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Picture yourself as a researcher in immunology. To begin your project, you ask a question: Do CD8 T cells require antigen to maintain a memory response? This question is of prime importance to numerous medical fields. In chronologic order, you digest the literature, but unfortunately, you hit a major stumbling block in the 1990s. The crux of the problem is that which so often happens in science: two well-recognized, capable groups emerge with diametrically opposed conclusions, leaving you pondering which set of wellcontrolled data to believe. Fortunately, years later, a surprising group of articles sheds light on this mystery and subtly reconciles these two positions.

Conventional dendritic cells (cDCs) generate protective cytotoxic T lymphocyte (CTL) responses against extracellular pathogens and tumors. This is achieved through a process known as cross-presentation (XP), and, despite its biological importance, the mechanism(s) driving XP remains unclear. Here, we show that a cDC-specific pore-forming protein called apolipoprotein L 7C (APOL7C) is up-regulated in response to innate immune stimuli and is recruited to phagosomes. Association of APOL7C with phagosomes led to phagosomal rupture and escape of engulfed antigens to the cytosol, where they could be processed via the endogenous MHC class I antigen processing pathway. Accordingly, mice deficient in APOL7C did not efficiently prime CD8 + T cells in response to immunization with bead-bound and cell-associated antigens. Together, our data indicate the presence of dedicated apolipoproteins that mediate the delivery of phagocytosed proteins to the cytosol of activated cDCs to facilitate XP.

