T-cell Subsets and Antifungal Host Defenses

Candida albicans: the current status regarding vaginal infections

Vaginal infections caused by Candida albicans are a significant global health concern due to their recurrence and negative impact on quality of life. This review examines the pathogenesis of C. albicans infections, emphasizing critical virulence factors such as biofilm formation, adherence, and phenotypic switching. Risk factors include immune system suppression, antibiotic use, and hormonal changes, all of which can lead to fungal overgrowth and infection. Current prevention and/or treatment strategies primarily rely on antifungal therapies, personal hygiene practices, and probiotics. However, challenges like antifungal resistance, recurrence, and limited treatment efficacy highlight the need for innovative approaches. Therefore, emerging methods such as novel antifungal agents, vaccines, and nanotechnology-based delivery systems offer promising advancements to improve infection control. Additionally, the immune system plays a key role in preventing C. albicans infections, with both innate and adaptive immunity acting to restrict fungal colonization and growth. Commercially available products, such as antifungal creams, vaginal probiotics, and hygiene solutions, are practical options but often lack long-term efficacy. Persistent challenges, including resistance, patient noncompliance, and restricted access to emerging therapies, hinder comprehensive prevention and treatment efforts. Thus, future research should focus on promoting interdisciplinary approaches, integrating personalized medicine, and enhancing healthcare accessibility. This review intends to present the current state of the art within the abovementioned issues and to enhance the understanding of the multifactorial nature of C. albicans infections and advanced prevention strategies, which are essential to reduce the burden of vaginal candidiasis worldwide and improve patient quality of life outcomes. KEY POINTS: • Candida albicans pathogenesis involves biofilms, adherence, and phenotypic switching. • Vaccines, nanotechnology, and new drugs offer improved prevention and treatment. • Addressing antifungal resistance and patient compliance is key for prevention success.

Extracellular Vesicles from Dendritic Cells Protect Against Sporothrix brasiliensis Yeast Cells

Sporotrichosis is an emerging subcutaneous mycotic zoonosis that affects the skin, lymphatic system, and other organs of humans and animals. Like other infectious fungal diseases, it becomes even more severe when it affects immunosuppressed patients. This infection has a global distribution and is endemic in some regions of Brazil and it is an important zoonotic public health problem. The disease is caused by a complex of at least four pathogenic species, including Sporothrix brasiliensis. The immunological response against these species has not yet been completely elucidated. Still, structures such as extracellular vesicles could carry important components that can contribute to the modulation and control of this significant infection. Thus, this work aims to analyze the participation of EVs from naïve dendritic cells and EVs from DCs previously primed with S. brasiliensis yeast and primed with EVs from the fungus in the immune response against experimental sporotrichosis in murine models. The groups that received EVs from DCs primed with S. brasiliensis or their EVs showed a significant decrease in fungal load compared to the negative control group. When we analyzed the cytokine profile in the skin of mice treated with EVs before infection, we observed an increase in IFN-ℽ, TNF-α, IL-17, and IL-10, mainly in animals previously treated with EVs from DCs cultivated with yeast cells. It is worth highlighting that all prophylactic protocols modulated and minimized fungal growth compared to the control; that is, EVs contributed to the control of the infection and acted in favor of the host, demonstrating a protective character.

Polyphosphatases have a polyphosphate-independent influence on the virulence of Cryptococcus neoformans

Cryptococcus neoformans, an invasive basidiomycete fungal pathogen, causes one of the most prevalent, life-threatening diseases in immunocompromised individuals and accounts for ~19% of AIDS-associated deaths. Therefore, understanding the pathogenesis of C. neoformans and its interactions with the host immune system is critical for developing therapeutics against cryptococcosis. Previous studies demonstrated that C. neoformans cells lacking polyphosphate (polyP), an immunomodulatory polyanionic storage molecule, display altered cell surface architecture but unimpaired virulence in a murine model of cryptococcosis. However, the relevance of cell surface changes and the role of hyperaccumulation of polyP in the virulence of C. neoformans remain unclear. Here we show that mutants with abundant polyP due to loss of the polyphosphatases Xpp1 and Epp1 are attenuated for virulence. The double mutant differed from the wild type during disease by demonstrating a higher fungal burden in disseminated organs at the experimental endpoint and by provoking an altered immune response. An analysis of triple mutants lacking the polyphosphatases and the Vtc4 protein for polyP synthesis also caused attenuated virulence in mice, thus suggesting an influence of Xpp1 and/or Epp1 independent of polyP levels. A more detailed characterization revealed that Xpp1 and Epp1 play multiple roles by contributing to the organization of the cell surface, virulence factor production, the response to stress, and mitochondrial function. Overall, we conclude that polyphosphatases have additional functions in the pathobiology of C. neoformans beyond an influence on polyP levels.IMPORTANCECryptococcus neoformans causes one of the most prevalent fungal diseases in people with compromised immune systems and accounts for ~19% of AIDS-associated deaths worldwide. The continual increase in the incidence of fungal infections and limited treatment options necessitate the development of new antifungal drugs and improved diagnostics. Polyphosphate (polyP), an under-explored biopolymer, functions as a storage molecule, modulates the host immune response, and contributes to the ability of some fungal and bacterial pathogens to cause disease. However, the role of polyP in cryptococcal disease remains unclear. In this study, we report that the polyphosphatase enzymes that regulate polyP synthesis and turnover contribute to the virulence of C. neoformans in a mouse model of cryptococcosis. The polyphosphatases influenced the survival of C. neoformans in macrophages and altered the host immune response. In addition, the mutants lacking the enzymes have changes in cell surface architecture and size, as well as defects in both mitochondrial function and the stress response. By using mutants defective in the polyphosphatases and polyP synthesis, we demonstrate that many of the phenotypic contributions of the polyphosphatases are independent of polyP.

Transcriptomic atlas throughout Coccidioides development reveals key phase-enriched transcripts of this important fungal pathogen

Coccidioides spp. are highly understudied but significant dimorphic fungal pathogens that can infect both immunocompetent and immunocompromised people. In the environment, they grow as multicellular filaments (hyphae) that produce vegetative spores called arthroconidia. Upon inhalation by mammals, arthroconidia undergo a process called spherulation. They enlarge and undergo numerous nuclear divisions to form a spherical structure, and then internally segment until the spherule is filled with multiple cells called endospores. Mature spherules rupture and release endospores, each of which can form another spherule, in a process thought to facilitate dissemination. Spherulation is unique to Coccidioides, and its molecular determinants remain largely unknown. Here, we report the first high-density transcriptomic analyses of Coccidioides development, defining morphology-dependent transcripts and those whose expression is regulated by RYP1, a major regulator required for spherulation and virulence. Of approximately 9,000 predicted transcripts, we discovered 273 transcripts with consistent spherule-associated expression, 82 of which are RYP1-dependent, a set likely to be critical for Coccidioides virulence. ChIP-Seq revealed two distinct regulons of Ryp1: one shared between hyphae and spherules and the other unique to spherules. Spherulation regulation was elaborate, with the majority of 227 predicted transcription factors in Coccidioides displaying spherule-enriched expression. We identified provocative targets, including 20 transcripts whose expression is endospore-enriched and 14 putative secreted effectors whose expression is spherule-enriched, of which six are secreted proteases. To highlight the utility of these data, we selected a cluster of Ryp1-dependent, arthroconidia-associated transcripts and found that they play a role in arthroconidia cell wall biology, demonstrating the power of this resource in illuminating Coccidioides biology and virulence.

