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Establishing diagnosis of latent and active histoplasmosis is challenging. Interferon gamma-release assays (IGRAs) may provide evidence of latent and active infection. An enzyme-linked immunospot (ELISpot) assay was developed using yeast cell lysate (YCL) antigen prepared from a representative North American Histoplasma capsulatum strain. Assay parameters were optimized by measuring responses in healthy volunteers with and withoutiHistoplasma/iinfection. Assay performance as an aid for diagnosing histoplasmosis was assessed in a prospective cohort of 88 people with suspected or confirmed infection, and 44 healthy controls enrolled in two centers in North America (2013 to 2018). Antigen specificity of IFN-γ release was demonstrated using ELISpot and enzyme-linked immunosorbent assay (ELISA). Antigen-evoked, single-cell mRNA expression by memory T cells was shown using flow cytometry. The area under the receiver operating characteristic curve (AUC) was estimated at 0.89 (95% confidence interval [CI]: 78.5% to 99.9%). At optimal cutoff, sensitivity was 77.2% (95% CI: 54.6% to 92.2%) and specificity was 100% (95% CI: 89.7% to 100%). Sixteen of 44 healthy volunteers (36.4%) from a region of hyperendemicity had positive responses, suggesting detection of previously unrecognized (latent) infection. The ELISpot assay is sensitive and specific as an aid to diagnose H. capsulatum infection and disease, supporting proof of concept and further development.

A pet cockatoo was the suspected source of

Histoplasmosis is a systemic mycosis caused by the thermally dimorphic fungusiHistoplasma capsulatum/i. Although healthy individuals can develop histoplasmosis, the disease is particularly life-threatening in immunocompromised patients, with a wide range of clinical manifestations depending on the inoculum and virulence of the infecting strain. In this review, we discuss the established virulence factors and pathogenesis traits that makeiH. capsulatum/ihighly adapted to a wide variety of hosts, including mammals. Understanding and integrating these mechanisms is a key step toward devising new preventative and therapeutic interventions.

Aim: Melanin has been linked to pathogenesis in several fungi. They often produce melanin-like pigments in the presence of L-dihydroxyphenylalanine (L-DOPA), but this is poorly studied in Candida glabrata. Methods & materials: C. glabrata was grown in minimal medium with or without L-DOPA supplementation and submitted to a chemical treatment with denaturant and hot acid. Results: C. glabrata turned black when grown in the presence of L-DOPA, whereas cells grown without L-DOPA supplementation remained white. Biophysical properties demonstrated that the pigment was melanin. Melanized C. glabrata cells were effectively protected from azoles and amphotericin B, incubation at 42°C and macrophage killing. Conclusion: In the presence of L-DOPA, C. glabrata produces melanin, increases antifungal resistance and enhances host survival.

Introduction In 2020, we reported the first patient with concomitant COVID-19 and paracoccidioidomycosis (PCM). Since then, no other cases have been recorded in the literature. We aim to update information on the occurrence of COVID-19 in patients with PCM followed at a reference center for infectious diseases at Rio de Janeiro, Brazil. Methods We reviewed the medical records from patients diagnosed with PCM who presented with clinical symptoms, radiological findings, and/or laboratory diagnosis of COVID-19 at any time during their acute or follow-up care. The clinical profiles of these patients were described. Results Between March 2020 and September 2022, we identified six individuals with COVID-19 among the 117 patients with PCM evaluated. The median age was 38 years and the male to female ratio 2:1. Most patients (n = 5) presented for evaluation due to acute PCM. The severity of COVID-19 ranged from mild to severe in acute PCM and only the single patient with chronic PCM died. Conclusions There is a range of disease severity in COVID-19 and PCM co-infection and concomitant disease may represent a severe association, especially in the chronic type of the mycosis with pulmonary involvement. As COVID-19 and chronic PCM share similar clinical aspects and PCM is neglected, it is probable that COVID-19 has been hampering simultaneous PCM diagnosis, which can explain the absence of new co-infection reports. With the continued persistence of COVID-19 globally, these findings further suggest that more attention by providers is necessary to identify co-infections with Paracoccidioides.