Cryptococcosis is a major worldwide disseminated invasive fungal infection. Cryptococcosis, particularly in its most lethal manifestation of cryptococcal meningitis, accounts for substantial mortality and morbidity. The breadth of the clinical cryptococcosis syndromes, the different patient types at-risk and affected, and the vastly disparate resource settings where clinicians practice pose a complex array of challenges. Expert contributors from diverse regions of the world have collated data, reviewed the evidence, and provided insightful guideline recommendations for health practitioners across the globe. This guideline offers updated practical guidance and implementable recommendations on the clinical approaches, screening, diagnosis, management, and follow-up care of a patient with cryptococcosis and serves as a comprehensive synthesis of current evidence on cryptococcosis. This Review seeks to facilitate optimal clinical decision making on cryptococcosis and addresses the myriad of clinical complications by incorporating data from historical and contemporary clinical trials. This guideline is grounded on a set of core management principles, while acknowledging the practical challenges of antifungal access and resource limitations faced by many clinicians and patients. More than 70 societies internationally have endorsed the content, structure, evidence, recommendation, and pragmatic wisdom of this global cryptococcosis guideline to inform clinicians about the past, present, and future of care for a patient with cryptococcosis., Competing Interests: Declaration of interests AA reports grants from the Agence Nationale de la Recherche; serving as a consultant to Gilead Sciences; receiving speaking honoraria from Gilead Sciences and PR Edition; travel support from Gilead sciences and Pfizer; and patents with the Institut Pasteur. J-WA reports grants or contracts from WHO (fungal priority pathogens list) and receipt of equipment and materials from the Westmead Hospital Foundation. JB reports support from the Australian National Health and Medical Research Council and receipt of honoraria from Gilead. TAB reports a personal research fellowship from Gilead Sciences; investigator-led research grant from Pfizer; lecture honoraria and participation in advisory boards for Gilead Sciences, Mundipharma, and Pfizer; and participation in the Trial Steering Committee for a phase 2 trial of inhaled opelconazole (Pulmocide). FC reports speaker honoraria from, and being part of, an advisory board for Pfizer and United Medical. CCC reports receipt of an Early Career Fellowship from the Australian National Health and Medical Research Foundation, receipt of a speaker travel support for IDweek 2024, being a principal investigator in an early phase clinical trial unit, and was a recipient of the Australian National Health and Medical Research Council Early Career Fellowship (APP 1092160). MC reports grants from Cidara, F2G, Pfizer, and Janssen; receipt of honoraria from Pfizerm MSD and Gilead; and travel support from Pfizer. SCC reports untied educational grants from MSD Australia and F2G and is on the antifungal advisory boards of MSD Australia, Gilead Sciences, and F2G. OAC reports grants or contracts from BMBF, Cidara, EU-DG RTD (101037867), F2G, Gilead, MedPace, MSD, Mundipharma, Octapharma, Pfizer, and Scynexis; consulting fees from AbbVie, AiCuris, Biocon, Cidara, Gilead, IQVIA, Janssen, Matinas, MedPace, Menarini, Moderna, Molecular Partners, MSG-ERC, Noxxon, Octapharma, Pfizer, PSI, Scynexis, and Seres; honoraria for lectures from Abbott, AbbVie, Al-Jazeera Pharmaceuticals, Hikma, Gilead, Grupo Biotoscana/United Medical/Knight, MedScape, MedUpdate, Merck/MSD, Noscendo, Pfizer, Shionogi, and streamedup!; payment for expert testimony from Cidara; participation on a data safety monitoring board or advisory board from Boston Strategic Partners, Cidara, IQVIA, Janssen, MedPace, PSI, Pulmocide, Shionogi, and The Prime Meridian Group; a patent at the German Patent and Trade Mark Office (DE 10 2021 113 007·7); stocks from CoRe Consulting and EasyRadiology; other interests from Wiley; support from the German Federal Ministry of Research and Education; and funding by the Deutsche Forschungsgemeinschaft under Germany's Excellence Strategy (Cologne Cluster of Excellence on Cellular Stress Responses in Aging-associated Diseases, EXC 2030—390661388). J-PG reports speaker honoraria from Gilead, MundiPharma, and Pfizer. NPG reports grants from National Institutes of Health (USA), National Institute of Health and Care Research (UK), Medical Research Council (MRC; UK), Centers for Disease Control and Prevention (CDC; USA), and National Health Laboratory Service Research Trust (South Africa); participation in the ACACIA trial as part of the data safety monitoring board, project committee of DREAMM, project advisory committee for 5FC Crypto, and leadership roles in the Federation of Infectious Diseases Societies of Southern Africa. AHG reports grants from Gilead Sciences; personal fees from Amplyx, Astellas, Basilea, F2G, Gilead Sciences, Merck Sharp & Dohme, Mundipharma, Pfizer, and Scynexis; speaker honoraria from Gilead Sciences and MSD; and participation in an advisory board for Astellas, Mundipharma, Partner Therapeutics, and Pfizer. FH reports grants from Health Holland and European Society for Clinical Microbiology and Infectious Diseases; leadership roles as treasurer of the Netherlands Society for Medical Mycology, Chair of the Division Microbial Genomics of the Royal Netherlands Society for Microbiology, Vice-President International Society for Human and Animal Mycology (ISHAM); and receipt of evaluation kits from Bruker and Pathonostics. TSH reports receipt of an investigator award from Gilead Sciences, honoraria from Pfizer and Gilead Sciences, and participation in a data safety monitoring board or advisory board for Viamet and F2G. MH reports receipt of an European and Developing Countries Clinical Trials Partnership. JNJ reports support from the National Institute for Health Research; grants from European and Developing Countries Clinical Trials Partnership, joint global health trials (Wellcome Trust, MRC, and UK aid) and CDC; speaker fees from Gilead Sciences; participation on a data safety and monitoring board for the HARVEST, ARTIST, CASTLE, and ACACIA trials. GJ reports travel support to attend a meeting at ISHAM. NK was a speaker and advisor for Gilead Sciences, Merck/MSD, and Pfizer and a speaker for Astellas. MSL reports support from the Division of Intramural Research, National Institute of Allergy and Infectious Diseases (NIAID), and National Institutes of Health (NIH). OL reports receipt of consulting fees and honoraria from Gilead Science and patents with INSERM APHP. OMM reports travel support for ISHAM meeting in India and being the country ambassador for Kenya for ISHAM. BJM reports being chair of the Australia and New Zealand Paediatric Infectious Diseases Group. DBM reports leadership role in the Crypto Meningitis advocacy group. RO reports receiving research and educational grant funding from Gilead Sciences, CDC Atlanta, and Pfizer Specialties and travel support from the CDC foundation. PGP reports grants from Mayne, Astellas, Scynexis, and Cidara and receipt of consulting fees from F2G and Cidara. AKP reports speaker honoraria for Gilead Science, Pfizer India, and Intas pharmaceutical. JRP reports grants from NIH, Appili, and Sfunga; royalties from Up-To-Date; and participation on a data safety monitoring board or advisory board from Pulmocide, EFFECT trial, and IMPRINT trial. FQ-TF reports receipt of speaker honoraria from Pfizer and United Medical, travel support and laboratory diagnostic kits from IMMY, and leadership roles in Infocus Latin America. JS-G reports speaker honoraria from Gilead and Pfizer and is on an advisory committee for Pfizer. AS reports grants from Astellas and receiving consulting fees from Scynexis. RSp has received speaker honoraria from Pfizer and reports being chair of Young European Confederation of Medical Mycology. TT reports receipt of honoraria from Pfizer, MSD, Asahikasei pharma, and Sumitomo pharma. AW reports a grant from UK Research and Innovation; receipt of consultant fees from Gilead and MundiPharma; speaker fees from F2G and Gilead; and participation as a data safety monitoring board member for the RECOVERY trial. All declarations are outside the submitted work. All other authors declare no competing interests., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Intracavitary pulmonary aspergilloma is a persistent and life-threatening infection that carries a mortality rate of up to 15%. It occurs when Aspergillus species gain entry to an existing lung cavity. In the absence of definitive treatment, patients may succumb to severe complications such as massive hemoptysis, cachexia, or secondary infections. Aspergillomas often show limited response to antifungal medications, mainly due to insufficient drug concentrations within the cavities. Surgery is frequently the preferred treatment option, but it poses significant risks, and many individuals are ineligible due to underlying health issues. We present the most extensive non-surgical fungal ball cohort to date, managed using an innovative multimodal strategy that combines antifungal therapy before and after bronchoscopic debulking. This was a cross-sectional observational study. For those who cannot undergo surgery, our medical center has pioneered a multimodal approach to aspergilloma resection. This approach combines bronchoscopic endoscopy with antifungal therapy and has been applied successfully to more than 18 patients that are presented in this series. The median age of the cohort was 58 years (range: 32-73), with an equal sex distribution. The mean percent predicted FEV 1 was 65.3%. The mean follow-up duration was 3.6 years (range: 0.5-10 years). The cohort receiving antifungals systematically prior to debridement showed a reduction of the pre-existing cavity (40.38 mm versus 34.02 mm, p  = 0.021). Across the 18 patients during the follow-up period, 94% remained recurrence-free (defined by symptoms and radiology). Our study fills a critical knowledge gap regarding the significance of initiating antifungal treatment before bronchoscopic debulking and presents a viable approach in these cases for which there is a current unmet therapeutic need.

