Adjuvant ArtinM favored the host immunity against Cryptococcus gattii infection in C57BL/6 mice

Aim: Cryptococcus gattii causes a severe fungal infection with high mortality rate among immunosuppressed and immunocompetent individuals. Due to limitation of current antifungal treatment, new immunotherapeutic approaches are explored. Methods: This study investigated an immunization strategy utilizing heat-inactivated C. gattii with ArtinM as an adjuvant. C57BL/6 mice were intranasally immunized with heat-killed C. gattii and ArtinM was administrated either before immunization or along with HK-C. gattii. Mice were infected with C. gattii and the efficacy of the immunization protocol was evaluated. Results: Mice that received ArtinM exhibited increased levels of IL-10 and relative expression of IL-23 in the lungs, reduced fungal burden and preserved tissue integrity post-infection. Conclusion: Adjuvant ArtinM improved immunization against C. gattii infection in C57BL/6 mice.

Microorganisms populating the water-related indoor biome

Modernisation of our households created novel opportunities for microbial growth and thus changed the array of microorganisms we come in contact with. While many studies have investigated microorganisms in the air and dust, tap water, another major input of microbial propagules, has received far less attention. The quality of drinking water in developed world is strictly regulated to prevent immediate danger to human health. However, fungi, algae, protists and bacteria of less immediate concern are usually not screened for. These organisms can thus use water as a vector of transmission into the households, especially if they are resistant to various water treatment procedures. Good tolerance of unfavourable abiotic conditions is also important for survival once microbes enter the household. Limitation of water availability, high or low temperatures, application of antimicrobial chemicals and other measures are taken to prevent indoor microbial overgrowth. These conditions, together with a large number of novel chemicals in our homes, shape the diversity and abundance of indoor microbiota through constant selection of the most resilient species, resulting in a substantial overlap in diversity of indoor and natural extreme environments. At least in fungi, extremotolerance has been linked to human pathogenicity, explaining why many species found in novel indoor habitats (such as dishwasher) are notable opportunistic pathogens. As a result, microorganisms that often enter our households with water and are then enriched in novel indoor habitats might have a hitherto underestimated impact on the well-being of the increasingly indoor-bound human population. KEY POINTS: Domestic environment harbours a large diversity of microorganisms. Microbiota of water-related indoor habitats mainly originates from tap water. Bathrooms, kitchens and household appliances select for polyextremotolerant species. Many household-related microorganisms are human opportunistic pathogens.

Sepsis in the era of data-driven medicine: personalizing risks, diagnoses, treatments and prognoses

Sepsis is a series of clinical syndromes caused by the immunological response to infection. The clinical evidence for sepsis could typically attribute to bacterial infection or bacterial endotoxins, but infections due to viruses, fungi or parasites could also lead to sepsis. Regardless of the etiology, rapid clinical deterioration, prolonged stay in intensive care units and high risk for mortality correlate with the incidence of sepsis. Despite its prevalence and morbidity, improvement in sepsis outcomes has remained limited. In this comprehensive review, we summarize the current landscape of risk estimation, diagnosis, treatment and prognosis strategies in the setting of sepsis and discuss future challenges. We argue that the advent of modern technologies such as in-depth molecular profiling, biomedical big data and machine intelligence methods will augment the treatment and prevention of sepsis. The volume, variety, veracity and velocity of heterogeneous data generated as part of healthcare delivery and recent advances in biotechnology-driven therapeutics and companion diagnostics may provide a new wave of approaches to identify the most at-risk sepsis patients and reduce the symptom burden in patients within shorter turnaround times. Developing novel therapies by leveraging modern drug discovery strategies including computational drug repositioning, cell and gene-therapy, clustered regularly interspaced short palindromic repeats -based genetic editing systems, immunotherapy, microbiome restoration, nanomaterial-based therapy and phage therapy may help to develop treatments to target sepsis. We also provide empirical evidence for potential new sepsis targets including FER and STARD3NL. Implementing data-driven methods that use real-time collection and analysis of clinical variables to trace, track and treat sepsis-related adverse outcomes will be key. Understanding the root and route of sepsis and its comorbid conditions that complicate treatment outcomes and lead to organ dysfunction may help to facilitate identification of most at-risk patients and prevent further deterioration. To conclude, leveraging the advances in precision medicine, biomedical data science and translational bioinformatics approaches may help to develop better strategies to diagnose and treat sepsis in the next decade.