Candida aurisis a recently emerged global fungal pathogen, which causes life-threatening infections, often in healthcare settings.C. aurisinfections are worrisome because the fungus is often resistant to multiple antifungal drug classes. Furthermore,C. aurisforms durable and difficult to remove biofilms. Due to the relatively recent, resilient, and resistant nature ofC. auris, we investigated whether it produces the common fungal virulence factor melanin. Melanin is a black-brown pigment typically produced following enzymatic oxidation of aromatic precursors, which promotes fungal virulence through oxidative stress resistance, mammalian immune response evasion, and antifungal peptide and pharmaceutical inactivation. We found that certain strains ofC. aurisoxidized L-DOPA and catecholamines into melanin. Melanization occurred extracellularly in a process mediated by alkalinization of the extracellular environment, resulting in granule-like structures that adhere to the fungus external surface.C. aurishad relatively high cell surface hydrophobicity, but there was no correlation between hydrophobicity and melanization. Melanin protected the fungus from oxidative damage, but we did not observe a protective role during infection of macrophages orGalleria mellonellalarvae. In summary,C. aurisalkalinizes the extracellular medium, which promotes the non-enzymatic oxidation of L-DOPA to melanin that attaches to its surface, thus illustrating a novel mechanism for fungal melanization.

Extracellular vesicles (EVs) are structures released by a variety of cells from all kingdoms of life. EVs are typically involved in communication between tissues and organs, between distinct organisms, or inside microbial communities. The plasticity of these structures is reflected in the range of biological effects they are able to induce or inhibit. The study of fungal EVs is relatively new with the first report in 2007, but investigators have already demonstrated in several model systems that fungal EVs significantly modulate the host immune system and that the immunogenic materials in EV can be harnessed as vaccination platforms. This chapter describes the two main procedures used to isolate EVs from an emerging pathogenic fungus, Candida auris.

With rising skin cancer rates and interest in preventing photoaging, adjuvants for sunscreens are in high demand. The potential of curcumin has been posited due to its anti-inflammatory, antioxidant and wound healing properties. In prior studies, curcumin decreased UV-induced inflammation, apoptotic changes in human keratinocytes and dermal fibroblasts, and the expression of matrix metalloproteinases. However, curcumin's utility has been hindered by poor aqueous solubility and rapid degradation in vivo. To overcome these limitations, we synthesized curcumin nanoparticles (curc-np), which offer sustained topical delivery and enhanced bioavailability. Curc-np and controls were applied to the skin of BALB/c mice prior to UVB irradiation. Twenty-four hours later, mice pre-treated with curc-np showed less erythema, induration and scale compared to controls. Histopathology showed fewer sunburn cells, and TUNEL assay indicated decreased apoptosis in curc-np treated mice. Immunohistochemistry illustrated less p53 expression in skin pre-treated with curc-np. Furthermore, cytokine analysis revealed significantly less IL-6 and significantly greater anti-inflammatory IL-10 in skin of curc-np-treated mice as compared to controls. Taken together, our results reinforce curcumin's established anti-inflammatory effects in the skin and highlight its potential as a photoprotective adjuvant when delivered through nanoparticles. Further investigation alongside sunscreens against UV-induced damage is warranted.

Graphical abstract, Candida auris has emerged as a serious worldwide threat by causing opportunistic infections that are frequently resistant to one or more conventional antifungal medications resulting in high mortality rates. Against this backdrop, health warnings around the world have focused efforts on understanding C. auris fungal biology and effective prevention and treatment approaches to combat this fungus. To date, there is little information about the differentially expressed genes when this fungus is treated with conventional antifungals, and caspofungin is a standard echinocandin deployed in the therapy against C. auris. In this work, we treated two distinct strains of C. auris for 24 h with caspofungin, and the cellular responses were evaluated at the morphological, translational and transcriptional levels. We first observed that the echinocandin caused morphological alterations, aggregation of yeast cells, and modifications in the cell wall composition of C. auris. Transcriptomic analysis revealed an upregulation of genes related to the synthesis of the cell wall, ribosome, and cell cycle after exposure to caspofungin. Supporting these findings, the integrated proteomic analysis showed that caspofungin-treated cells were enriched in ribosome-related proteins and cell wall, especially mannoproteins. Altogether, these results provide further insights into the biology of C. auris and expands our understanding regarding the antifungal activity of caspofungin and reveal cellular targets, as the mannose metabolism, that can be further explored for the development of novel antifungals.