Prophylactic vaccination strategies designed to prevent diseases caused by pathogens using the phagolysosome of innate immune cells as a site of intracellular replication and survival have been largely ineffective. These include Mycobacterium tuberculosis (Mtb), Leishmania spp., and Cryptococcus spp. These failed strategies have traditionally targeted CD4 + T helper (Th) 1 cell-mediated immune memory, deeming it crucial for vaccine efficacy. This failure warrants an investigation of alternative mediators of protection. Here, we suggest three novel approaches to activate phagocytic cells prior to or at the time of infection. We hypothesize that preventing the formation of the pathogen niche within the phagolysosome is essential for preventing disease, and a greater emphasis on the timing of phagocyte activation should generate more effective prophylactic treatment options., Competing Interests: Declaration of interests No interests are declared., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Rationale: The pathobiology of Staphylococcus aureus in non-cystic fibrosis bronchiectasis (nCFB) is poorly defined. When present at high density or "inoculum," some methicillin-sensitive S. aureus (MSSA) can inefficiently degrade antistaphylococcal β-lactam antibiotics via BlaZ penicillinases (termed the "inoculum effect" [IE]). Given the high burden of organisms in bronchiectatic airways, this is particularly relevant. Objectives: Drawing from a prospectively collected biobank, we sought to understand the prevalence, natural history, potential for transmission, and antibiotic resistance profiles among nCFB-derived MSSA isolates. Methods: All individuals attending a regional consultancy nCFB clinic with sputum collected between 1981 and 2017 were considered, and those with one or more S. aureus -positive cultures composed the cohort. Each individual's most recent biobank isolate was subjected to whole-genome sequencing (including the blaZ gene), antibacterial susceptibility testing, and comparative β-lactam testing at standard (5 × 10 5  colony-forming unit [cfu]/ml) and high (5 × 10 7  cfu/ml) inocula to assess for the IE and pronounced IE. Results: Seventy-four (35.4%) of 209 individuals had one or more sputum samples with S. aureus (68 MSSA, 6 methicillin-resistant S. aureus ). Those with S. aureus infection were more likely to be female. Among 60 of 74 MSSA isolates subjected to whole-genome sequencing, no evidence of transmission was identified, although specific multilocus sequence typing types were prevalent, including ST-1, ST-15, ST-30, and ST-45. Antibiotic resistance was uncommon, except for macrolides (∼20%). Among the 60 MSSA samples, the prevalence of IE and pronounced IE was observed to be drug specific: meropenem (0% and 0%, respectively), cefepime (3% and 5%, respectively), ceftazidime (8% and 0%, respectively), cloxacillin (12% and 0%, respectively), cefazolin (23% and 0%, respectively), and piperacillin-tazobactam (37% and 17%, respectively). The cefazolin IE was associated with blaZ type A ( P  < 0.01) and ST-30 ( P  < 0.01), whereas the piperacillin-tazobactam IE was associated with type C blaZ ( P  < 0.001) and ST-15 ( P  < 0.05). Conclusions: S. aureus infection was common, although no evidence of transmission was apparent in our nCFB cohort. Although routine susceptibility testing did not identify significant resistance, inoculum-related resistance was found to be relevant for commonly used nCFB antibiotics, including cefazolin and piperacillin-tazobactam. Given previous associations between IEs and negative patient outcomes, further work is warranted to understand how this phenotype impacts nCFB disease progression.