Application of Principal Component Analysis as a Prediction Model for Feline Sporotrichosis

Sporotrichosis is a worldwide zoonotic disease that is spreading and causing epidemics in large urban centers. Cats are the most susceptible species to develop the disease, which could cause significant systemic lesions. The aim was to investigate and to identify predictive indicators of disease progression by correlations between the blood profile (hematological and biochemical analytes) and cutaneous lesion patterns of 70 cats diagnosed with Sporothrix brasiliensis. The higher occurrence in male cats in this study could be related to being non-neutered and having access to open spaces. Principal component analysis (PCA) with two principal components, followed by binary logistic regression, and binary logistic regression analysis, with independent variables and backward elimination modeling, were performed to evaluate hematological (n = 56) and biochemical (n = 34) analytes, including red blood cells, hemoglobin, hematocrit, leukocytes, segmented neutrophils, band neutrophils, eosinophils, lymphocytes, monocytes, total plasma protein, albumin, urea, creatinine, and alanine aminotransferase. Two logistic regression models (PCA and independent variables) were employed to search for a predicted model to correlate fixed (isolated) and disseminated cutaneous lesion patterns. Total plasma protein concentration may be assessed during screening diagnosis as it has been recognized as an independent predictor for the dissemination of cutaneous lesion patterns, with the capability of serving as a predictive biomarker to identify the progression of cutaneous lesions induced by S. brasiliensis infections in cats.

Functional characterization of macrophages and change of Th1/Th2 balance in patients with pythiosis after Pythium insidiosum antigen immunotherapy

There has been limited research into the role of the Pythium insidiosum antigen (PIA) in modulating immune response in patients with pythiosis. This study investigated the balance of T helper type 2 (Th2) and T helper type 1 (Th1) responses after receiving PIA immunotherapy in patients with pythiosis. Next, the phagocytic activity and phagocytic index of IFN-γ primed PIA-treated macrophages were examined. Furthermore, the phagocytosis of infective P. insidiosum zoospores by macrophages was investigated. This work showed that the PIA vaccine induced Th1 response and M1 macrophages in patients with vascular pythiosis who survived and those with localized pythiosis. Phagocytic activity and phagocytic index were increased considerably in localized pythiosis patients compared to vascular pythiosis patients with hematological diseases. IFN-γ priming of PIA-treated macrophages against P. insidiosum zoospores enhanced the phagocytic activity and phagocytic index in vascular and localized pythiosis patients. Macrophages engulfed P. insidiosum zoospores, but the zoospores continued germination, resulting in macrophage death. Overall, our results suggest that PIA can modulate the immune responses, contributing to higher levels of Th1-type cytokine and potentially improving the survival of patients with vascular pythiosis. This study is the first to uncover that P. insidiosum zoospores can survive within macrophages.

Pleural Marginal Zone Lymphoma Masquerading as Metastatic Adenocarcinoma of the Lung

Extranodal marginal zone lymphoma (EMZL) is a rare subtype of non-Hodgkin's lymphoma characterized by the malignant transformation of lymphoid tissue at sites affected by chronic inflammation. Pleural marginal zone lymphoma (PMZL) is an infrequent manifestation of this condition. We report a case of PMZL co-occurring with primary lung adenocarcinoma. This case involves an 88-year-old female patient who presented to the emergency department with recurrent pleural effusions and symptoms suggestive of decompensated heart failure. A thoracentesis of the effusion revealed an aspergillus population. Throughout her hospitalization, the patient underwent multiple evaluations for malignancy; however, no conclusive findings emerged. Ultimately, PMZL and poorly differentiated primary adenocarcinoma of the lung were confirmed through random biopsies of the parietal pleura and lung opacities, respectively. The pleural pathology showed a monoclonal population of immunoglobulin G kappa, positive for cluster of differentiation (CD) markers CD20 and CD43. Consequently, she was treated with rituximab for PMZL, with plans to address the adenocarcinoma through stereotactic body radiation therapy (SBRT). Unfortunately, due to deconditioning from multiple hospitalizations and a pulmonary embolism, the patient chose comfort measures and subsequently passed away. Diagnosing PMZL can be challenging due to the absence of identifiable nodules. Reported cases have similarly required extensive investigations to reach a final diagnosis. While a direct correlation between chronic inflammation, frequent infectious pathogens, and the development of PMZL has yet to be established, a known association exists between EMZL and pathogens such as Helicobacter pylori in gastric involvement and Chlamydia psittaci in ocular adnexa. This report highlights the difficulties in obtaining a diagnosis for PMZL and examines the various mechanisms that may have contributed to this unusual finding.

Innate cells and STAT1-dependent signals orchestrate vaccine-induced protection against invasive Cryptococcus infection

Fungal pathogens are underappreciated causes of significant morbidity and mortality worldwide. In previous studies, we determined that a heat-killed, Cryptococcus neoformans fbp1-deficient strain (HK-fbp1) is a potent vaccine candidate. We determined that vaccination with HK-fbp1 confers protective immunity against lethal Cryptococcosis in an interferon γ (IFNγ)-dependent manner. In this study, we set out to uncover cellular sources and relevant targets of the protective effects of IFNγ in response to the HK-fbp1 vaccine. We found that early IFNγ production peaks at day 3 and that monocytes and neutrophils are important sources of this cytokine after vaccination. Neutralization of IFNγ at day 3 results in impaired CCR2+ monocyte recruitment and reduced differentiation into monocyte-derived dendritic cells (Mo-DC). In turn, depletion of CCR2+ cells prior to immunization results in impaired activation of IFNγ-producing CD4 and CD8 T cells. Thus, monocytes are important targets of innate IFNγ and help promote further IFNγ production by lymphocytes. We employed monocyte-fate mapper and conditional STAT1 knockout mice to uncover that STAT1 activation in CD11c+ cells, including alveolar macrophages, Mo-DCs, and monocyte-derived macrophages (Mo-Mac) is essential for HK-fbp1 vaccine-induced protection. Altogether, our aggregate findings suggest critical roles for innate cells as orchestrators of vaccine-induced protection against Cryptococcus infection.IMPORTANCEThe number of patients susceptible to invasive fungal infections across the world continues to rise at an alarming pace yet current antifungal drugs are often inadequate. Immune-based interventions and novel antifungal vaccines hold the promise of significantly improving patient outcomes. In previous studies, we identified a Cryptococcus neoformans mutant strain (Fbp1-deficient) as a potent, heat-inactivated vaccine candidate capable of inducing homologous and heterologous antifungal protection. In this study, we used a combination of methods together with a cohort of conditional knockout mouse strains to interrogate the roles of innate cells in the orchestration of vaccine-induced antifungal protection. We uncovered novel roles for neutrophils and monocytes as coordinators of a STAT1-dependent cascade of responses that mediate vaccine-induced protection against invasive cryptococcosis. This new knowledge will help guide the future development of much-needed antifungal vaccines.

