epiglucan and Cryptococcosis

Except for cryptococcosis, fungal infection of the central nervous system (FI-CNS) is a rare but severe complication. Clinical and radiological signs are non-specific, and the value of conventional mycological diagnosis is very low. This study aimed to assess the value of β1,3-D-glucan (BDG) detection in the cerebrospinal fluid (CSF) of non-neonatal non-cryptococcosis patients.. Cases associated with BDG assay in the CSF performed in 3 French University Hospitals over 5 years were included. Clinical, radiological, and mycological results were used to classify the episodes as proven/highly probable, probable, excluded, and unclassified FI-CNS. Sensitivity and specificity were compared to that calculated from an exhaustive review of the literature.. In total, 228 episodes consisting of 4, 7, 177, and 40 proven/highly probable, probable, excluded, and unclassified FI-CNS, respectively, were analysed. The sensitivity of BDG assay in CSF to diagnose proven/highly probable/probable FI-CNS ranged from 72.7% [95% confidence interval {CI}: 43.4%‒90.2%] to 100% [95% CI: 51%‒100%] in our study and was 82% in the literature. For the first time, specificity could be calculated over a large panel of pertinent controls and was found at 81.8% [95% CI: 75.3%‒86.8%]. Bacterial neurologic infections were associated with several false positive results.. Despite its sub-optimal performance, BDG assay in the CSF should be added to the diagnostic armamentarium for FI-CNS.

Topics: beta-Glucans; Central Nervous System; Cryptococcosis; Glucans; Humans; Multicenter Studies as Topic; Retrospective Studies; Sensitivity and Specificity

Fungal infections are of great relevance in surgical intensive care and Candida species represent the predominant part of fungal pathogens. Invasive aspergillosis is also relevant especially in patients with chronic pulmonary diseases. It is crucial for therapy success to begin adequate antifungal treatment at an early stage of the disease. Risk stratification of individual patient symptoms is essential for therapy timing. In case of suspected or proven candida infection, fluconazole is the agent of choice when the patient is clinically stable and no azoles have been administrated in advance and the local epidemiology makes azol resistance unlikely. For clinically instable patients with organ dysfunction the echinocandins serve as primary therapy because of their broad spectrum and reasonable safety profile. Due to a relevant proportion of azole resistant Candida species, susceptibility testing should be done routinely. Depending on the species detected de-escalating to an azole is feasible if organ dysfunctions have resolved. An invasive aspergillosis is primarily treated with voriconazole.

Topics: Adjuvants, Immunologic; Antifungal Agents; Azoles; beta-Glucans; Candidiasis; Critical Care; Cryptococcosis; Echinocandins; Galactose; Humans; Mannans; Mucus; Mycoses; Polyenes; Reverse Transcriptase Polymerase Chain Reaction; Risk Assessment; Tomography, X-Ray Computed

Topics: Antigens, Fungal; beta-Glucans; Biomarkers; Cryptococcosis; Cryptococcus neoformans; Humans; Latex Fixation Tests; Proteoglycans

Cryptococcosis is definitely diagnosed microbiologically or pathologically. As adjunctive diagnosis, serological and genetic diagnosis could be a promising method for rapid diagnosis of cryptococcosis. Capsular polysaccharides such as glucuronoxylomannan were used as antigens for serodiagnosis and very high sensitivity and specificity were obtained in pulmonar cryptococcosis. Polymerase chain reaction for URA5 gene was examined but the sensitivity was not high enough for clinical use.