Pityriasis capitis: Causes, pathophysiology, current modalities, and future approach

BACKGROUND

Pityriasis capitis commonly known as dandruff is one of the most common and widely seen dermatological disease that affects majority of the world population. It is more than superficial flaking, as it leads to significant structural changes in the stratum corneum and inflammatory biomarkers. Various intrinsic and extrinsic factors, such as Malassezia yeast, host epidermal conditions, sebaceous secretion, and abnormal immune responses, are found to contribute to the pathogenesis. Regardless of wide research, detail understanding, and treatment modalities, it still remains to be a cause of concern due to its recurring nature.

AIMS

The objective of this study is to enhance the understanding of its wide causes, pathophysiology, current treatment, and future approach.

METHODS

The article also aims at evaluating various promising anti-dandruff agents that can be further researched to become the leads in anti-dandruff therapy.

RESULTS & CONCLUSION

The article summarizes the current knowledge on dandruff and present new facts and evidences in order to spread awareness, create potential for new herbal treatment options, and effectively control the most commercially exploited scalp disorder.

Stress-Tolerant Yeasts: Opportunistic Pathogenicity Versus Biocontrol Potential

Stress-tolerant fungi that can thrive under various environmental extremes are highly desirable for their application to biological control, as an alternative to chemicals for pest management. However, in fungi, the mechanisms of stress tolerance might also have roles in mammal opportunism. We tested five species with high biocontrol potential in agriculture (Aureobasidium pullulans, Debayomyces hansenii, Meyerozyma guilliermondii, Metschnikowia fructicola, Rhodotorula mucilaginosa) and two species recognized as emerging opportunistic human pathogens (Exophiala dermatitidis, Aureobasidium melanogenum) for growth under oligotrophic conditions and at 37 °C, and for tolerance to oxidative stress, formation of biofilms, production of hydrolytic enzymes and siderophores, and use of hydrocarbons as sole carbon source. The results show large overlap between traits desirable for biocontrol and traits linked to opportunism (growth under oligotrophic conditions, production of siderophores, high oxidative stress tolerance, and specific enzyme activities). Based on existing knowledge and these data, we suggest that oligotrophism and thermotolerance together with siderophore production at 37 °C, urease activity, melanization, and biofilm production are the main traits that increase the potential for fungi to cause opportunistic infections in mammals. These traits should be carefully considered when assessing safety of potential biocontrol agents.

Immunotherapy of Fungal Infections

Fungal organisms are ubiquitous in the environment. Pathogenic fungi, although relatively few in the whole gamut of microbial pathogens, are able to cause disease with varying degrees of severity in individuals with normal or impaired immunity. The disease state is an outcome of the fungal pathogen's interactions with the host immunity, and therefore, it stands to reason that deep/invasive fungal diseases be amenable to immunotherapy. Therefore, antifungal immunotherapy continues to be attractive as an adjunct to the currently available antifungal chemotherapy options for a number of reasons, including the fact that existing antifungal drugs, albeit largely effective, are not without limitations, and that morbidity and mortality associated with invasive mycoses are still unacceptably high. For several decades, intense basic research efforts have been directed at development of fungal immunotherapies. Nevertheless, this approach suffers from a severe bench-bedside disconnect owing to several reasons: the chemical and biological peculiarities of the fungal antigens, the complexities of host-pathogen interactions, an under-appreciation of the fungal disease landscape, the requirement of considerable financial investment to bring these therapies to clinical use, as well as practical problems associated with immunizations. In this general, non-exhaustive review, we summarize the features of ongoing research efforts directed towards devising safe and effective immunotherapeutic options for mycotic diseases, encompassing work on antifungal vaccines, adoptive cell transfers, cytokines, antimicrobial peptides (AMPs), monoclonal antibodies (mAbs), and other agents.