Transcriptomic atlas of the morphologic development of the fungal pathogen Coccidioides reveals key phase-enriched transcripts

Coccidioides spp. are highly understudied but significant dimorphic fungal pathogens that can infect both immunocompetent and immunocompromised people. In the environment, they grow as multicellular filaments (hyphae) that produce vegetative spores called arthroconidia. Upon inhalation by mammals, arthroconidia undergo a process called spherulation. They enlarge and undergo numerous nuclear divisions to form a spherical structure, and then internally segment until the spherule is filled with multiple cells called endospores. Mature spherules rupture and release endospores, each of which can form another spherule, in a process thought to facilitate dissemination. Spherulation is unique to Coccidioides and its molecular determinants remain largely unknown. Here, we report the first high-density transcriptomic analyses of Coccidioides development, defining morphology-dependent transcripts and those whose expression is regulated by Ryp1, a major regulator required for spherulation and virulence. Of approximately 9000 predicted transcripts, we discovered 273 transcripts with consistent spherule-associated expression, 82 of which are RYP1-dependent, a set likely to be critical for Coccidioides virulence. ChIP-Seq revealed 2 distinct regulons of Ryp1, one shared between hyphae and spherules and the other unique to spherules. Spherulation regulation was elaborate, with the majority of 227 predicted transcription factors in Coccidioides displaying spherule-enriched expression. We identified provocative targets, including 20 transcripts whose expression is endospore-enriched and 14 putative secreted effectors whose expression is spherule-enriched, of which 6 are secreted proteases. To highlight the utility of these data, we selected a cluster of RYP1-dependent, arthroconidia-associated transcripts and found that they play a role in arthroconidia cell wall biology, demonstrating the power of this resource in illuminating Coccidioides biology and virulence.

The Road Ahead: Advancing Antifungal Vaccines and Addressing Fungal Infections in the Post-COVID World

In impoverished nations, the COVID-19 pandemic has led to a widespread occurrence of deadly fungal diseases like mucormycosis. The limited availability of effective antifungal treatments and the emergence of drug-resistant fungal strains further exacerbate the situation. Factors such as systemic steroid use, intravenous drug misuse, and overutilization of broad-spectrum antimicrobials contribute to the prevalence of hospital-acquired infections caused by drug-resistant fungi. Fungal infections exploit compromised immune status and employ intricate mechanisms to evade immune surveillance. The immune response involves the innate and adaptive immune systems, leading to phagocytic and complement-mediated elimination of fungi. However, resistance to antifungals poses a challenge, highlighting the importance of antifungal prophylaxis and therapeutic vaccination. Understanding the host-fungal immunological interactions and developing vaccines are vital in combating fungal infections. Further research is needed to address the high mortality and morbidity associated with multidrug-resistant fungal pathogens and to develop innovative treatment drugs and vaccines. This review focuses on the global epidemiological burden of fungal infections, host-fungal immunological interactions, recent advancements in vaccine development and the road ahead.

Novel Insights into Sporotrichosis and Diabetes

Sporotrichosis is a type of zoonotic subcutaneous mycosis caused by different species of dimorphic fungus of the genus Sporothrix, and it is the most common form of subcutaneous mycosis in Latin America. Sporotrichosis is generally restricted to cutaneous and lymphatic tissue (i.e., localized forms), and involvement in the viscera (i.e., disseminated or disseminated cutaneous form) is uncommon, especially in the central nervous system. However, immunosuppression in individuals with diabetes mellitus can lead to the disseminated form of the disease due to a failure to eliminate the pathogen and poor infection treatment outcomes. Possible correlations between patients with diabetes and their greater susceptibility to disseminated cases of sporotrichosis include a decreased cytokine response after stimulation, increased oxidative stress, decreased chemotaxis, phagocytic activity, adhesion and rolling of neutrophils and monocytes/macrophages, and increased macrophage/monocyte and polymorphonuclear cell apoptosis. Therefore, this review highlights novel insights into diabetes and sporotrichosis by investigating how chronic inflammation affects and aggravates the infection, the possible causes of the greater susceptibility of Sporothrix sp. to hematogenous dissemination in immunocompromised patients, and the main alterations that this dissemination can cause.

Exploring the immune characteristions of CRKP pneumonia at single-cell level

The immune dysregulation associated with carbapenem-resistant Klebsiella pneumoniae (CRKP) severity was investigated through single-cell RNA sequencing (scRNA-seq) of 5 peripheral blood samples from 3 patients with moderate and severe CRKP pneumonia. Additionally, scRNA-seq datasets from two individuals with COVID-19 were included for comparative analysis. The dynamic characterization and functional properties of each immune cell type were examined by delineating the transcriptional profiles of immune cells throughout the transition from moderate to severe conditions. Overall, most immune cells in CRKP patients exhibited a robust interferon-α response and inflammatory reaction compared to healthy controls, mirroring observations in COVID-19 patients. Furthermore, cell signatures associated with NK cells, macrophages, and monocytes were identified in CRKP progression including PTPRCAP for NK cells, C1QB for macrophages, and S100A12 for both macrophages and monocytes. In summary, this study offers a comprehensive scRNA-seq resource for illustrating the dynamic immune response patterns during CRKP progression, thereby shedding light on the associations between CRKP and COVID-19.

Helper T cell immunity in humans with inherited CD4 deficiency

CD4+ T cells are vital for host defense and immune regulation. However, the fundamental role of CD4 itself remains enigmatic. We report seven patients aged 5-61 years from five families of four ancestries with autosomal recessive CD4 deficiency and a range of infections, including recalcitrant warts and Whipple's disease. All patients are homozygous for rare deleterious CD4 variants impacting expression of the canonical CD4 isoform. A shorter expressed isoform that interacts with LCK, but not HLA class II, is affected by only one variant. All patients lack CD4+ T cells and have increased numbers of TCRαβ+CD4-CD8- T cells, which phenotypically and transcriptionally resemble conventional Th cells. Finally, patient CD4-CD8- αβ T cells exhibit intact responses to HLA class II-restricted antigens and promote B cell differentiation in vitro. Thus, compensatory development of Th cells enables patients with inherited CD4 deficiency to acquire effective cellular and humoral immunity against an unexpectedly large range of pathogens. Nevertheless, CD4 is indispensable for protective immunity against at least human papillomaviruses and Trophyrema whipplei.