Topics: Animals; beta-Glucans; Cryptococcosis; Cryptococcus; Glucans; Humans; Lung Diseases, Fungal; Polymerase Chain Reaction; Polysaccharides; Sensitivity and Specificity; Serologic Tests

(1-->3)-beta-D-Glucan is one of the major structural components of fungi, and it seems that it can be detected by the fractionated (1-->3)-beta-D-glucan-sensitive component from a Limulus lysate, factor G. We evaluated the concentration of (1-->3)-beta-D-glucan by using factor G and other fungal antigens in 24 patients with clinical evidence of mycosis and 36 healthy subjects. The mean concentration of (1-->3)-beta-D-glucan in the plasma of the healthy subjects was found to be 2.7 +/- 1.9 pg/ml (range, < 6.9 pg/ml), and it was found to be substantially higher in all 11 patients with candidemia (mean, 2,207.4 pg/ml; range, 325.4 to 8,449.0 pg/ml). Eight of those 11 patients with candidemia (73%) were positive for the Cand-Tec heat-labile candida antigen and only 3 patients (27%) were positive for mannan antigen. Three patients with invasive pulmonary aspergillosis were positive for galactomannan and had, in addition, high concentrations of (1-->3)-beta-D-glucan (mean, 323.3 pg/ml; range, 27.0 to 894.0 pg/ml). All 10 patients with cryptococcosis (including 2 patients with probable cryptococcosis) were positive for cryptococcal antigen by the Eiken latex test; however, (1-->3)-beta-D-glucan levels were not elevated in these patients (mean, 7.0 pg/ml; range, < 16.5 pg/ml). Our results indicated that (1-->3)-beta-D-glucan levels are elevated in patients with candidiasis and aspergillosis but not in those with cryptococcosis.

Topics: Adult; Antigens, Fungal; Aspergillosis; beta-Glucans; Candidiasis; Cryptococcosis; Female; Fungemia; Galactose; Glucans; Humans; Limulus Test; Male; Mannans; Middle Aged; Serologic Tests

Current antifungal drugs present poor effectiveness and there is no available vaccine for fungal infections. Thus, novel strategies to treat or prevent invasive mycosis, such as cryptococcosis, are highly desirable. One strategy is the use of immunomodulators of polysaccharide nature isolated from mushrooms. The purpose of the present work was to evaluate the immunostimulatory activity of β-(1,3)-glucan-containing exopolysaccharides (EPS) from the edible mushrooms Auricularia auricula in phagocytes and mice infected with Cryptococcus neoformans. EPS triggered macrophages and dendritic cell activation upon binding to Dectin-1, a pattern recognition receptor of the C-type lectin receptor family. Engagement of Dectin-1 culminated in pro-inflammatory cytokine production and cell maturation via its canonical Syk-dependent pathway signaling. Furthermore, upon EPS treatment, M2-like phenotype macrophages, known to support intracellular survival and replication of C. neoformans, repolarize to M1 macrophage pattern associated with enhanced production of the microbicidal molecule nitric oxide that results in efficient killing of C. neoformans. Treatment with EPS also upregulated transcript levels of genes encoding products associated with host protection against C. neoformans and Dectin-1 mediated signaling in macrophages. Finally, orally administrated β-glucan-containing EPS from A. auricular enhanced the survival of mice infected with C. neoformans. In conclusion, the results demonstrate that EPS from A. auricula exert immunostimulatory activity in phagocytes and induce host protection against C. neoformans, suggesting that polysaccharides from this mushroom may be promising as an adjuvant for vaccines or antifungal therapy.

Topics: Agaricales; Animals; beta-Glucans; Cryptococcosis; Cryptococcus neoformans; Cytokines; Dendritic Cells; Fungal Polysaccharides; Immunologic Factors; Lectins, C-Type; Lung Diseases, Fungal; Macrophages; Mice; Mice, Inbred C57BL; Phagocytes; Signal Transduction