A pet cockatoo was the suspected source of Cryptococcus neoformans recovered from the cerebral spinal fluid (CSF) of an immunocompromised patient with cryptococcosis based on the molecular analyses available in 2000. Here we report whole genome sequence analysis of the clinical and cockatoo strains. Both are closely related MATα strains belonging to the VNII lineage, confirming that the human infection likely originated from pet bird exposure. The two strains differ by 61 single nucleotide polymorphisms, including 8 nonsynonymous changes involving 7 genes. To ascertain whether changes in these genes are selected during mammalian infection, we passaged the cockatoo strain in mice. Remarkably, isolates obtained from mouse tissue possess a frame-shift mutation in one of the seven genes altered in the human sample, a gene predicted to encode a SWI-SNF chromatin-remodeling complex protein. Both cockatoo and patient strains as well as mouse passaged isolates obtained from brain tissue had a premature stop codon in a homolog of ZFC3, a predicted single-zinc finger containing protein, which is associated with larger capsules when deleted and appears to have reverted to a full-length protein in the mouse passaged isolates obtained from lung tissue. The patient strain and mouse passaged isolates show variability in the expression of virulence factors, with differences in capsule size, melanization, and rates on non-lytic expulsion from macrophages observed. Our results establish that environmental strains undergo genomic and phenotypic changes during mammalian passage, suggesting that animal virulence can be a mechanism for genetic change and that the genomes of clinical isolates may provide a readout of mutations acquired during infection.

Methamphetamine (METH) is a major public health and safety problem in the United States. Chronic METH abuse is associated with a 2-fold-higher risk of HIV infection and, possibly, additional infections, particularly those that enter through the respiratory tract or skin. Cryptococcus neoformans is an encapsulated opportunistic yeast-like fungus that is a relatively frequent cause of meningoencephalitis in immunocompromised patients, especially in individuals with AIDS. C. neoformans melanizes during mammalian infection in a process that presumably uses host-supplied compounds such as catecholamines. l-3,4-Dihydroxyphenylalanine (l-Dopa) is a natural catecholamine that is frequently used to induce melanization in C. neoformans. l-Dopa-melanized cryptococci manifest resistance to radiation, phagocytosis, detergents, and heavy metals. Using a systemic mouse model of infection and in vitro assays to critically assess the impact of METH on C. neoformans melanization and pathogenesis, we demonstrated that METH-treated mice infected with melanized yeast cells showed increased fungal burdens in the blood and brain, exacerbating mortality. Interestingly, analyses of cultures of METH-exposed cryptococci supplemented with l-Dopa revealed that METH accelerates fungal melanization, an event of adaptation to external stimuli that can be advantageous to the fungus during pathogenesis. Our findings provide novel evidence of the impact of METH abuse on host homeostasis and increased permissiveness to opportunistic microorganisms.

There is an urgent need to develop novel antifungals. In this study, we screened 1600 compounds for antifungal activity against Cryptococcus neoformans and Candida auris. We evaluated 4 promising compounds against 24 additional isolates of Cr. neoformans, Ca. auris, Cr. deuterogattii, and Cr. gattii. The four compounds, dequalinium chloride (DQC), bleomycin sulfate (BMS), pentamidine isethionate salt (PIS), and clioquinol (CLQ), varied in their efficacy against these pathogens but were generally more effective against cryptococci. The compounds exerted their antifungal effect via multiple mechanisms, including interference with the capsule of cryptococci and induction of hyphal-like morphology in Ca. auris. Our results indicate that DQC, BMS, PIS, and CLQ represent potential prototypes for the future development of antifungals. Lay Summary Fungal infections can be lethal and the options to fight them are scarce. We tested 1600 molecules for their ability to control the growth of two important fungal pathogens, namely Candida auris and species of Cryptococcus. Four of these compounds showed promising antifungal activities.