Pseudomonas aeruginosa is an opportunistic pathogen that often infects individuals with the genetic disease cystic fibrosis, and contributes to airway blockage and loss of lung function. Natural killer (NK) cells are cytotoxic, granular lymphocytes that are part of the innate immune system. NK cell secretory granules contain the cytolytic proteins granulysin, perforin and granzymes. In addition to their cytotoxic effects on cancer and virally infected cells, NK cells have been shown to play a role in an innate defense against microbes, including bacteria. However, it is not known if NK cells kill extracellular P. aeruginosa or how bacterial killing might occur at the molecular level. Here we show that NK cells directly kill extracellular P. aeruginosa using NK effector molecules. Live cell imaging of a co-culture of YT cells, a human NK cell line, and GFP-expressing P. aeruginosa in the presence of the viability dye propidium iodide demonstrated that YT cell killing of P. aeruginosa is contact-dependent. CRISPR knockout of granulysin or perforin in YT cells had no significant effect on YT cell killing of P. aeruginosa. Pre-treatment of YT and NK cells with the serine protease inhibitor 3,4-dichloroisocoumarin (DCI) to inhibit all granzymes, resulted in an inhibition of killing. Although singular CRISPR knockout of granzyme B or H had no effect, knockout of both in YT cells completely abrogated killing of P. aeruginosa in comparison to wild type YT cell controls. Nitrocefin assays suggest that the bacterial membrane is damaged. Inhibition of killing by antioxidants suggest that ROS are required for the bactericidal mode-of-action. Taken together, these results identify that NK cells kill P. aeruginosa through a membrane damaging, contact-dependent process that requires granzyme induced ROS production, and moreover, that granzyme B and H are redundant in this killing process., Competing Interests: The authors have declared no competing interests exist.

Humans have developed complex immune systems that defend against invading microbes, including fungal pathogens. Many highly specialized cells of the immune system share the ability to store antimicrobial compounds in membrane bound organelles that can be immediately deployed to eradicate or inhibit growth of invading pathogens. These membrane-bound organelles consist of secretory vesicles or granules, which move to the surface of the cell, where they fuse with the plasma membrane to release their contents in the process of degranulation. Lymphocytes, macrophages, neutrophils, mast cells, eosinophils, and basophils all degranulate in fungal host defence. While anti-microbial secretory vesicles are shared among different immune cell types, information about each cell type has emerged independently leading to an uncoordinated and confusing classification of granules and incomplete description of the mechanism by which they are deployed. While there are important differences, there are many similarities in granule morphology, granule content, stimulus for degranulation, granule trafficking, and release of granules against fungal pathogens. In this review, we describe the similarities and differences in an attempt to translate knowledge from one immune cell to another that may facilitate further studies in the context of fungal host defence.

Cryptococcus gattii is a major cause of life-threatening mycosis in immunocompetent individuals and responsible for the ongoing epidemic outbreak of cryptococcosis in the Pacific Northwest of North America. This deadly fungus is known to evade important host immune responses, including dendritic cell (DC) maturation and concomitant T cell immunity, via immune evasion mechanisms that remain unclear. Here, we demonstrate that primary human DCs phagocytose C. gattii but the maturation of phagosomes to phagolysosomes was blocked as a result of sustained filamentous actin (F-actin) that entrapped and concealed the phagosomes from recognition. Superresolution structured illumination microscopy (SR-SIM) revealed that the persistent phagosomal F-actin formed a cage-like structure that sterically hindered and functionally blocked the fusion of lysosomes. Blocking lysosome fusion was sufficient to inhibit phagosomal acidification and subsequent intracellular fungal killing by DCs. Retention of phagosomal F-actin by C. gattii also caused DC immunoparalysis. Disrupting the retained F-actin cage with cytochalasin D not only restored DC phagosomal maturation but also promoted DC costimulatory maturation and robust T cell activation and proliferation. Collectively, these results reveal a unique mechanism of DC immune evasion that enhances intracellular fungal pathogenicity and may explain suppressed cell-mediated immunity. IMPORTANCE Cryptococcus yeast species typically display characteristics of opportunistic pathogens, with the exception of C. gattii , which can cause life-threatening respiratory and disseminated brain infections in otherwise healthy people. The pathogenesis of C. gattii is not well understood, but an important characteristic is that C. gattii is capable of evading host cell-mediated immune defenses initiated by DCs. Here, we report that when virulent C. gattii becomes ingested by a DC, the intracellular compartment containing the fungi is covered by a persistent protein cage structure consisting of F-actin. This F-actin cage acts as a barrier to prevent interaction with other intracellular compartments, and as a result, the DC fails to kill the fungi and activate important cell-mediated immune responses. We propose that this unique immune evasion mechanism permits C. gattii to remain unchallenged within host cells, leading to persistent infection.