The human fungal pathogen, Cryptococcus neoformans, dramatically alters its cell wall, both in size and composition, upon entering the host. This cell wall remodeling is essential for host immune avoidance by this pathogen. In a genetic screen for mutants with changes in their cell wall, we identified a novel protein, Mar1, that controls cell wall organization and immune evasion. Through phenotypic studies of a loss-of-function strain, we have demonstrated that the mar1Δ mutant has an aberrant cell surface and a defect in polysaccharide capsule attachment, resulting in attenuated virulence. Furthermore, the mar1Δ mutant displays increased staining for exposed cell wall chitin and chitosan when the cells are grown in host-like tissue culture conditions. However, HPLC analysis of whole cell walls and RT-PCR analysis of cell wall synthase genes demonstrated that this increased chitin exposure is likely due to decreased levels of glucans and mannans in the outer cell wall layers. We observed that the Mar1 protein differentially localizes to cellular membranes in a condition dependent manner, and we have further shown that the mar1Δ mutant displays defects in intracellular trafficking, resulting in a mislocalization of the β-glucan synthase catalytic subunit, Fks1. These cell surface changes influence the host-pathogen interaction, resulting in increased macrophage activation to microbial challenge in vitro. We established that several host innate immune signaling proteins are required for the observed macrophage activation, including the Card9 and MyD88 adaptor proteins, as well as the Dectin-1 and TLR2 pattern recognition receptors. These studies explore novel mechanisms by which a microbial pathogen regulates its cell surface in response to the host, as well as how dysregulation of this adaptive response leads to defective immune avoidance.

Topics: Animals; beta-Glucans; Cell Wall; Cells, Cultured; Cryptococcosis; Cryptococcus neoformans; Dendritic Cells; Female; Fungal Proteins; Host-Pathogen Interactions; Humans; Immune Evasion; Macrophages; Male; Mice; Mice, Inbred BALB C; Mice, Inbred C57BL; Protein Transport; Receptors, Pattern Recognition

Infection by invasive fungi, such as

Topics: Animals; Aspergillosis; Aspergillus fumigatus; B-Lymphocytes; beta-Glucans; Candida albicans; Candidiasis; Cryptococcosis; Cryptococcus neoformans; Immunity, Innate; Mannans; Mice; Mice, Inbred C57BL; Mice, Knockout; NF-kappa B; Polysaccharides; RAW 264.7 Cells; Receptors, IgE; Receptors, Pattern Recognition; Signal Transduction

Topics: Aged; Antifungal Agents; beta-Glucans; Cryptococcosis; Diagnostic Errors; Echinocandins; Fatal Outcome; Female; Humans; Immunocompromised Host; Lipopeptides; Micafungin; Pneumonia, Pneumocystis; Purpura Fulminans; Tomography, X-Ray Computed

The polysaccharide beta-1,6-glucan is a major component of the cell wall of Cryptococcus neoformans, but its function has not been investigated in this fungal pathogen. We have identified and characterized seven genes, belonging to the KRE family, which are putatively involved in beta-1,6-glucan synthesis. The H99 deletion mutants kre5Delta and kre6Deltaskn1Delta contained less cell wall beta-1,6-glucan, grew slowly with an aberrant morphology, were highly sensitive to environmental and chemical stress and were avirulent in a mouse inhalation model of infection. These two mutants displayed alterations in cell wall chitosan and the exopolysaccharide capsule, a primary cryptococcal virulence determinant. The cell wall content of the GPI-anchored phospholipase B1 (Plb1) enzyme, which is required for cryptococcal cell wall integrity and virulence, was reduced in kre5Delta and kre6Deltaskn1Delta. Our results indicate that KRE5, KRE6 and SKN1 are involved in beta-1,6-glucan synthesis, maintenance of cell wall integrity and retention of mannoproteins and known cryptococcal virulence factors in the cell wall of C. neoformans. This study sets the stage for future investigations into the function of this abundant cell wall polymer.

Topics: Animals; Architecture; beta-Glucans; Cell Wall; Cryptococcosis; Cryptococcus neoformans; Disease Models, Animal; Fungal Proteins; Gene Deletion; Maintenance; Mice; Polysaccharides; Protein Binding; Survival Analysis; Virulence