New Immunological Markers in Chromoblastomycosis-The Importance of PD-1 and PD-L1 Molecules in Human Infection

The pathogenesis of chromoblastomycosis (CBM) is associated with Th2 and/or T regulatory immune responses, while resistance is associated with a Th1 response. However, even in the presence of IFN-γ, fungi persist in the lesions, and the reason for this persistence is unknown. To clarify the factors associated with pathogenesis, this study aimed to determine the polarization of the cellular immune response and the densities of cells that express markers of exhaustion in the skin of CBM patients. In the skin of patients with CBM, a moderate inflammatory infiltrate was observed, characterized primarily by the occurrence of histiocytes. Analysis of fungal density allowed us to divide patients into groups that exhibited low and high fungal densities; however, the intensity of the inflammatory response was not related to mycotic loads. Furthermore, patients with CBM exhibited a significant increase in the number of CD4+ and CD8+ cells associated with a high density of IL-10-, IL-17-, and IFN-γ-producing cells, indicating the presence of a chronic and mixed cellular immune response, which was also independent of fungal load. A significant increase in the number of PD-1+ and PD-L1+ cells was observed, which may be associated with the maintenance of the fungus in the skin and the progression of the disease.

Role of sphingolipids in the host-pathogen interaction

Fungal pathogens have been under the spotlight as their expanding geographic range combined with their potential harm to vulnerable populations turns them into increasingly threats to public health. Therefore, it is ultimately important to unveil the mechanisms associated with their infection process for further new treatment discovery. With this purpose, sphingolipid-based research has gained attention over the last years as these molecules have key properties that can regulate fungal pathogenicity. Here we discuss some of these properties as well as their role in fungal diseases, focusing on the subgroup of glycosphingolipids, as they represent promising molecules for drug discovery and for the development of fungal vaccines.

Implications of CD45RA and CD45RO T cell subsets in patients of chronic rhinosinusitis with nasal polyposis infected with Aspergillus flavus

T cell subsets (CD4 and CD8) play a prominent role in the development of chronic rhinosinusitis with nasal polyposis (CRSwNP). Colonization with Aspergillus flavus is recognized as a trigger for the growth of nasal polyps. The fungal proteins initiate the recruitment of T cells into the nasal mucosa, which contributes to the progression of nasal polyps. The study included 50 cases of CRSwNP and 50 healthy controls. Biopsies were subjected to KOH and culture for mycological investigation. We examined the changes in T helper (CD4+) and T cytotoxic (CD8+) in total T cells (CD3+) and expression of naive (CD45RA) and memory (CD45RO) cell markers in T cell subsets in peripheral blood mononuclear cells (PBMCs) challenged by A. flavus antigens in cases before and after treatment and in healthy controls by flow cytometry. Predominantly, A. flavus (86%) identified in nasal polyp biopsies of patients. An increased percentage of CD3+CD4+ T cells observed after A. flavus stimulation in patients when compared with healthy controls. The expression of CD4+CD45RA+ cells was significantly (P < .05) reduced in patients and increased CD4+CD45RO+ was observed upon stimulation with A. flavus in patients when compared with healthy control. Continuous exposure to inhaled fungal spores may induce aberrant immune responses to A. flavus spores, causing an allergic immunological reaction with high CD4+T cell responses, resulting in an unfavourable outcome. Elevated CD4+CD45RO+ T cells may transform the pathogenic response and highlight the chances of A. flavus reactive T cells involvement in prompting inflammation in CRSwNP.

Detailed characterisation of invasive aspergillosis in a murine model of X-linked chronic granulomatous disease shows new insights in infections caused by Aspergillus fumigatus versus Aspergillus nidulans

Introduction

Invasive aspergillosis (IA) is the most prevalent infectious complication in patients with chronic granulomatous disease (CGD). Yet, understanding of fungal pathogenesis in the CGD host remains limited, particularly with regards to A. nidulans infection.

Methods

We have used a murine model of X-linked CGD to investigate how the pathogenesis of IA varies between A. fumigatus and A. nidulans, comparing infection in both X-linked CGD (gp91-/-) mice and their parent C57BL/6 (WT) mice. A 14-colour flow cytometry panel was used to assess the cell dynamics over the course of infection, with parallel assessment of pulmonary cytokine production and lung histology.

Results

We observed a lack of association between pulmonary pathology and infection outcome in gp91-/- mice, with no significant mortality in A. nidulans infected mice. An overwhelming and persistent neutrophil recruitment and IL-1 release in gp91-/- mice following both A. fumigatus and A. nidulans infection was observed, with divergent macrophage, dendritic cell and eosinophil responses and distinct cytokine profiles between the two infections.

Conclusion

We have provided an in-depth characterisation of the immune response to pulmonary aspergillosis in an X-linked CGD murine model. This provides the first description of distinct pulmonary inflammatory environments in A. fumigatus and A. nidulans infection in X-linked CGD and identifies several new avenues for further research.

Review on host-pathogen interaction in dermatophyte infections

Dermatophytosis is a common superficial fungal infection of the skin and its appendages caused by dermatophytes. Recent times have witnessed a dynamic evolution of dermatophytes driven by their ecology, reproduction, pathogenicity and host immune response, influenced by population migration and socioeconomic status. Dermatophytes establish infection following successful adherence of arthroconidia to the surface of keratinized tissues. The proteolytic enzymes released during adherence and invasion not only ascertain their survival but also allow the persistence of infection in the host. While the cutaneous immune surveillance mechanism, after antigen exposure and presentation, leads to activation of T lymphocytes and subsequent clonal expansion generating effector T cells that differentially polarize to a predominant Th17 response, the response fails to eliminate the pathogen despite the presence of high levels of IFN-γ. In chronic dermatophytosis, antigens are a constant source of stimulus promoting a dysregulated Th17 response causing inflammation. The host-derived iTreg response fails to counterbalance the inflammation and instead polarizes to Th17 lineage, aggravating the chronicity of the infection. Increasing antifungal resistance and recalcitrant dermatophytosis has impeded the overall clinical remission. Human genetic research has the potential to generate knowledge to explore new therapeutic targets. The review focuses on understanding specific virulence factors involved in pathogenesis and defining the role of dysregulated host immune response against chronic dermatophytic infections for future management strategies.

Effects of combination of Cryptococcus gattii and IFN-γ, IL-4 or IL-27 on human bronchial epithelial cells

BACKGROUND

Airway epithelial cells are crucial for the establishment of cryptococcosis. In experimental cryptococcosis, the Th2 immune response is associated with host susceptibility, while Th1 cells are associated with protection. The absence of IL-27 receptor alpha in mice favor the increase Cryptococcus neoformans burden in the lung. Here, we evaluated the effects of the combination of IL-4, IFN-γ or IL-27 with C. gattii on human bronchial epithelial cells (BEAS-2B).