Replicative aging is an underexplored field of research in medical mycology. Cryptococcus neoformans (Cn) and Candida glabrata (Cg) are dreaded fungal pathogens that cause fatal invasive infections. The fungal cell wall is essential for yeast viability and pathogenesis. In this study, we provide data characterizing age-associated modifications to the cell wall of Cn and Cg. Here, we report that old yeast cells upregulate genes of cell wall biosynthesis, leading to cell wall reorganization, and increased levels of all major components, including glucan, chitin and its derivatives, as well as mannan. This results in a significant thickening of the cell wall in aged cells. Old generation yeast cells exhibited drastic ultrastructural changes, including the presence of abundant vesicle-like particles in the cytoplasm, and enlarged vacuoles with altered pH homeostasis. Our findings suggest that the cell wall modifications could be enabled by augmented intracellular trafficking. This work furthers our understanding of the cell phenotype that emerges during aging. It highlights differences in these two fungal pathogens and elucidates mechanisms that explain the enhanced resistance of old cells to antifungals and phagocytic attacks.IMPORTANCECryptococcus neoformans and Candida glabrata are two opportunistic human fungal pathogens that cause life-threatening diseases. During infection, both microorganisms have the ability to persist for long periods, and treatment failure can occur even if standard testing identifies the yeasts to be sensitive to antifungals. Replicative lifespan is a trait that is measured by the number of divisions a cell undergoes before death. Aging in fungi is associated with enhanced tolerance to antifungals and resistance to phagocytosis, and characterization of old cells may help identify novel antifungal targets. The cell wall remains an attractive target for new therapies because it is essential for fungi and is not present in humans. This study shows that the organization of the fungal cell wall changes remarkably during aging and becomes thicker and is associated with increased intracellular trafficking as well as the alteration of vacuole morphology and pH homeostasis.

Lipids play a fundamental role in fungal cell biology, being essential cell membrane components and major targets of antifungal drugs. A deeper knowledge of lipid metabolism is key for developing new drugs and a better understanding of fungal pathogenesis. Here, we built a comprehensive map of the Histoplasma capsulatum lipid metabolic pathway by incorporating proteomic and lipidomic analyses. We performed genetic complementation and overexpression of H. capsulatum genes in Saccharomyces cerevisiae to validate reactions identified in the map and to determine enzymes responsible for catalyzing orphan reactions. The map led to the identification of both the fatty acid desaturation and the sphingolipid biosynthesis pathways as targets for drug development. We found that the sphingolipid biosynthesis inhibitor myriocin, the fatty acid desaturase inhibitor thiocarlide, and the fatty acid analog 10-thiastearic acid inhibit H. capsulatum growth in nanomolar to low-micromolar concentrations. These compounds also reduced the intracellular infection in an alveolar macrophage cell line. Overall, this lipid metabolic map revealed pathways that can be targeted for drug development. IMPORTANCE It is estimated that 150 people die per hour due to the insufficient therapeutic treatments to combat fungal infections. A major hurdle to developing antifungal therapies is the scarce knowledge on the fungal metabolic pathways and mechanisms of virulence. In this context, fungal lipid metabolism is an excellent candidate for developing drugs due to its essential roles in cellular scaffolds, energy storage, and signaling transductors. Here, we provide a detailed map of Histoplasma capsulatum lipid metabolism. The map revealed points of this fungus lipid metabolism that can be targeted for developing antifungal drugs.

Candida auris is a recently described multidrug-resistant pathogenic fungus that is increasingly responsible for health care-associated outbreaks across the world. Bloodstream infections of this fungus cause death in up to 70% of cases. Aggravating this scenario, the disease-promoting mechanisms of C. auris are poorly understood. Fungi release extracellular vesicles (EVs) that carry a broad range of molecules, including proteins, lipids, carbohydrates, pigments, and RNA, many of which are virulence factors. Here, we carried out a comparative molecular characterization of C. auris and Candida albicans EVs and evaluated their capacity to modulate effector mechanisms of host immune defense. Using proteomics, lipidomics, and transcriptomics, we found that C. auris released EVs with payloads that were significantly different from those of EVs released by C. albicans. EVs released by C. auris potentiated the adhesion of this yeast to an epithelial cell monolayer, while EVs from C. albicans had no effect. C. albicans EVs primed macrophages for enhanced intracellular yeast killing, whereas C. auris EVs promoted survival of the fungal cells. Moreover, EVs from both C. auris and C. albicans induced the activation of bone marrow-derived dendritic cells. Together, our findings show distinct profiles and properties of EVs released by C. auris and by C. albicans and highlight the potential contribution of C. auris EVs to the pathogenesis of this emerging pathogen. IMPORTANCECandida auris is a recently described multidrug-resistant pathogenic fungus that is responsible for outbreaks across the globe, particularly in the context of nosocomial infections. Its virulence factors and pathogenesis are poorly understood. Here, we tested the hypothesis that extracellular vesicles (EVs) released by C. auris are a disease-promoting factor. We describe the production of EVs by C. auris and compare their biological activities against those of the better-characterized EVs from C. albicans. C. auris EVs have immunoregulatory properties, of which some are opposite those of C. albicans EVs. We also explored the cargo and structural components of those vesicles and found that they are remarkably distinct compared to EVs from C. auris’s phylogenetic relative Candida albicans.