Fungal vaccines and immunotherapeutics

Concomitant with the increased prevalence of immunocompromised persons, invasive fungal infections have become considerably more frequent in the last 50 years. High mortality rates caused by invasive mycoses and high morbidity because of intractable mucosal infections have created an unmet need for innovative prophylactic and therapeutic strategies against fungal pathogens. Several immunotherapeutics and vaccines are in development to address this need, although one has yet to reach the clinic. This review focuses on past and current immunotherapeutic and vaccine strategies being tested to either prevent or treat fungal infections, as well as the challenges associated with their development.

Association of hospital construction with the development of healthcare associated environmental mold infections (HAEMI) in pediatric patients with leukemia

BACKGROUND

Healthcare associated mold infections (HAEMI) increase morbidity and mortality in children with leukemia. Excavation adjacent to Children's Medical Center Dallas (CMCD) April 2006-February 2007 provided an opportunity to determine if excavation adjacent to a hospital building is associated with increased risk of developing HAEMI in children receiving intensive chemotherapy for acute leukemia.

METHODS

Children who began receiving intensive chemotherapy for acute leukemia at CMCD from 2004 to 2008 were identified (n = 275). Exposures to the CMCD campus during intensive chemotherapy and duration of neutropenia per exposure were recorded. Proven, probable, or possible invasive fungal disease (IFD) was classified using EORTC/MSG guidelines. Institutional guidelines categorized mold infections as definite or possible HAEMI. A bivariate time-to-event model compared the association of excavation with HAEMI and yeast infections, controlling for neutropenia.

RESULTS

There were 7,454 CMCD exposures, 1,007 (13.5%) during excavation. Of 50 cases of IFD, 31 were HAEMI. By time-to-event analysis exposure to the CMCD campus during the excavation period was significantly associated with HAEMI (HR = 2.8, P = 0.01) but not yeast infections (HR = 0.75, P = 0.75). Neutropenia was significantly associated with both HAEMI and yeast infections (P < 0.001). Voriconazole prophylaxis did not prevent HAEMI in 42% of the 14 patients with AML who had been receiving this agent.

CONCLUSION

This study is the first to demonstrate an association between exposure to hospital construction that includes excavation and HAEMI in pediatric oncology patients. Since neutropenic patients need protection from aerosolized fungal spores during visits to expanding medical centers, preventive strategies with adherence monitoring need additional study.

Recombinant monovalent llama-derived antibody fragments (VHH) to rotavirus VP6 protect neonatal gnotobiotic piglets against human rotavirus-induced diarrhea

Group A Rotavirus (RVA) is the leading cause of severe diarrhea in children. The aims of the present study were to determine the neutralizing activity of VP6-specific llama-derived single domain nanoantibodies (VHH nanoAbs) against different RVA strains in vitro and to evaluate the ability of G6P[1] VP6-specific llama-derived single domain nanoantibodies (VHH) to protect against human rotavirus in gnotobiotic (Gn) piglets experimentally inoculated with virulent Wa G1P[8] rotavirus. Supplementation of the daily milk diet with 3B2 VHH clone produced using a baculovirus vector expression system (final ELISA antibody -Ab- titer of 4096; virus neutralization -VN- titer of 256) for 9 days conferred full protection against rotavirus associated diarrhea and significantly reduced virus shedding. The administration of comparable levels of porcine IgG Abs only protected 4 out of 6 of the animals from human RVA diarrhea but significantly reduced virus shedding. In contrast, G6P[1]-VP6 rotavirus-specific IgY Abs purified from eggs of hyperimmunized hens failed to protect piglets against human RVA-induced diarrhea or virus shedding when administering similar quantities of Abs. The oral administration of VHH nanoAb neither interfered with the host's isotype profiles of the Ab secreting cell responses to rotavirus, nor induced detectable host Ab responses to the treatment in serum or intestinal contents. This study shows that the oral administration of rotavirus VP6-VHH nanoAb is a broadly reactive and effective treatment against rotavirus-induced diarrhea in neonatal pigs. Our findings highlight the potential value of a broad neutralizing VP6-specific VHH nanoAb as a treatment that can complement or be used as an alternative to the current strain-specific RVA vaccines. Nanobodies could also be scaled-up to develop pediatric medication or functional food like infant milk formulas that might help treat RVA diarrhea.