Objective: To describe the burden of pneumococcal disease and associated risk factors in the Canadian adult population, delineate available pneumococcal vaccines and associated efficacy and effectiveness data, and review current pneumococcal vaccine recommendations and community-acquired pneumonia (CAP) prevention strategies in Canada., Quality of Evidence: Pneumococcal vaccination guidelines from the Canadian National Advisory Committee on Immunization in 2013 and 2016 constitute level III evidence for CAP prevention in the Canadian adult population., Main Message: It is recommended that immunosuppressed adults of all ages receive the 13-valent pneumococcal conjugate vaccine (PCV13) (grades A and B recommendations). In 2016, the National Advisory Committee on Immunization also recommended that all adults aged 65 years and older receive PCV13 (grade A recommendation) on an individual basis, followed by the 23-valent pneumococcal polysaccharide vaccine (grade B recommendation). This update is based on a large clinical study that demonstrated PCV13 efficacy against vaccine-type CAP in this population., Conclusion: Physicians should focus on improving pneumococcal vaccination rates among adults, which remain low. Vaccination with PCV13 should also be considered for adults with chronic conditions, whose baseline risk is often higher than that for healthy individuals aged 65 years and older., (Copyright© the College of Family Physicians of Canada.)

It is now evident that NK cells kill bacteria, fungi, and parasites in addition to tumor and virus-infected cells. In addition to a number of recent publications that have identified the receptors and ligands, and mechanisms of cytotoxicity, new insights are reflected in the reports from researchers all over the world at the 17th Meeting of the Society for Natural Immunity held in San Antonio, TX, USA from May 28 through June 1, 2018. We will provide an overview of the field and discuss how the presentations at the meeting might shape our knowledge and future directions in the field., (©2019 Society for Leukocyte Biology.)

Burkholderia cepacia complex (Bcc), which includes B. cenocepacia and B. multivorans, pose a life-threatening risk to patients with cystic fibrosis. Eradication of Bcc is difficult due to the high level of intrinsic resistance to antibiotics, and failure of many innate immune cells to control the infection. Because of the pathogenesis of Bcc infections, we wondered if a novel mechanism of microbial host defense involving direct antibacterial activity by natural killer (NK) cells might play a role in the control of Bcc. We demonstrate that NK cells bound Burkholderia, resulting in Src family kinase activation as measured by protein tyrosine phosphorylation, granule release of effector proteins such as perforin and contact-dependent killing of the bacteria. These studies provide a means by which NK cells could play a role in host defense against Bcc infection., (© The Japanese Society for Immunology. 2019. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

A diverse microbiota exists within the airways of individuals with non-cystic fibrosis bronchiectasis (nCFB). How the lung microbiome evolves over time, and whether changes within the microbiome correlate with future disease progression is not yet known. We assessed the microbial community structure of 133 serial sputa and subsequent disease course of 29 nCFB patients collected over a span of 4-16 years using 16S rRNA paired-end sequencing. Interestingly, no significant shifts in the microbial community of individuals were observed during extended follow-up suggesting the microbiome remains relatively stable over prolonged periods. Samples that were Pseudomonas aeruginosa culture positive displayed markedly different microbial community structures compared to those that were positive for Haemophilus influenzae. Importantly, patients with sputum of lower microbial community diversity were more likely to experience subsequent lung function decline as defined by annual change in ≥-1 FEV 1 % predicted. Shannon diversity values <1 were more prevalent in patients with FEV 1 decline (P = 0.002). However, the relative abundance of particular core microbiota constituents did not associate with risk of decline. Here we present data confirming that the microbiome of nCFB individuals is generally stable, and that microbiome-based measurements may have a prognostic role as biomarkers for nCFB.

Cryptococcus neoformans is a fungal pathogen that causes fatal meningitis and pneumonia. During host defense to Cryptococcus , NK cells directly recognize and kill C. neoformans using cytolytic degranulation analogous to killing of tumor cells. This fungal killing requires independent activation of Src family kinase (SFK) and Rac1-mediated pathways. Recognition of C. neoformans requires the natural cytotoxicity receptor, NKp30; however, it is not known whether NKp30 activates both signal transduction pathways or whether a second receptor is involved in activation of one of the pathways. We used primary human NK cells and a human NK cell line and found that NKp30 activates SFK → PI3K but not Rac1 cytotoxic signaling, which led to a search for the receptor leading to Rac1 activation. We found that NK cells require integrin-linked kinase (ILK) to activate Rac1 for effective fungal killing. This observation led to our identification of β1 integrin as an essential anticryptococcal receptor. These findings demonstrate that multiple receptors, including β1 integrins and NKp30 and their proximal signaling pathways, are required for recognition of Cryptococcus , which activates a central cytolytic antimicrobial pathway leading to fungal killing., (Copyright © 2018 by The American Association of Immunologists, Inc.)