METHODS

BEAS-2B were stimulated with IL-4, IFN-γ or IL-27 (100 ng/mL) and/or live yeast forms of C. gattii (multiplicities of infection (MOI) of 1-100) and vice-versa, as well as with heat-killed cells of C. gattii for 24 h.

RESULTS

None of the C. gattii MOIs had cytotoxic effects on BEAS-2B when compared to control. The cells stimulated by cytokines (IL-4, IFN-γ or IL-27) followed by live yeast forms of C. gattii (MOI of 100) infection and vice-versa demonstrated a reduction in IL-6, IL-8 and/or CCL2 production and activation of STAT6 (induced by IL-4) and STAT1 (induced by IL-27 or IFN-γ) when compared to cells stimulated with C. gattii, IL-4, IFN-γ or IL-27. In the combination of cytokines and heat-killed cells of C. gattii, no inhibition of these inflammatory parameters was observed. The growth of C. gattii was increased while the phagocytosis of live yeast forms of C. gattii in the BEAS-2B were reduced in the presence of IL-4, IFN-γ or IL-27. Conclusion The association of live yeast forms, but not heat-killed yeast forms, of C. gattii with IL-4, IFN-γ or IL-27 induced an anti-inflammatory effect.

T cell responses to control fungal infection in an immunological memory lens

In recent years, fungal vaccine research emanated significant findings in the field of antifungal T-cell immunity. The generation of effector T cells is essential to combat many mucosal and systemic fungal infections. The development of antifungal memory T cells is integral for controlling or preventing fungal infections, and understanding the factors, regulators, and modifiers that dictate the generation of such T cells is necessary. Despite the deficiency in the clear understanding of antifungal memory T-cell longevity and attributes, in this review, we will compile some of the existing literature on antifungal T-cell immunity in the context of memory T-cell development against fungal infections.

Harnessing the Immune Response to Fungal Pathogens for Vaccine Development

Invasive fungal infections are emerging diseases that kill over 1.5 million people per year worldwide. With the increase of immunocompromised populations, the incidence of invasive fungal infections is expected to continue to rise. Vaccines for viral and bacterial infectious diseases have had a transformative impact on human health worldwide. However, no fungal vaccines are currently in clinical use. Recently, interest in fungal vaccines has grown significantly. One Candida vaccine has completed phase 2 clinical trials, and research on vaccines against coccidioidomycosis continues to advance. Additionally, multiple groups have discovered various Cryptococcus mutant strains that promote protective responses to subsequent challenge in mouse models. There has also been progress in antibody-mediated fungal vaccines. In this review, we highlight recent fungal vaccine research progress, outline the wealth of data generated, and summarize current research for both fungal biology and immunology studies relevant to fungal vaccine development. We also review technological advancements in vaccine development and highlight the future prospects of a human vaccine against invasive fungal infections.

Immunological effects of anti-IL-17/12/23 therapy in patients with psoriasis complicated by Candida infections

Biologics that block the T-helper-17 pathway are very effective in the treatment of psoriasis and other inflammatory diseases. However, interleukin-17 is also crucial for antifungal host defense, and clinical trial data suggest an increase in the incidence of Candida infections during IL-17 inhibitor (IL-17i) therapy. We investigated the innate and adaptive immune responses of psoriasis patients with a history of skin and/or mucosal candidiasis during IL-17i or IL-12/23i therapy, comparing those responses to healthy controls. Psoriasis patients with IL-17i showed significantly lower CD4+Th1-like (CCR6^-CXCR3⁺CCR4^-) and Th1Th17-like (CD4⁺CCR6⁺CXCR3⁺CCR4^-) cell percentages. Patient cells stimulated with Candida albicans produced significantly lower IL-6 in the IL-12/23i group and IL-1β production in the IL-17i group, while the release of TNF-α and ROS was similar between patients and controls. IFN-γ and IL-10 production in response to several stimuli after 7 days was particularly decreased in patients receiving IL-17i therapy. Finally, after stimulation with the polarizing cytokines IL-1β and IL-23, the Th17 cytokine response was significantly lower in the IL-17i patient group. These innate and adaptive immune response defects can diminish antifungal host immune response and thereby increase susceptibility to candidiasis in patients treated with IL-17i or IL-12/23i.

Root Causes of Fungal Coinfections in COVID-19 Infected Patients

COVID-19 is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and has infected over 200 million people, causing over 4 million deaths. COVID-19 infection has been shown to lead to hypoxia, immunosuppression, host iron depletion, hyperglycemia secondary to diabetes mellitus, as well as prolonged hospitalizations. These clinical manifestations provide favorable conditions for opportunistic fungal pathogens to infect hosts with COVID-19. Interventions such as treatment with corticosteroids and mechanical ventilation may further predispose COVID-19 patients to acquiring fungal coinfections. Our literature review found that fungal coinfections in COVID-19 infected patients were most commonly caused by Aspergillus, Candida species, Cryptococcus neoformans, and fungi of the Mucorales order. The distribution of these infections, particularly Mucormycosis, was found to be markedly skewed towards low- and middle-income countries. The purpose of this review is to identify possible explanations for the increase in fungal coinfections seen in COVID-19 infected patients so that physicians and healthcare providers can be conscious of factors that may predispose these patients to fungal coinfections in order to provide more favorable patient outcomes. After identifying risk factors for coinfections, measures should be taken to minimize the dosage and duration of drugs such as corticosteroids, immunosuppressants, and antibiotics.

The important role of fungi in inflammatory bowel diseases

Inflammatory bowel disease (IBD) is a life-threatening and chronic inflammatory disease of gastrointestinal tissue, with complex pathogenesis. Current research on IBD has mainly focused on bacteria; however, the role of fungi in IBD is largely unknown due to the incomplete annotation of fungi in current genomic databases. With the development of molecular techniques, the gut mycobiome has been found to have great diversity. In addition, increasing evidence has shown intestinal mycobiome plays an important role in the physiological and pathological processes of IBD. In this review, we will systemically introduce the recent knowledge about multi-dimensional fungal dysbiosis associated with IBD, the interactions between fungus and bacteria, the role of fungi in inflammation in IBD, and highlight recent advances in the potential therapeutic role of fungus in IBD, which may hold the keys to develop new predictive, therapeutic or prognostic approaches in IBD.

IFN-γ Mediated Signaling Improves Fungal Clearance in Experimental Pulmonary Mucormycosis

We established three immunocompetent murine models of pulmonary mucormycosis to determine the involvement of the adaptive immune response in host resistance in pulmonary mucormycosis, a rapidly fatal disease caused mainly by Rhizopus spp. Immunocompetent inbred (C57BL/6, BALB/c) and outbred (Swiss) strains of mice were inoculated with R. oryzae via the intratracheal route. The inoculation resulted in a disseminated infection that spread to the brain, spleen, kidney, and liver. After 7 and 30 days of R. oryzae infection, BALB/c mice showed the lowest fungal load and highest production of IFN-γ and IL-2 by splenocytes. Swiss mice showed a higher fungal load 30 days p.i. and was associated with a weak development of the Th-1 profile. To confirm our findings, R. oryzae-infected IFN-γ⁻/⁻ mice were evaluated after 60 days, where the mice still showed viable fungi in the lungs. This study showed, for the first time, that pulmonary mucormycosis in three widely used mouse strains resulted in an acute fungal dissemination without immunosuppression whose outcome varies according to the genetic background of the mice. We also identified the partial role of IFN-γ in the efficient elimination of R. oryzae during pulmonary infection.