Group A rotavirus (RVA) is the most common cause of severe diarrhea in human infants worldwide. Live-attenuated rotavirus vaccines are available to prevent rotavirus diarrhea in children, although their efficacy in impoverished areas has been questioned, in addition to not being suitable for children suffering from immune deficiencies. Since no rotavirus-specific treatments are available as an alternative, we investigated llama-derived single-chain antibody fragments (VHH) as preventive therapy and a potential treatment option. Gnotobiotic piglets were chosen as an animal model because their gastrointestinal physiology and mucosal immune system resemble that of human infants. We evaluated the broad neutralizing activity of a VHH clone (3B2) to different genotypes of RVA circulating in humans, and tested the efficacy of oral administration of 3B2 VHH as a functional milk to prevent the diarrhea induced by one of the most prevalent human RVA strains (G1P[8]). Supplementation of the milk diet with 3B2 twice a day for 9 days conferred full protection against rotavirus-associated diarrhea and significantly reduced virus shedding in gnotobiotic piglets experimentally inoculated with a human RVA. This study demonstrates the potential application of VHH to prevent rotavirus-induced diarrhea, and suggests that VHHs should be further investigated as a suitable treatment for gastroenteritis.

LAB/NTAL facilitates fungal/PAMP-induced IL-12 and IFN-γ production by repressing β-catenin activation in dendritic cells

Fungal pathogens elicit cytokine responses downstream of immunoreceptor tyrosine-based activation motif (ITAM)-coupled or hemiITAM-containing receptors and TLRs. The Linker for Activation of B cells/Non-T cell Activating Linker (LAB/NTAL) encoded by Lat2, is a known regulator of ITAM-coupled receptors and TLR-associated cytokine responses. Here we demonstrate that LAB is involved in anti-fungal immunity. We show that Lat2-/- mice are more susceptible to C. albicans infection than wild type (WT) mice. Dendritic cells (DCs) express LAB and we show that it is basally phosphorylated by the growth factor M-CSF or following engagement of Dectin-2, but not Dectin-1. Our data revealed a unique mechanism whereby LAB controls basal and fungal/pathogen-associated molecular patterns (PAMP)-induced nuclear β-catenin levels. This in turn is important for controlling fungal/PAMP-induced cytokine production in DCs. C. albicans- and LPS-induced IL-12 and IL-23 production was blunted in Lat2-/- DCs. Accordingly, Lat2-/- DCs directed reduced Th1 polarization in vitro and Lat2-/- mice displayed reduced Natural Killer (NK) and T cell-mediated IFN-γ production in vivo/ex vivo. Thus our data define a novel link between LAB and β-catenin nuclear accumulation in DCs that facilitates IFN-γ responses during anti-fungal immunity. In addition, these findings are likely to be relevant to other infectious diseases that require IL-12 family cytokines and an IFN-γ response for pathogen clearance.

Universal fungal vaccines: could there be light at the end of the tunnel?

The complex nature of fungal pathogens, the intricate host-pathogen relationship and the health status of subjects in need of antifungal vaccination continue to hamper efforts to develop fungal vaccines for clinical use. That said, the rise of the universal vaccine concept is hoped to revive fungal vaccine research by expanding the pool of vaccine candidates worthy of clinical evaluation. It can do so through antigenic commonality-based screening for vaccine candidates from a wide range of pathogens and by reassessing the sizable collection of already available experimental and approved vaccines. Development of experimental vaccines protective against multiple fungal pathogens is evidence of the utility of this concept in fungal vaccine research. However, universal fungal vaccines are not without difficulties; for instance, development of vaccines with differential effectiveness is an issue that should be addressed. Additionally, rationalizing the development of universal fungal vaccines on health or economic basis could be contentious. Herein, universal fungal vaccines are discussed in terms of their potential usefulness and possible drawbacks.

Immunomodulatory properties of antifungal agents on phagocytic cells

Phagocytic cells, particularly neutrophils and monocytes/macrophages, are the first line and the most effective form of innate host defence against pathogenic fungi. During antifungal therapy these phagocytic cells are also exposed to antifungal agents. In the phagocyte-fungus-antifungal agent interplay, drugs may directly interact with phagocytes through specific pattern recognition receptors, leading to altered antifungal activities. Antifungal agents, through modulation of fungal virulence, may initiate different immune response programs in the phagocytes, leading to antifungal synergism/antagonism or up-regulation of gene expression for a pro-inflammatory response. Additionally, indirect modulation of phagocyte behavior by pretreatment of neutrophils, monocytes, and macrophages with cytokines and exposure to antifungal agents have shown promising findings for combined drug-cytokine therapy that may improve treatment of life-threatening fungal diseases. In this review, we discuss the main in vitro and in vivo immunomodulatory effects of antifungal agents on phagocytes in response to pathogenic fungi, as well as we address underlying immunopharmacologic mechanisms and their potential impact on clinical outcome.