Lipid microdomains or lipid rafts are dynamic and tightly ordered regions of the plasma membrane. In mammalian cells, they are enriched in cholesterol, glycosphingolipids, Glycosylphosphatidylinositol-anchored and signalling-related proteins. Several studies have suggested that mammalian pattern recognition receptors are concentrated or recruited to lipid domains during host-pathogen association to enhance the effectiveness of host effector processes. However, pathogens have also evolved strategies to exploit these domains to invade cells and survive. In fungal organisms, a complex cell wall network usually mediates the first contact with the host cells. This cell wall may contain virulence factors that interfere with the host membrane microdomains dynamics, potentially impacting the infection outcome. Indeed, the microdomain disruption can dampen fungus-host cell adhesion, phagocytosis and cellular immune responses. Here, we provide an overview of regulatory strategies employed by pathogenic fungi to engage with and potentially subvert the lipid microdomains of host cells. TAKE AWAY: Lipid microdomains are ordered regions of the plasma membrane enriched in cholesterol, glycosphingolipids (GSL), GPI-anchored and signalling-related proteins. Pathogen recognition by host immune cells can involve lipid microdomain participation. During this process, these domains can coalesce in larger complexes recruiting receptors and signalling proteins, significantly increasing their signalling abilities. The antifungal innate immune response is mediated by the engagement of pathogen-associated molecular patterns to pattern recognition receptors (PRRs) at the plasma membrane of innate immune cells. Lipid microdomains can concentrate or recruit PRRs during host cell-fungi association through a multi-interactive mechanism. This association can enhance the effectiveness of host effector processes. However, virulence factors at the fungal cell surface and extracellular vesicles can re-assembly these domains, compromising the downstream signalling and favouring the disease development. Lipid microdomains are therefore very attractive targets for novel drugs to combat fungal infections.

Melanins are one of the great natural pigments produced by a wide variety of fungal species that promote fitness and cell survival in diverse hostile environments, including during mammalian infection. In this study, we sought to demonstrate the production of melanin in the conidia and hyphae of saprophytic fungi, including dematiaceous and hyaline fungi. We showed that a melanin-specific monoclonal antibody (MAb) avidly labeled the cell walls of hyphae and conidia, consistent with the presence of melanin in these structures, in 14 diverse fungal species. The conidia of saprophytic fungi were treated with proteolytic enzymes, denaturant, and concentrated hot acid to yield dark particles, which were shown to be stable free radicals, consistent with their identification as melanins. Samples obtained from patients with fungal keratitis due to Fusarium falciforme, Aspergillus fumigatus, Aspergillus flavus, Curvularia lunata, Exserohilum rostratum, or Fonsecaea pedrosoi were found to be intensely labeled by the melanin-specific MAb at the fungal hyphal cell walls. These results support the hypothesis that melanin is a common component that promotes survival under harsh conditions and facilitates fungal virulence. Increased understanding of the processes of melanization and the development of methods to interfere with pigment formation may lead to novel approaches to combat these complex pathogens that are associated with high rates of morbidity and mortality.

Publisher Copyright: Copyright © 2021 Horváth et al. Oral epithelial cells monitor microbiome composition and initiate immune response upon dysbiosis, as in the case of Candida imbalances. Candida species, such as C. albicans and C. parapsilosis, are the most prevalent yeasts in the oral cavity. Comparison of healthy oral epithelial cell responses revealed that while C. albicans infection robustly activated inflammation cascades, C. parapsilosis primarily activated various inflammation-independent pathways. In posttranscriptional regulatory processes, several miRNAs were altered by both species. For C. parapsilosis, the dose of yeast cells directly correlated with changes in transcriptomic responses with higher fungal burdens inducing significantly different and broader changes. MicroRNAs (miRNAs) associated with carbohydrate metabolism-, hypoxia-, and vascular development-related responses dominated with C. parapsilosis infection, whereas C. albicans altered miRNAs linked to inflammatory responses. Subsequent analyses of hypoxia-inducible factor 1a (HIF1-a) and hepatic stellate cell (HSC) activation pathways predicted target genes through which miRNA-dependent regulation of yeast-specific functions may occur, which also supported the observed species-specific responses. Our findings suggest that C. parapsilosis is recognized as a commensal at low doses by the oral epithelium; however, increased fungal burden activates different pathways, some of which overlap with the inflammatory processes robustly induced by C. albicans. IMPORTANCE A relatively new topic within the field of immunology involves the role of miRNAs in innate as well as adaptive immune response regulation. In recent years, posttranscriptional regulation of host-pathogenic fungal interactions through miRNAs was also suggested. Our study reveals that the distinct nature of human oral epithelial cell responses toward C. parapsilosis and C. albicans is possibly due to species-specific fine-tuning of host miRNA regulatory processes. The findings of this study also shed new light on the nature of early host cell transcriptional responses to the presence of C. parapsilosis and highlight the species’ potential inflammation-independent host activation processes. These findings contribute to our better understanding of how miRNA deregulation at the oral immunological barrier, in non-canonical immune cells, may discriminate between fungal species, particularly Candida species with high or low pathogenic potential.