Cryptococcus is the most important cause of fungal meningitis in immunocompromised individuals. Host defense against Cryptococcus involves direct killing by NK cells. That NK cells from HIV-infected patients fail to polarize perforin to the microbial synapse and kill C. neoformans led us to explore the mechanisms used to reposition and polarize the cytolytic granules to the synapse. Using live-cell imaging, we observed microtubule and granule movements in response to Cryptococcus that revealed a kinesin-dependent event. Eg5-kinesin bound to perforin-containing granules and was required for association with the microtubules. Inhibition of Eg5-kinesin abrogated dynein-dependent granule convergence to the MTOC and granule and MTOC polarization to the synapse and suppressed NK cell killing of Cryptococcus. In contrast, Eg5-kinesin was dispensable for tumor killing. This reveals an alternative mechanism of MTOC repositioning and granule polarization, not used in tumor cytotoxicity, in which Eg5-kinesin is required to initiate granule movement, leading to microbial killing., (Copyright © 2018 The Authors. Published by Elsevier Inc. All rights reserved.)

The natural history and epidemiology of Pseudomonas aeruginosa infections in non-cystic fibrosis (non-CF) bronchiectasis is not well understood. As such it was our intention to determine the evolution of airway infection and the transmission potential of P. aeruginosa in patients with non-CF bronchiectasis. A longitudinal cohort study was conducted from 1986-2011 using a biobank of prospectively collected isolates from patients with non-CF bronchiectasis. Patients included were ≥18 years old and had ≥2 positive P. aeruginosa cultures over a minimum 6-month period. All isolates obtained at first and most recent clinical encounters, as well as during exacerbations, that were morphologically distinct on MacConkey agar were genotyped by pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST). A total of 203 isolates from 39 patients were analysed. These were compared to a large collection of globally epidemic and local CF strains, as well as non-CF isolates. We identified four patterns of infection in non-CF bronchiectasis including: 1) persistence of a single strain (n=26; 67%); 2) strain displacement (n=8; 20%); 3) temporary disruption (n=3; 8%); and 4) chaotic airway infection (n=2; 5%). Patterns of infection were not significant predictors of rates of lung function decline or progression to end-stage disease and acquisition of new strains did not associate with the occurrence of exacerbations. Rarely, non-CF bronchiectasis strains with similar pulsotypes were observed in CF and non-CF controls, but no CF epidemic strains were observed. While rare shared strains were observed in non-CF bronchiectasis, whole-genome sequencing refuted patient-patient transmission. We observed a higher incidence of strain-displacement in our patient cohort compared to those observed in CF studies, although this did not impact on outcomes., Competing Interests: Conflict of interest: R. Somayaji has received research fellowship funding from Cystic Fibrosis Canada, Alberta Innovates and the Canadian Institutes of Health Research, and grants from Cystic Fibrosis Canada, the Canadian Institute of Health Research and the Royal College of Physicians and Surgeons outside the submitted work. M.D. Parkins has received research funding from Cystic Fibrosis Canada, the Canadian Institute of Health Research, the Lung Association of Alberta and the Northwest Territories, Gilead Sciences, The University of Calgary and Calgary Laboratory Services.

Background: Variation in hospital management of patients with acute exacerbation of chronic obstructive pulmonary disease (AECOPD) may prolong length of stay, increasing the risk of hospital-acquired complications and worsening quality of life. We sought to determine whether an evidence-based computerized AECOPD admission order set could improve quality and reduce length of stay., Methods: The order set was designed by a provincial COPD working group and implemented voluntarily among three physician groups in a Canadian tertiary-care teaching hospital. The primary outcome was length of stay for patients admitted during order set implementation period, compared to the previous 12 months. Secondary outcomes included length of stay of patients admitted with and without order set after implementation, all-cause readmissions, and emergency department visits., Results: There were 556 admissions prior to and 857 admissions after order set implementation, for which the order set was used in 47%. There was no difference in overall length of stay after implementation (median 6.37 days (95% confidence interval 5.94, 6.81) pre-implementation vs. 6.02 days (95% confidence interval 5.59, 6.46) post-implementation, p = 0.26). In the post-implementation period, order set use was associated with a 1.15-day reduction in length of stay (95% confidence interval - 0.5, - 1.81, p = 0.001) compared to patients admitted without the order set. There was no difference in readmissions., Conclusions: Use of a computerized guidelines-based admission order set for COPD exacerbations reduced hospital length of stay without increasing readmissions. Interventions to increase order set use could lead to greater improvements in length of stay and quality of care.

Cryptococcal disease, caused by Cryptococcus neoformans and Cryptococcus gattii, is associated with significant morbidity and mortality but limited data exist on its incidence and impact. A study utilizing the Nationwide Inpatient Sample from 2000 to 2007 to examine the epidemiology and impact of cryptococcal disease in the United States was undertaken. The International Classification of Diseases 9th Version code was used to identify hospital discharges with diagnosis of Cryptococcus (117.5). Our primary outcome was the incidence rate of cryptococcal admissions. The impact of AIDS, age, and sex on hospitalization rates, mortality, and costs was assessed. The results showed that a total of 10,077 hospitalizations for cryptococcosis occurred corresponding to a weighted estimate of 49,010 cases. The median age was 43 years (interquartile range 34-54), and 26% were female. Approximately 64% of cases occurred in persons with AIDS. Although rates declined overall, age-adjusted rates were significantly higher in males with AIDS than in uninfected persons (p < 0.001). The mortality rate decreased but was greater in HIV-uninfected versus infected cohorts (12% versus 10%, p < 0.001). Conversely, hospital costs were greater in persons with AIDS ($40,671 versus $40,096, p=0.02). Although cryptococcal disease rates are decreasing over time, the associated mortality and costs remain concerning.