The antimicrobial peptide hLF1-11 drives monocyte-dendritic cell differentiation toward dendritic cells that promote antifungal responses and enhance Th17 polarization

The hLF1-11 peptide comprising the first 11 N-terminal residues of human lactoferrin exerts antimicrobial activity in vivo, enhances the inflammatory response of monocytes and directs monocyte-macrophage differentiation toward cells with enhanced antimicrobial properties. In this study, we investigated the effects of hLF1-11 on human monocyte-dendritic cell (DC) differentiation and subsequent T cell activation. Results revealed that - compared to control (peptide-incubated) DCs - hLF1-11-differentiated DCs displayed enhanced expression of HLA class II antigens and dectin-1, and increased phagocytosis of Candida albicans. In addition, hLF1-11-differentiated DCs produced enhanced amounts of reactive oxygen species, IL-6 and IL-10, but not IL-12p40 and TNF-α, upon stimulation with C. albicans. Moreover, 6-day-cultured hLF1-11-differentiated DCs and control (peptide-incubated) DCs that had been stimulated with a Th17-inducing mix of antigens (including C. albicans) for 24 h were cocultured with autologous CD4+ T cells for 72 h and then the levels of IL-10, IL-17 and IFN-γ production and the percentage of cytokine-producing T cells were assessed. The results revealed that the hLF1-11-differentiated DCs induced an enhanced IL-17, but reduced IFN-γ, production by T cells as compared to control (peptide-incubated) DCs. Collectively, the hLF1-11 peptide drives monocyte-DC differentiation toward DCs that promote antifungal responses and enhance Th17 polarization.

Universal vaccines: shifting to one for many or shooting too high too soon!

Switching from conventional strain-specific vaccines to multi-strain or multi-species universal vaccines is both justified and scientifically merited. Long-term cross-protective universal vaccines eliminate the need for repetitive short-term vaccination campaigns and short-notice vaccine redesign during impending epidemics. They also have the potential to be cost-effective, convenient, and amenable to stockpiling. Ongoing advances in genomics and reverse vaccinology along with the perceived ability of vaccines, if properly formulated, to induce cross-protective adaptive immunity and long-term T cell memory are at the heart of this trend. Consequently, the search for universal vaccines against influenza, HIV, and many other viral, bacterial, and fungal pathogens has intensified in recent years. Currently, several universal influenza vaccines are at different phases of clinical evaluation. That said, vaccine-related differential effectiveness, escape mutants, pathogen strain replacement, limited scope of cross-protective immunity, and diminished potential to reach optimal herd immunity thresholds present serious challenges to the concept and applicability of universal vaccines. Herein, the case for and the case against universal vaccines are investigated to realistically appreciate their prospects of success.

[Spanish Paediatric Infectious Diseases Society consensus document on the treatment of fungal infections based on the immune response]

Despite the emergence of new diagnostic and therapeutic methods, invasive fungal infections are still a major cause of morbidity and mortality in immunocompromised and critical patients. Therefore, adjuvant treatments to the standard antifungal therapy are being investigated, with immunity-based therapy being one of the most important. Both immunomodulatory (dendritic and T cells transfusions, colony stimulating factors, interferón-gamma, interleukin 12, fungal vaccines, transfer factors and certain drugs such as chloroquine) and immunotherapeutic modalities (granulocyte transfusions, monoclonal antibodies and intravenous immunoglobulin) have been described. This document aims to summarise currently available data on immunity-based therapy of fungal infections and to provide basic knowledge on the immune response to fungal infections. This helps to understand how, in selected cases, immunity-based therapy may improve the response to standard antifungal treatment. The potential indications of immunity-based therapy in the paediatric patient are reviewed, although there is still a lack of scientific evidence for its use in children.