The Role of B-Cells and Antibodies against Candida Vaccine Antigens in Invasive Candidiasis

Systemic candidiasis is an invasive fungal infection caused by members of the genus Candida. The recent emergence of antifungal drug resistance and increased incidences of infections caused by non-albicans Candida species merit the need for developing immune therapies against Candida infections. Although the role of cellular immune responses in anti-Candida immunity is well established, less is known about the role of humoral immunity against systemic candidiasis. This review summarizes currently available information on humoral immune responses induced by several promising Candida vaccine candidates, which have been identified in the past few decades. The protective antibody and B-cell responses generated by polysaccharide antigens such as mannan, β-glucan, and laminarin, as well as protein antigens like agglutinin-like sequence gene (Als3), secreted aspartyl proteinase (Sap2), heat shock protein (Hsp90), hyphally-regulated protein (Hyr1), hyphal wall protein (Hwp1), enolase (Eno), phospholipase (PLB), pyruvate kinase (Pk), fructose bisphosphate aldolase (Fba1), superoxide dismutase gene (Sod5) and malate dehydrogenase (Mdh1), are outlined. As per studies reviewed, antibodies induced in response to leading Candida vaccine candidates contribute to protection against systemic candidiasis by utilizing a variety of mechanisms such as opsonization, complement fixation, neutralization, biofilm inhibition, direct candidacidal activity, etc. The contributions of B-cells in controlling fungal infections are also discussed. Promising results using anti-Candida monoclonal antibodies for passive antibody therapy reinforces the need for developing antibody-based therapeutics including anti-idiotypic antibodies, single-chain variable fragments, peptide mimotopes, and antibody-derived peptides. Future research involving combinatorial immunotherapies using humanized monoclonal antibodies along with antifungal drugs/cytokines may prove beneficial for treating invasive fungal infections.

In vitro infection models to study fungal-host interactions

Fungal infections (mycoses) affect over a billion people per year. Approximately, two million of these infections are life-threatening, especially for patients with a compromised immune system. Fungi of the genera Aspergillus, Candida, Histoplasma and Cryptococcus are opportunistic pathogens that contribute to a substantial number of mycoses. To optimize the diagnosis and treatment of mycoses, we need to understand the complex fungal-host interplay during pathogenesis, the fungal attributes causing virulence and how the host resists infection via immunological defenses. In vitro models can be used to mimic fungal infections of various tissues and organs and the corresponding immune responses at near-physiological conditions. Furthermore, models can include fungal interactions with the host-microbiota to mimic the in vivo situation on skin and mucosal surfaces. This article reviews currently used in vitro models of fungal infections ranging from cell monolayers to microfluidic 3D organ-on-chip (OOC) platforms. We also discuss how OOC models can expand the toolbox for investigating interactions of fungi and their human hosts in the future.

TRIM31 facilitates K27-linked polyubiquitination of SYK to regulate antifungal immunity

Spleen tyrosine kinase (SYK) is a non-receptor tyrosine kinase, which plays an essential role in both innate and adaptive immunity. However, the key molecular mechanisms that regulate SYK activity are poorly understood. Here we identified the E3 ligase TRIM31 as a crucial regulator of SYK activation. We found that TRIM31 interacted with SYK and catalyzed K27-linked polyubiquitination at Lys375 and Lys517 of SYK. This K27-linked polyubiquitination of SYK promoted its plasma membrane translocation and binding with the C-type lectin receptors (CLRs), and also prevented the interaction with the phosphatase SHP-1. Therefore, deficiency of Trim31 in bone marrow-derived dendritic cells (BMDCs) and macrophages (BMDMs) dampened SYK-mediated signaling and inhibited the secretion of proinflammatory cytokines and chemokines against the fungal pathogen Candida albicans infection. Trim31^-/- mice were also more sensitive to C. albicans systemic infection than Trim31^+/+ mice and exhibited reduced Th1 and Th17 responses. Overall, our study uncovered the pivotal role of TRIM31-mediated K27-linked polyubiquitination on SYK activation and highlighted the significance of TRIM31 in anti-C. albicans immunity.

Challenges and Opportunities in Understanding Genetics of Fungal Diseases: Towards a Functional Genomics Approach

Infectious diseases are a leading cause of morbidity and mortality worldwide, and human pathogens have long been recognized as one of the main sources of evolutionary pressure, resulting in a high variable genetic background in immune-related genes. The study of the genetic contribution to infectious diseases has undergone tremendous advances over the last decades. Here, focusing on genetic predisposition to fungal diseases, we provide an overview of the available approaches for studying human genetic susceptibility to infections, reviewing current methodological and practical limitations. We describe how the classical methods available, such as family-based studies and candidate gene studies, have contributed to the discovery of crucial susceptibility factors for fungal infections. We will also discuss the contribution of novel unbiased approaches to the field, highlighting their success but also their limitations for the fungal immunology field. Finally, we show how a systems genomics approach can overcome those limitations and can lead to efficient prioritization and identification of genes and pathways with a critical role in susceptibility to fungal diseases. This knowledge will help to stratify at-risk patient groups and, subsequently, develop early appropriate prophylactic and treatment strategies.

Unconventional T cells - New players in antifungal immunity

Life-threatening invasive fungal diseases (IFD) are increasing in incidence, especially in immunocompromised patients and successful resolution of IFD requires a variety of different immune cells. With the limited repertoire of available antifungal drugs there is a need for more effective therapeutic strategies. This review interrogates the evidence on the human immune response to the main pathogens driving IFD, with a focus on the role of unconventional lymphocytes e.g. natural killer (NK) cells, gamma/delta (γδ) T cells, mucosal associated invariant T (MAIT) cells, invariant natural killer T (iNKT) cells and innate lymphoid cells (ILC). Recent discoveries and new insights into the roles of these novel lymphocyte groups in antifungal immunity will be discussed, and we will explore how an improved understanding of antifungal action by lymphocytes can inform efforts to improve antifungal treatment options.

Initiation and Pathogenesis of Severe Asthma with Fungal Sensitization

Fungi represent one of the most diverse and abundant eukaryotes on earth, and their ubiquity and small proteolytically active products make them pervasive allergens that affect humans and other mammals. The immunologic parameters surrounding fungal allergies are still not fully elucidated despite their importance given that a large proportion of severe asthmatics are sensitized to fungal allergens. Herein, we explore fungal allergic asthma with emphasis on mouse models that recapitulate the characteristics of human disease, and the main leukocyte players in the pathogenesis of fungal allergies. The endogenous mycobiome may also contribute to fungal asthma, a phenomenon that we discuss only superficially, as much remains to be discovered.