Natural killer (NK) cells use the activating receptor NKp30 as a microbial pattern-recognition receptor to recognize, activate cytolytic pathways, and directly kill the fungi Cryptococcus neoformans and Candida albicans. However, the fungal pathogen-associated molecular pattern (PAMP) that triggers NKp30-mediated killing remains to be identified. Here we show that β-1,3-glucan, a component of the fungal cell wall, binds to NKp30. We further demonstrate that β-1,3-glucan stimulates granule convergence and polarization, as shown by live cell imaging. Through Src Family Kinase signaling, β-1,3-glucan increases expression and clustering of NKp30 at the microbial and NK cell synapse to induce perforin release for fungal cytotoxicity. Rather than blocking the interaction between fungi and NK cells, soluble β-1,3-glucan enhances fungal killing and restores defective cryptococcal killing by NK cells from HIV-positive individuals, implicating β-1,3-glucan to be both an activating ligand and a soluble PAMP that shapes NK cell host immunity.

Candida albicans bloodstream infection causes fungal septicaemia and death in over half of afflicted patients. Polymorphonuclear leukocytes (PMN) mediate defense against invasive candidiasis, but their role in protection versus tissue injury and sepsis is unclear. We observe PMN intravascular swarming and subsequent clustering in response to C. albicans yeast in a lethal septic mouse and human pulmonary circulation model. Live C. albicans sequester to the endothelium and are immediately captured by complement-dependent PMN chemotaxis, which is required for host survival. However, complement activation also leads to Leukotriene B4 (LTB4)-mediated intravascular PMN clustering and occlusion, resulting in capillaritis with pulmonary hemorrhage and hypoxemia. This clustering is unique to fungi and triggered by fungal cell wall components. PMN clustering is absent in mice lacking LTB4-receptor, and capillaritis is attenuated upon pharmacological LTB4 blockade without affecting phagocytosis. Therefore, therapeutically disrupting infection-induced capillaritis may limit organ injury without impairing host defense during fungal sepsis., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Cryptococcus is among the most common invasive fungal pathogens globally and is one of the leading causes of acquired immunodeficiency virus-related deaths. Cryptococcus neoformans and Cryptococcus gattii are the most clinically relevant species and account for most cryptococcal disease. Pulmonary manifestations can range from mild symptoms to life-threatening infection. Treatment is tailored based on the severity of pulmonary infection, the presence of disseminated or central nervous system disease, and patient immune status. Amphotericin B and flucytosine followed by fluconazole remain the standard agents for the treatment of severe cryptococcal infection., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Cyclic GMP-AMP synthase (cGAS) is a newly identified DNA sensor that recognizes foreign DNA, including the genome of herpes simplex virus 1 (HSV-1). Upon binding of viral DNA, cGAS produces cyclic GMP-AMP, which interacts with and activates stimulator of interferon genes (STING) to trigger the transcription of antiviral genes such as type I interferons (IFNs), and the production of inflammatory cytokines. HSV-1 UL24 is widely conserved among members of the herpesviruses family and is essential for efficient viral replication. In this study, we found that ectopically expressed UL24 could inhibit cGAS-STING-mediated promoter activation of IFN-β and interleukin-6 (IL-6), and UL24 also inhibited interferon-stimulatory DNA-mediated IFN-β and IL-6 production during HSV-1 infection. Furthermore, UL24 selectively blocked nuclear factor κB (NF-κB) but not IFN-regulatory factor 3 promoter activation. Coimmunoprecipitation analysis demonstrated that UL24 bound to the endogenous NF-κB subunits p65 and p50 in HSV-1-infected cells, and UL24 was also found to bind the Rel homology domains (RHDs) of these subunits. Furthermore, UL24 reduced the tumor necrosis factor alpha (TNF-α)-mediated nuclear translocation of p65 and p50. Finally, mutational analysis revealed that the region spanning amino acids (aa) 74 to 134 of UL24 [UL24(74-134)] is responsible for inhibiting cGAS-STING-mediated NF-κB promoter activity. For the first time, UL24 was shown to play an important role in immune evasion during HSV-1 infection. IMPORTANCE NF-κB is a critical component of the innate immune response and is strongly induced downstream of most pattern recognition receptors (PRRs), leading to the production of IFN-β as well as a number of inflammatory chemokines and interleukins. To establish persistent infection, viruses have evolved various mechanisms to counteract the host NF-κB pathway. In the present study, for the first time, HSV-1 UL24 was demonstrated to inhibit the activation of NF-κB in the DNA sensing signal pathway via binding to the RHDs of the NF-κB subunits p65 and p50 and abolishing their nuclear translocation., (Copyright © 2017 American Society for Microbiology.)

