those patients with antifungal therapy is critical for preventing unnecessary use of toxic antifungal agents. Objective: The aim of this research is to determine which common fungi cause invasive fungal infection in immunocompromised patients, as well as their antifungal susceptibility patterns in vitro, in Assiut University Hospitals. Methodology: This was a hospital based descriptive study conducted on 120 patients with clinical suspicion of having fungal infections admitted at different Intensive Care Units (ICUs) at Assiut University Hospitals. Direct microscopic examination and inoculation on Sabouraud Dextrose Agar (SDA) were performed on the collected specimens. Isolated yeasts were classified using phenotypic methods such as chromogenic media (Brilliance Candida agar), germ tube examination, and the Vitek 2 system for certain isolates, while the identification of mould isolates was primarily based on macroscopic and microscopic characteristics. Moulds were tested in vitro for antifungal susceptibility using the disc diffusion, and yeast were tested using Vitek 2 device cards. Results: In this study, 100 out of 120 (83.3%) of the samples were positive for fungal infection. Candida and Aspergillus species were the most commonly isolated fungal pathogens. The isolates had the highest sensitivity to Amphotericin B (95 %), followed by Micafungin (94 %) in an in vitro sensitivity survey. Conclusion: Invasive fungal infections are a leading cause of morbidity and mortality in immunocompromised patients, with Candida albicans being the most frequently isolated yeast from various clinical specimens; however, the rise in resistance, especially to azoles, is a major concern.

scholarly journals Prophylaxis of Invasive Fungal Infections: A Review of the Use of Posaconazole

2009 ◽  
Vol 1 ◽  
pp. CMT.S1948
Author(s):  
Curtis D. Collins ◽  
Jeannina A. Smith ◽  
Daniel R. Kaul
Keyword(s):  
At Risk ◽  
Fungal Pathogens ◽  
Fungal Infections ◽  
Case Reports ◽  
Case Series ◽  
Individual Case ◽  
Invasive Fungal Infections ◽  
Cost Of Care ◽  
Therapeutic Drug ◽  
Patients At Risk

Invasive fungal infections (IFIs) cause significant morbidity, mortality, and increased cost of care in patients with hematological malignancies, prolonged (i.e. >7-10 days) treatment induced neutropenia, and other disease states causing underlying immunosuppression. One strategy often used to combat the development of invasive infections is the use of antifungal agents as prophylaxis in at risk patients. Posaconazole is an oral triazole with a useful spectrum of activity against many fungal pathogens of concern in patients at risk for the development of IFIs. Posaconazole is only available in oral formulation and therapeutic drug monitoring may provide value due to variable absorption and serum concentrations. Clinical efficacy and pharmacoeconomic data have demonstrated the utility of posaconazole in the treatment of oropharyngeal candidiasis and for prophylaxis in patients at risk for development of IFIs. Several organizations or expert groups involved in developing guidelines for the management of IFIs recommend posaconazole anti-fungal prophylaxis in patients with AML or MDS and chemotherapy induced neutropenia or significant GVHD. In addition, nonrandomized studies (largely of salvage therapy) and case series suggest that posaconazole may be effective as treatment for invasive aspergillosis, zygomycosis, and coccidiomycosis. Further, small case series or individual case reports suggest activity against other less commonly encountered filamentous fungi and Histoplasma.

scholarly journals Methods of Controlling Invasive Fungal Infections Using CD8+ T Cells

2018 ◽  
Vol 8 ◽  
Author(s):  
Pappanaicken R. Kumaresan ◽  
Thiago Aparecido da Silva ◽  
Dimitrios P. Kontoyiannis
Keyword(s):  
T Cells ◽  
Cd8 T Cells ◽  
Fungal Infections ◽  
Invasive Fungal Infections

scholarly journals Epidemiology and identification of potential fungal pathogens causing invasive fungal infections in a tertiary care hospital in northeast Thailand

2014 ◽  
Vol 52 (8) ◽  
pp. 810-818 ◽  
Author(s):  
Kiatichai Faksri ◽  
Wanlop Kaewkes ◽  
Kunyaluk Chaicumpar ◽  
Prajuab Chaimanee ◽  
Suwin Wongwajana
Keyword(s):  
Fungal Pathogens ◽  
Tertiary Care Hospital ◽  
Fungal Infections ◽  
Tertiary Care ◽  
Invasive Fungal Infections ◽  
Care Hospital ◽  
Northeast Thailand

scholarly journals Fungal Infection in Lung Transplantation

2021 ◽  
Vol 42 (03) ◽  
pp. 471-482
Author(s):  
Cassie C. Kennedy ◽  
Kelly M. Pennington ◽  
Elena Beam ◽  
Raymund R. Razonable
Keyword(s):  
Fungal Infection ◽  
Fungal Pathogens ◽  
Lung Transplant ◽  
Fungal Infections ◽  
Treatment Strategies ◽  
Invasive Fungal Infections ◽  
Molecular Diagnostic ◽  
Candida Spp ◽  
Diagnostic Strategies ◽  
Culture Techniques