Sporothrix Brasiliensis: A Review of an Emerging South American Fungal Pathogen, Its Related Disease, Presentation and Spread in Argentina

Sporotrichosis, caused by Sporothrix schenckii and related species, is the most frequent implantation mycosis in Latin America. In Argentina, over the last 8 years, there have been 0.16 new cases per month of feline sporotrichosis in 2011, increasing to 0.75 cases per month in 2019 and involving zoonotic transmission to humans. Molecular identification by polymerase chain reaction (PCR) detected Sporothrix brasiliensis in these feline and zoonotic outbreaks. This study will focus on different feline and human sporotrichosis outbreaks caused by S. brasiliensis in Argentina during 2011–2019. We will address the sources of infection and environmental hotspots, as well as the application of several treatment strategies for improving the pharmacotherapy of the different clinical forms of the disease. Finally, we will provide a detailed summary of the clinical aspects and new advances in host–pathogen interactions, virulence factors and immune response, focusing on state-of-the-art diagnostic tools and potential vaccine candidates.

Fungal natural products galaxy: Biochemistry and molecular genetics toward blockbuster drugs discovery

Secondary metabolites synthesized by fungi have become a precious source of inspiration for the design of novel drugs. Indeed, fungi are prolific producers of fascinating, diverse, structurally complex, and low-molecular-mass natural products with high therapeutic leads, such as novel antimicrobial compounds, anticancer compounds, immunosuppressive agents, among others. Given that these microorganisms possess the extraordinary capacity to secrete diverse chemical scaffolds, they have been highly exploited by the giant pharma companies to generate small molecules. This has been made possible because the isolation of metabolites from fungal natural sources is feasible and surpasses the organic synthesis of compounds, which otherwise remains a significant bottleneck in the drug discovery process. Here in this comprehensive review, we have discussed recent studies on different fungi (pathogenic, non-pathogenic, commensal, and endophytic/symbiotic) from different habitats (terrestrial and marines), the specialized metabolites they biosynthesize, and the drugs derived from these specialized metabolites. Moreover, we have unveiled the logic behind the biosynthesis of vital chemical scaffolds, such as NRPS, PKS, PKS-NRPS hybrid, RiPPS, terpenoids, indole alkaloids, and their genetic mechanisms. Besides, we have provided a glimpse of the concept behind mycotoxins, virulence factor, and host immune response based on fungal infections.

The gut mycobiome: a novel player in chronic liver diseases

The human gut microbiome (bacteria, fungi, viruses, and archaea) is a complex and diverse ecosystem. It plays an important role in human health, but is involved in several intestinal and extraintestinal diseases. Most research to date has focused on the role of bacteria, while studies focusing on fungi (also referred to as "mycobiome" or "fungome") are still in its infancy. In this review, we focus on the existing literature available about the gut mycobiome with an emphasis on compositional mycobiome changes associated with liver diseases, the impact on pathogenesis of disease, and its potential use as therapeutic targets. We also provide insights into current methodologies of studying mycobiome, and we highlight the interkingdom interactions in the context of disease and how they affect health of the host. Herein, by focusing on the gut mycobiome, this review provides novel insights and directions for liver research.

The sino-nasal warzone: transcriptomic and genomic studies on sino-nasal aspergillosis in dogs

We previously showed that each dog with chronic non-invasive sino-nasal aspergillosis (SNA) was infected with a single genotype of Aspergillus fumigatus. Here, we studied the transcriptome of this fungal pathogen and the canine host within the biofilm resulting from the infection. We describe here transcriptomes resulting from natural infections in animal species with A. fumigatus. The host transcriptome showed high expression of IL-8 and alarmins, uncontrolled inflammatory reaction and dysregulation of the Th17 response. The fungal transcriptome showed in particular expression of genes involved in secondary metabolites and nutrient acquisition. Single-nucleotide polymorphism analysis of fungal isolates from the biofilms showed large genetic variability and changes related with adaptation to host environmental factors. This was accompanied with large phenotypic variability in in vitro stress assays, even between isolates from the same canine patient. Our analysis provides insights in genetic and phenotypic variability of Aspergillus fumigatus in biofilms of naturally infected dogs reflecting in-host adaptation. Absence of a Th17 response and dampening of the Th1 response contributes to the formation of a chronic sino-nasal warzone.

Molecularly Distinct NLRP3 Inducers Mediate Diverse Ratios of Interleukin-1β and Interleukin-18 from Human Monocytes

Inflammasomes cleave and activate interleukin- (IL-) 1β and IL-18 which have both shared and unique biological functions. IL-1β is an important mediator of the acute phase response to infections and tissue damage, whereas IL-18 takes part in activation and tailoring of the adaptive immune response. While IL-1β has served as the prototypic indicator of inflammasome activation, few studies have compared the potential differences in IL-1β and IL-18 production during inflammasome activation. Since these cytokines partake in different immune pathways, the involvement of inflammasome activity in different conditions needs to be described beyond IL-1β production alone. To address a potential heterogeneity in inflammasome functionality, ATP, chitosan, or silica oxide (SiO₂) were used to induce NLRP3 inflammasome activation in THP-1 cells and the subsequent outcomes were quantified. Despite using doses of the inflammasome inducers yielding similar release of IL-1β, SiO₂-stimulated cells showed a lower concentration of released IL-18 compared to ATP and chitosan. Hence, the cells stimulated with SiO₂ responded with a distinctly different IL-18 : IL-1β ratio. The difference in the IL-18 : IL-1β ratio for SiO₂ was constant over different doses. While all downstream responses were strictly dependent on a functional NLRP3 inflammasome, the differences did not depend on the level of gene expression, caspase-1 activity, or pyroptosis. We suggest that the NLRP3 inflammasome response should be considered a dynamic process, which can be described by taking the ratio between IL-1β and IL-18 into account and moving away from an on/off perspective of inflammasome activation.

Correlation between clinical outcome and tissue inflammatory response in kidney transplant recipients with cryptococcosis

Cryptococcosis is the second most common invasive fungal infection reported in renal transplant recipients. Tissue granulomatous inflammation is necessary to contain Cryptococcus infection. This study aims to analyze the granuloma patterns and in situ expression of regulatory T (Treg) immune response in tissue samples from 12 renal transplant recipients with cryptococcosis. Fungal isolates were molecularly identified as Cryptococcus neoformans species complex. A detailed characterization of granulomas in tissue samples from 12 kidney transplant recipients with cryptococcosis was described by checking six lung and six skin biopsies by conventional histology and for immunohistochemical detection of CD4 and Treg markers: forkhead box P3 (FoxP3), interleukin (IL)-10 and transforming-growth factor (TGF)-β. Granulomas were classified as compact, loose or mixed. Patients with mixed (n = 4) and compact (n = 3) granulomatous inflammation patterns were associated with a better prognosis and presented a higher number of CD4+FoxP3+T cells compared to the group of patients with loose granulomas. In counterpart, three out of five patients with loose granulomas died with cryptococcosis. We suggest that Treg may have a protective role in the tissue response to Cryptococcus infection given its association with compact and mixed granulomas in patients with better clinical outcomes.