The cell walls of all medically important fungi contain a unique polyglucose compound, beta(1-3) glucan. In the present study, murine monoclonal antibodies were produced against linear and beta(1-6) branched beta(1-3) glucans, and their specificities were characterized for reactivity to other beta glucans, fungal cell wall fragments, and fungal cells. Their reactivity was also compared with that of rabbit polyclonal antibodies raised against the same immunogens. Two mouse monoclonal antibodies (AG and BG) recognized immunoreactive epitopes in beta(1-3)(1-6) glucan by ELISA. In an inhibition assay of the anti-beta(1-3)(1-6) activity of the monoclonals, the homologous antigen effectively inhibited the activity as expected, while beta(1-3) also inhibited the assay but to a much lesser extent. No inhibition was obtained by beta(1-3)(1-4) or beta(1-6), while a cell wall extract of Candida albicans (PPM) effectively inhibited both monoclonals. Cell wall fragments of C. albicans (CaCW) and Cryptococcus neoformans (CnCW) inhibited the anti-beta(1-3)(1-6) activity of AG, while BG was much less or not inhibited at all. Immunofluorescence confirmed the unique antibody specificity of AG by its recognition of a beta(1-3)(1-6)-associated epitope on the cell surfaces of C. albicans,C. krusei, C. glabrata, and nonencapsulated C. neoformans. The epitope for the AG antibody is suggested to be present in the branching point of beta(1-3)(1-6), or in the randomly coiled beta(1-3) polyglucan due to the presence of branches. Thus, monoclonal antibodies to beta(1-3)(1-6) glucans may have potential as tools in the laboratory diagnosis of invasive yeast infections.

Topics: Animals; Antibodies, Fungal; Antibodies, Monoclonal; Antibody Specificity; Antigens, Fungal; beta-Glucans; Candida albicans; Candidiasis; Cell Wall; Cross Reactions; Cryptococcosis; Cryptococcus neoformans; Enzyme-Linked Immunosorbent Assay; Epitopes; Female; Fluorescent Antibody Technique; Immune Sera; Mice; Mice, Inbred BALB C; Rabbits

In this study we tested the in vitro and in vivo anti-Cryptococcus neoformans activity of an antilaminarin (anti-beta-glucan) monoclonal antibody (MAb 2G8) (immunoglobulin G2b) which was previously shown to inhibit the growth of beta-glucan-exposing Candida albicans cells. Here we show that MAb 2G8 binds to the cell wall of C. neoformans and inhibits its growth to an extent comparable to that observed for C. albicans. Binding and growth inhibition were detected almost equally for encapsulated and acapsular C. neoformans strains. In addition, at subinhibitory concentrations, MAb 2G8 reduced the capsule thickness without affecting protease or phospholipase production. Acapsular fungal cells, but not encapsulated fungal cells, were opsonized by the antibody and more efficiently phagocytosed and killed by human monocytes and by murine peritoneal macrophages. A single administration of MAb 2G8 resulted in a reduction in the fungal burden in the brains and livers of mice systemically infected with a highly virulent, encapsulated C. neoformans strain. This protective effect was also detected in neutropenic mice. Overall, these findings demonstrate that cell wall beta-glucan of encapsulated C. neoformans is accessible to antibodies which can exert remarkable anticryptococcal activities in vitro and in vivo.

Topics: Animals; Antibodies, Fungal; Antibodies, Monoclonal; beta-Glucans; Brain; Cell Wall; Cells, Cultured; Colony Count, Microbial; Cryptococcosis; Cryptococcus neoformans; Female; Glucans; Humans; Immunotherapy; Liver; Macrophages; Mice; Mice, Inbred BALB C; Monocytes; Phagocytosis; Polysaccharides; Protein Binding

An engineered, killer decapeptide (KP) has been synthesized based on the sequence of a recombinant, single-chain anti-idiotypic antibody (KT-scFv) acting as a functional internal image of a yeast killer toxin. Killer decapeptide exerted a strong fungicidal activity against Candida albicans, which was attributed to peptide interaction with beta-glucan. As this polysaccharide is also a critical component of the cryptococcal cell wall, we wondered whether KP was also active against Cryptococcus neoformans, a human pathogen of increasing medical importance. We found that KP was able to kill both capsular and acapsular C. neoformans cells in vitro. Furthermore, KP impaired the production of specific C. neoformans virulence factors including protease and urease activity and capsule formation, rendering the fungus more susceptible to natural effector cells. In vivo treatment with KP significantly reduced fungal burden in mice with cryptococcosis and, importantly, protected the majority of immunosuppressed animals from an otherwise lethal infection. Given the relevance of cryptococcosis in immunocompromised individuals and the inability of conventional drugs to completely resolve the infection, the results of the present study indicate KP as an ideal candidate for further studies on novel anticryptococcal agents.