AbstractInvasive fungal infections threaten lung transplant outcomes with high associated morbidity and mortality. Pharmacologic prophylaxis may be key to prevent posttransplant invasive fungal infections, but cost, adverse effects, and absorption issues are barriers to effective prophylaxis. Trends in fungal infection diagnostic strategies utilize molecular diagnostic methodologies to complement traditional histopathology and culture techniques. While lung transplant recipients are susceptible to a variety of fungal pathogens, Candida spp. and Aspergillus spp. infections remain the most common. With emerging resistant organisms and multiple novel antifungal agents in the research pipeline, it is likely that treatment strategies will continue to evolve.

scholarly journals Pneumococcal Extracellular Vesicles Modulate Host Immunity

mBio ◽  
2021 ◽  
Author(s):  
Saigopalakrishna S. Yerneni ◽  
Sarah Werner ◽  
Juliana H. Azambuja ◽  
Nils Ludwig ◽  
Rory Eutsey ◽  
...  
Keyword(s):  
T Cells ◽  
Streptococcus Pneumoniae ◽  
Epithelial Cells ◽  
Host Immunity ◽  
Dependent Manner ◽  
Content Type ◽  
Human Macrophages ◽  
Pretreatment Conditions ◽  
M2 Phenotype

Our studies reveal that Streptococcus pneumoniae (pneumococcus) (pEVs) are internalized by macrophages, T cells, and epithelial cells. In vitro , pEVs induce NF-κB activation in a dosage-dependent manner and polarize human macrophages to an alternative (M2) phenotype. In addition, pEV pretreatment conditions macrophages to increase bacteria uptake and such macrophages may act as a reservoir for pneumococcal cells by increasing survival of the phagocytosed bacteria.

scholarly journals Crystal Structures of Full-Length Lanosterol 14α-Demethylases of Prominent Fungal Pathogens Candida albicans and Candida glabrata Provide Tools for Antifungal Discovery

2018 ◽  
Vol 62 (11) ◽  
Author(s):  
Mikhail V. Keniya ◽  
Manya Sabherwal ◽  
Rajni K. Wilson ◽  
Matthew A. Woods ◽  
Alia A. Sagatova ◽  
...  
Keyword(s):  
Candida Albicans ◽  
Crystal Structures ◽  
Candida Glabrata ◽  
Fungal Pathogens ◽  
Catalytic Domain ◽  
Fungal Infections ◽  
Binding Pocket ◽  
Full Length ◽  
Content Type ◽  
Cure Rates

ABSTRACT Targeting lanosterol 14α-demethylase (LDM) with azole drugs provides prophylaxis and treatments for superficial and disseminated fungal infections, but cure rates are not optimal for immunocompromised patients and individuals with comorbidities. The efficacy of azole drugs has also been reduced due to the emergence of drug-resistant fungal pathogens. We have addressed the need to improve the potency, spectrum, and specificity for azoles by expressing in Saccharomyces cerevisiae functional, recombinant, hexahistidine-tagged, full-length Candida albicans LDM (CaLDM6×His) and Candida glabrata LDM (CgLDM6×His) and determining their X-ray crystal structures. The crystal structures of CaLDM6×His, CgLDM6×His, and ScLDM6×His have the same fold and bind itraconazole in nearly identical conformations. The catalytic domains of the full-length LDMs have the same fold as the CaLDM6×His catalytic domain in complex with posaconazole, with minor structural differences within the ligand binding pocket. Our structures give insight into the LDM reaction mechanism and phenotypes of single-site CaLDM mutations. This study provides a practical basis for the structure-directed discovery of novel antifungals that target LDMs of fungal pathogens.