Talaromyces marneffei is a thermally dimorphic fungus that causes opportunistic systemic mycoses in patients with AIDS or other immunodeficiency syndromes. The purpose of this study was to develop an immunochromatographic strip test (ICT) based on a solid phase sandwich format immunoassay for the detection of T. marneffei antigens in clinical urine specimens. The T. marneffei yeast phase specific monoclonal antibody 4D1 (MAb4D1) conjugated with colloidal gold nanoparticle was used as a specific signal reporter. Galanthus nivalis Agglutinin (GNA) was adsorbed onto nitrocellulose membrane to serve as the test line. Similarly, a control line was created above the test line by immobilization of rabbit anti-mouse IgG. The immobilized GNA served as capturing molecule and as non-immune mediated anti-terminal mannose of T. marneffei antigenic mannoprotein. The MAb4D1–GNA based ICT showed specific binding activity with yeast phase antigen of T. marneffei, and it did not react with other common pathogenic fungal antigens. The limit of detection of this ICT for T. marneffei antigen spiked in normal urine was approximately 0.6 μg/ml. The diagnostic performance of the ICT was validated using 341 urine samples from patents with culture- confirmed T. marneffei infection and from a control group of healthy individuals and patients with other infections in an endemic area. The ICT exhibited 89.47% sensitivity, 100% specificity, and 97.65% accuracy. Our results demonstrate that the urine-based GNA–MAb4D1 based ICT produces a visual result within 30 minutes and that the test is highly specific for the diagnosis of T. marneffei infection. The findings validate the deployment of the ICT for clinical use., Author summary Talaromycosis (Penicilliosis marneffei) is a neglected disease that causes an opportunistic systemic mycoses in AIDS and other immune-deficient patients living in Southeast Asia, China and the Indian subcontinent. Although laboratory culture remains a gold standard diagnostic method, it lacks sensitivity and is time-consuming, which results in delayed patient’s treatment and needed care. In this study, we develop an immunochromatographic strip test (ICT) by utilizing a yeast phase specific monoclonal antibody 4D1 and Galanthus nivalis agglutinin for detection of T. marneffei antigens in clinical urine specimens. Our data showed that the assay exhibited high sensitivity (89.47%) and specificity (100%), with its result available within 30 minutes. In addition, this diagnostic assay is inexpensive, reproducible, and simple to perform. Therefore, the T. marneffei ICT should be considered for clinical application in the context of rapid and affordable point-of-care diagnostic test to reduce the burden of talaromycosis mortality in patients in low resource countries.

The aim of this study was to develop a novel lateral flow immunochromatoghaphic strip test (ICT) for detecting cryptococcal polysaccharide capsular antigens using only a single specific monoclonal antibody, mAb 18B7. The mAb 18B7 is a well characterized antibody that specifically binds repeating epitopes displayed on the cryptococcal polysaccharide glucuronoxylomannan (GXM). We validated the immunoreactivities of mAb 18B7 against capsular antigens of different cryptococcal serotypes. The mAb 18B7 ICT was constructed as a sandwich ICT strip and the antibody serving in the mobile phase (colloidal gold conjugated mAb 18B7) to bind one of the GXM epitopes while the stationary phase antibody (immobilized mAb18B7 on test line) binding to other remaining unoccupied epitopes to generate a positive visual readout. The lower limit of detection of capsular antigens for each of the Cryptococcus serotypes tested was 0.63 ng/mL. No cross-reaction was found against a panel of antigens isolated from cultures of other pathogenic fungal, except the crude antigen of Trichosporon sp. with the lower limit of detection of 500 ng/mL (~800 times higher than that for cryptococcal GXM). The performance of the mAb 18B7 ICT strip was studied using cerebrospinal fluid (CSF) and serum and compared to commercial diagnostic kits (latex agglutination CALAS and CrAg IMMY). The sensitivity, specificity and accuracy of the mAb18B7 ICT with CSF from patients with confirmed cryptococcal meningitis were 92.86%, 100% and 96.23%, respectively. No false positives were observed with samples from non-cryptococcosis patients. With serum samples, the mAb 18B7 ICT gave a sensitivity, specificity and accuracy of 96.15%, 97.78% and 96.91%, respectively. Our results show that the mAb 18B7 based ICT was reliable, reproducible, and cost-effective as a point-of-care immunodiagnostic test for cryptococcosis. The mAb 18B7 ICT may be particularly useful in countries where commercial kits are not available or affordable.