Topics: Animals; Antifungal Agents; beta-Glucans; Candida albicans; Cryptococcosis; Cryptococcus neoformans; Dose-Response Relationship, Drug; Female; Glucans; Humans; Macrophages; Melanins; Mice; Mice, Inbred BALB C; Neutrophils; Peptides; Polysaccharides; Survival Rate; Virulence Factors

The present multicentre clinical study was conducted to assess the clinical utility of a new diagnostic method for deep mycosis in which (1-->3)-beta-D-glucan, a fungal cell wall component existing in plasma, was quantitatively measured by the kinetic turbidimetric Limulus test (WB003). Plasma (1-->3)-beta-D-glucan concentrations were 0.57 +/- 0.10 microgram/l in 92 healthy subjects and 0.62 +/- 0.32 microgram/l in 26 patients with non-mycotic diseases (disease control group). In comparison with these healthy subjects and patients with non-mycotic diseases, patients with mycosis had significantly higher plasma (1-->3)-beta-D-glucan concentrations: 19.63 +/- 73.28 micrograms/l in 12 patients with candidaemia, 11.28 +/- 21.42 micrograms/l in 7 patients with urinary Candida infection, 4.84 +/- 12.71 micrograms/l in 5 patients with pulmonary candidiasis, and 12.21 +/- 31.31 micrograms/l in 4 patients with invasive pulmonary aspergillosis. On the statistical analysis of these data, a cut-off value was set at 1.0 microgram/l. Using this cut-off value, 3 patients with pulmonary cryptococcosis and 4 patients (4/6) with pulmonary aspergilloma were all negative with low plasma (1-->3-beta-D-glucan levels. The test WB003 provided equivalent or higher efficiency of diagnosis of candidiasis and aspergillosis, in comparison with commercially available antigen detection kits, demonstrating its utility as a diagnostic reagent. It may also be useful in assessing therapeutic effectiveness when used periodically after treatment.

Topics: Adolescent; Adult; Aged; Aged, 80 and over; Aspergillosis; beta-Glucans; Candidiasis; Cryptococcosis; Diagnostic Errors; Evaluation Studies as Topic; Female; Fungemia; Glucans; Humans; Kinetics; Limulus Test; Lung Diseases, Fungal; Male; Middle Aged; Mycoses; Nephelometry and Turbidimetry; Time Factors; Urinary Tract Infections

(1-3)-beta-D-Glucan (beta-glucan) is a major structural component of fungi. The G test is a direct method to detect beta-glucan using fractionated (1-3)-beta-D-glucan-sensitive component, factor G, eluted from the limulus lysate. Previously, we reported that the G test is a more sensitive method than the mannan detection assay for the serological diagnosis of Candida infection. In this study, we discuss beta-glucanemia in patients with pulmonary aspergillosis and cryptococcosis. The concentration of beta-glucan was less than 10 pg/ml in 9 of 10 cases of pulmonary cryptococcosis, except for one case receiving hemodialysis (16.5 pg/ml). beta-Glucan increased in 3 cases of invasive pulmonary aspergillosis (27-937 pg/ml). Galactomannan antigen was positive in all of those cases. In 8 cases of aspergilloma, which showed fungus ball on roentgenogram, the mean concentration of beta-glucan was 67.1 +/- 92.7 pg/ml. Two of 8 cases were positive for galactomannan antigen. One of three cases of PAIC (productive aspergilloma on the inner wall of a cavity) and one case of chronic necrotizing pulmonary aspergillosis showed slightly increased levels of beta-glucan and positive results of galactomannan antigen test.

Topics: Adult; Aged; Antigens, Fungal; Aspergillosis; beta-Glucans; Child; Cryptococcosis; Female; Galactose; Glucans; Humans; Lung Diseases, Fungal; Male; Mannans; Middle Aged