Generation of a multipathogen-specific T-cell product for adoptive immunotherapy based on activation-dependent expression of CD154

Blood ◽  
2011 ◽  
Vol 118 (4) ◽  
pp. 1121-1131 ◽  
Author(s):  
Nina Khanna ◽  
Claudia Stuehler ◽  
Barbara Conrad ◽  
Sarah Lurati ◽  
Sven Krappmann ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cell Lines ◽  
Adoptive Immunotherapy ◽  
Fungal Pathogens ◽  
Fungal Infections ◽  
Multiple Infections ◽  
Target Cells ◽  
Hematopoietic Stem ◽  
T Cell Lines

Abstract Viral and fungal infections remain a leading cause of mortality in patients after hematopoietic stem cell transplantation (HSCT). Adoptive transfer of multipathogen-specific T cells is promising in restoring immunity and thereby preventing and treating infections, but approaches are currently limited because of time-consuming and laborious procedures. Therefore, we investigated a new strategy to simultaneously select T cells specific for viral and fungal pathogens based on activation-dependent expression of CD154. Single- and multipathogen-specific T-cell lines with high specificity for adenovirus (AdV), Epstein-Barr virus (EBV), cytomegalovirus (CMV), Candida albicans, and/or Aspergillus fumigatus could be readily generated within 14 days irrespective of the precursor frequency. The T-cell lines responded reproducibly to endogenously processed antigen and specifically proliferated upon antigenic stimulation. Although isolation based on CD154 favors enrichment of CD4+ T cells, AdV-, EBV- and CMV-specific CD8+ T cells could be expanded and demonstrated lysis of target cells. Conversely, T cell–mediated alloreactivity was almost abrogated compared with the starting fraction. This selection and/or expansion strategy may form the basis for future adoptive immunotherapy trials in patients at risk for multiple infections and may be translated to other antigens.

scholarly journals Toxoflavin Produced byBurkholderia gladiolifromLycoris aureaIs a New Broad-Spectrum Fungicide

2019 ◽  
Vol 85 (9) ◽  
Author(s):  
Xiaodan Li ◽  
Yikui Li ◽  
Ren Wang ◽  
Qizhi Wang ◽  
Ling Lu
Keyword(s):  
Antifungal Activity ◽  
Broad Spectrum ◽  
Fungal Pathogens ◽  
Antifungal Agents ◽  
Fungal Infections ◽  
Endophytic Bacterium ◽  
Content Type ◽  
Burkholderia Gladioli ◽  
Lycoris Aurea ◽  
Resistant Mutants

ABSTRACTFungal infections not only cause extensive agricultural damage but also result in serious diseases in the immunodeficient populations of human beings. Moreover, the increasing emergence of drug resistance has led to a decrease in the efficacy of current antifungals. Thus, screening of new antifungal agents is imperative in the fight against antifungal drug resistance. In this study, we show that an endophytic bacterium,Burkholderia gladioliHDXY-02, isolated from the medicinal plantLycoris aurea, showed broad-spectrum antifungal activity against plant and human fungal pathogens. An antifungal ability assay indicated that the bioactive component was produced from strain HDXY-02 having an extracellular secreted component with a molecular weight lower than 1,000 Da. In addition, we found that this new antifungal could be produced effectively by liquid fermentation of HDXY-02. Furthermore, the purified component contributing to the antifungal activity was identified to be toxoflavin, a yellow compound possessing a pyrimido[5,4-e][1,2,4]triazine ring.In vitrobioactivity studies demonstrated that purified toxoflavin fromB. gladioliHDXY-02 cultures had a significant antifungal activity against the human fungal pathogenAspergillus fumigatus, resulting in abolished germination of conidia. More importantly, the growth inhibition by toxoflavin was observed in both wild-type and drug-resistant mutants (cyp51Aand non-cyp51A) ofA. fumigatus. Finally, an optimized protocol for the large-scale production of toxoflavin (1,533 mg/liter) has been developed. Taken together, our findings provide a promising biosynthetic resource for producing a new antifungal reagent, toxoflavin, from isolates of the endophytic bacteriumB. gladioli.IMPORTANCEHuman fungal infections are a growing problem associated with increased morbidity and mortality. Moreover, a growing number of antifungal-resistant fungal isolates have been reported over the past decade. Thus, the need for novel antifungal agents is imperative. In this study, we show that an endophytic bacterium,Burkholderia gladioli, isolated from the medicinal plantLycoris aurea, is able to abundantly secrete a compound, toxoflavin, which has a strong fungicidal activity not only against plant fungal pathogens but also against human fungal pathogensAspergillus fumigatusandCandida albicans,Cryptococcus neoformans, and the model filamentous fungusAspergillus nidulans. More importantly, toxoflavin also displays an efficacious inhibitory effect against azole antifungal-resistant mutants ofA. fumigatus. Consequently, our findings provide a promising approach to abundantly produce toxoflavin, which has novel broad-spectrum antifungal activity, especially against those currently problematic drug-resistant isolates.

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