Heat shock proteins (Hsps) are highly conserved molecules that are constitutively expressed and upregulated in response to physiological stress conditions. These immunogenic chaperones can have essential functions in fungi, particularly in dimorphic pathogens. Histoplasma capsulatum and Paracoccidioides species are dimorphic fungi that are the causative agents of histoplasmosis and paracoccidioidomycosis, respectively, which are systemic mycoses with significant rates of morbidity and mortality. Current treatment consists of long-term antifungal agents, and there is an urgent need for new therapeutic approaches with higher efficacy, lower toxicity, better biodistribution and improved selectivity. We engineered an immunoglobulin G1 (IgG1) isotype chimeric mouse-human monoclonal antibody, titled ch-MAb 4E12, from the parental IgG2a MAb 4E12, a monoclonal antibody to H. capsulatum Hsp60 that is protective in experimental histoplasmosis and paracoccidioidomycosis models elicited by H. capsulatum var. capsulatum and Paracoccidioides lutzii, respectively. The ch-MAb 4E12 increased phagolysosomal fusion and enhanced the yeasts uptake by PMA differentiated human THP1 macrophage cells in vitro. At low concentrations, the chimeric antibody significantly reduced the pulmonary and splenic fungal burden compared to an irrelevant antibody or no treatment. These results are the first to show that a chimeric mouse-human antibody can modify infection caused by dimorphic fungi.

Oral squamous cell carcinoma (OSCC) is a serious health issue worldwide. OSCC is highly associated with oral candidiasis, although it is unclear whether the fungus promotes the genesis and progression of OSCC or cancer facilitates the growth of the fungus. Therefore, we investigated whether Candida could directly influence OSCC development and progression. Our in vitro results suggest that the presence of live C. albicans, but not C. parapsilosis, enhances the progression of OSCC by stimulating the production of matrix metalloproteinases, oncometabolites, pro-tumor signaling routes, and overexpression of prognostic marker genes associated with metastatic events. We also found that oral candidiasis triggered by C. albicans enhanced the progression of OSCC in vivo through the induction of inflammation and overexpression of metastatic genes and markers of epithelial-mesenchymal transition. Taken together, these results suggest that C. albicans actively participates in the complex process of OSCC progression.

The prevalence of fungal infections has increased in immunocompromised patients, leading to millions of deaths annually. Arachidonic acid (AA) metabolites, such as eicosanoids, play important roles in regulating innate and adaptative immune function, particularly since they can function as virulence factors enhancing fungal colonization and are produced by mammalian and lower eukaryotes, such as yeasts and other fungi (Candida albicans, Histoplasma capsulatum and Cryptococcus neoformans). C. albicans produces prostaglandins (PG), Leukotrienes (LT) and Resolvins (Rvs), whereas the first two have been well documented in Cryptococcus sp. and H. capsulatum. In this review, we cover the eicosanoids produced by the host and fungi during fungal infections. These fungal-derived PGs have immunomodulatory functions analogous to their mammalian counterparts. Prostaglandin E2 (PGE2) protects C. albicans and C. parapsilosis cells from the phagocytic and killing activity of macrophages. H. capsulatum PGs augment the fungal burden and host mortality rates in histoplasmosis. However, PGD2 potentiates the effects and production of LTB4, which is a very potent neutrophil chemoattractant that enhances host responses. Altogether, these data suggest that eicosanoids, mainly PGE2, may serve as a new potential target to combat diverse fungal infections.