Tregs in the immune response of BALB/c mice experimentally infected with species of the Sporothrix genus

Background: Sporotrichosis occurs through contact with contaminated soil and plant. However, the incidence of sporotrichosis as a zoonotic epidemic has increased, particularly in Rio de Janeiro. Aim: In this work, we decided to evaluate some T-cell phenotypes involved in the immune response. Materials & methods: We used flow cytometry to quantify TCD4⁺ and TCD8⁺ and Treg from immunocompetent and immunosuppressed mice infected with Sporothrix species with different levels of virulence and pathogenicity. Results: It was demonstrated the predominance of TCD4⁺ over the TCD8⁺ cells in both groups, inoculated with all the species, and percentages of Treg observed in infected immunocompetent mice. Conclusion: This regulatory phenotype can be associated with a protective immunity in the initial periods of infection.

Importance of Candida Antigenic Factors: Structure-Driven Immunomodulation Properties of Synthetically Prepared Mannooligosaccharides in RAW264.7 Macrophages

The incidence and prevalence of serious fungal infections is rising, especially in immunosuppressed individuals. Moreover, co-administration of antibiotics and immunosuppressants has driven the emergence of new multidrug-resistant pathogens. The significant increase of multidrug-resistant pathogens, together with their ability to form biofilms, is associated with morbidity and mortality. Research on novel synthetically prepared immunomodulators as potential antifungal immunotherapeutics is of serious interest. Our study demonstrated the immunobiological activity of synthetically prepared biotinylated mannooligosaccharides mimicking Candida antigenic factors using RAW264.7 macrophages. Macrophage exposure to the set of eight structurally different mannooligosaccharides induced a release of Th1, Th2, Th17, and Treg cytokine signature patterns. The observed immune responses were tightly associated with structure, dose, exposure time, and selected signature cytokines. The viability/cytotoxicity of the mannooligosaccharide formulas was assessed based on cell proliferation. The structure-based immunomodulatory activity of the formulas was evaluated with respect to the length, branching and conformation of the various formulas. Glycoconjugate formulas with terminal β-mannosyl-units tended to be more potent in terms of Candida relevant cytokines IL-12 p70, IL-17, GM-CSF, IL-6, and TNFα induction and cell proliferation, and this tendency was associated with structural differences between the studied glycoconjugate formulas. The eight tested mannooligosaccharide conjugates can be considered potential in vitro immunomodulative agents suitable for in vitro Candida diagnostics or prospectively for subcellular anti-Candida vaccine design.

Disseminated blastomycosis in coalworkers' pneumoconiosis

Blastomyces dermatitidis is a thermally dimorphic fungus that can cause pulmonary, extrapulmonary, or disseminated infections. Though it can infect both immune-competent and immunocompromised hosts, the disease can be severe in immunocompromised hosts. Exposure to silica dust is associated with silicosis, and this is associated with impaired immunity and an increased risk of mycobacterial and fungal infections. The fungal infections commonly associated with pneumoconiosis are pulmonary aspergillosis, histoplasmosis, coccidioidomycosis, and cryptococcosis. However, there is a dearth of data on the association of pneumoconiosis and blastomycosis. Clinical deterioration and new cavitary lesions in patients with pneumoconiosis should alert clinicians of new pulmonary infection. Traditional sputum sampling may lead to poor diagnostic yield, because the organism is frequently surrounded by a fibrotic wall. Aggressive diagnostic testing with lung or skin biopsies may be warranted. We present the first reported case of disseminated blastomycosis in a patient with coalworkers' pneumoconiosis.

Sporothrix brasiliensis induces a more severe disease associated with sustained Th17 and regulatory T cells responses than Sporothrix schenckii sensu stricto in mice

Little is known about the differences in the CD4+ T-cell response induced by Sporothrix schenckii and Sporothrix brasiliensis, the most virulent species that cause sporotrichosis. Here, the helper (Th) and regulatory T cells (Tregs) responses were evaluated comparatively in a murine model of sporotrichosis on days 7, 21 and 35 after subcutaneous infection with either S. schenckii or S. brasiliensis conidia. The fungal load was measured at the site of infection, as well as in the liver and spleen. The Th1/Th17/Tregs responses were analyzed in the spleen, while the level of IL-2, IL-4, IL-6, TNF-alpha, IFN-ɣ, IL-17A and IL-10 cytokines were measured at the local site of infection on 24 h postinfections and in sera on the indicated days. S. brasiliensis caused a longer-lasting infection in the skin and chronic systemic dissemination associated to more severe granulomatous lesions. Similar Th1/Th1-Th17/Tregs responses were induced by both S. brasiliensis and S. schenckii on 7th and 21st d.p.i but on 35 d.p.i a reduction of Th1 and Th1-Th17 cells, associated to higher values of Th17/Tregs cells was observed only in S. brasiliensis-infected mice. In summary, S. brasiliensis caused a more severe disease associated with sustained Th17/Tregs responses than S. schenckii in mice.

Methods of Controlling Invasive Fungal Infections Using CD8+ T Cells

Invasive fungal infections (IFIs) cause high rates of morbidity and mortality in immunocompromised patients. Pattern-recognition receptors present on the surfaces of innate immune cells recognize fungal pathogens and activate the first line of defense against fungal infection. The second line of defense is the adaptive immune system which involves mainly CD4+ T cells, while CD8+ T cells also play a role. CD8+ T cell-based vaccines designed to prevent IFIs are currently being investigated in clinical trials, their use could play an especially important role in acquired immune deficiency syndrome patients. So far, none of the vaccines used to treat IFI have been approved by the FDA. Here, we review current and future antifungal immunotherapy strategies involving CD8+ T cells. We highlight recent advances in the use of T cells engineered using a Sleeping Beauty vector to treat IFIs. Recent clinical trials using chimeric antigen receptor (CAR) T-cell therapy to treat patients with leukemia have shown very promising results. We hypothesized that CAR T cells could also be used to control IFI. Therefore, we designed a CAR that targets β-glucan, a sugar molecule found in most of the fungal cell walls, using the extracellular domain of Dectin-1, which binds to β-glucan. Mice treated with D-CAR+ T cells displayed reductions in hyphal growth of Aspergillus compared to the untreated group. Patients suffering from IFIs due to primary immunodeficiency, secondary immunodeficiency (e.g., HIV), or hematopoietic transplant patients may benefit from bioengineered CAR T cell therapy.