Background: Intracavitary pulmonary aspergilloma is a chronic, debilitating fungal infection. Without definitive therapy, death can occur from massive hemoptysis, cachexia, or secondary infection. Although surgical resection is the standard therapy, it is not possible for many patients owing to poor pulmonary function or medical comorbidities. Aspergilloma removal through bronchoscopy is an important alternative therapy that may be available in select cases., Methods: We retrospectively reviewed all cases referred to the University of Calgary Interventional Pulmonary Service for transbronchial removal of intracavitary aspergilloma from January 1, 2009, to January 1, 2014., Results: Ten patients with intracavitary pulmonary aspergilloma were identified. In 3 patients, the aspergilloma cavity was not accessible by bronchoscopy. Successful removal of the aspergilloma with symptom improvement or resolution was achieved in 6 of 7 cases. One of the patients was lost to follow-up. Minor hypoxia lasting 12 to 72 hours was observed in 5 cases. Severe sepsis requiring an extended critical care unit stay occurred in 1 case. Follow-up ranged from 9 months to 5 years., Conclusions: Although not without risk of minor hypoxia and possible sepsis, for carefully selected patients, bronchoscopic removal of symptomatic intracavitary pulmonary aspergilloma may be an alternative therapy to surgical resection for this life-threatening disease., (Copyright © 2017 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.)

Natural killer (NK) cells kill or inhibit the growth of a number of fungi including Cryptococcus, Candida, Aspergillus, Rhizopus , and Paracoccidioides . Although many fungi are not dangerous, invasive fungal pathogens, such as Cryptococcus neoformans , cause life-threatening disease in individuals with impaired cell-mediated immunity. While there are similarities to cell-mediated killing of tumor cells, there are also important differences. Similar to tumor killing, NK cells directly kill fungi in a receptor-mediated and cytotoxic granule-dependent manner. Unlike tumor cell killing where multiple NK cell-activating receptors cooperate and signal events that mediate cytotoxicity, only the NKp30 receptor has been described to mediate signaling events that trigger the NK cell to mobilize its cytolytic payload to the site of interaction with C. neoformans and Candida albicans , subsequently leading to granule exocytosis and fungal killing. More recently, the NKp46 receptor was reported to bind Candida glabrata adhesins Epa1, 6, and 7 and directly mediate fungal clearance. A number of unanswered questions remain. For example, is only one NK cell-activating receptor sufficient for signaling leading to fungal killing? Are the signaling pathways activated by fungi similar to those activated by tumor cells during NK cell killing? How do the cytolytic granules traffic to the site of interaction with fungi, and how does this process compare with tumor killing? Recent insights into receptor use, intracellular signaling and cytolytic granule trafficking during NK cell-mediated fungal killing will be compared to tumor killing, and the implications for therapeutic approaches will be discussed.

Natural killer (NK) cells are an important contributor to innate host defense because of their role in direct microbial recognition and killing. Vitenshtein et al. make an important contribution by demonstrating that NK cells kill Candida glabrata using the NK activating receptor, NKp46, which recognizes the Epa adhesins., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

Unlabelled: Cryptococcus neoformans is a pathogenic yeast and a leading cause of life-threatening meningitis in AIDS patients. Natural killer (NK) cells are important immune effector cells that directly recognize and kill C. neoformans via a perforin-dependent cytotoxic mechanism. We previously showed that NK cells from HIV-infected patients have aberrant anticryptococcal killing and that interleukin-12 (IL-12) restores the activity at least partially through restoration of NKp30. However, the mechanisms causing this defect or how IL-12 restores the function was unknown. By examining the sequential steps in NK cell killing of Cryptococcus, we found that NK cells from HIV-infected patients had defective binding of NK cells to C. neoformans Moreover, those NK cells that bound to C. neoformans failed to polarize perforin-containing granules to the microbial synapse compared to healthy controls, suggesting that binding was insufficient to restore a defect in perforin polarization. We also identified lower expression of intracellular perforin and defective perforin release from NK cells of HIV-infected patients in response to C. neoformans Importantly, treatment of NK cells from HIV-infected patients with IL-12 reversed the multiple defects in binding, granule polarization, perforin content, and perforin release and restored anticryptococcal activity. Thus, there are multiple defects in the cytolytic machinery of NK cells from HIV-infected patients, which cumulatively result in defective NK cell anticryptococcal activity, and each of these defects can be reversed with IL-12., Importance: The mechanisms by which NK cells bind directly to pathogens and deploy their deadly cytolytic machinery during microbial host defense are only beginning to be elucidated. With the goal of understanding this process, we used NK cells from HIV-infected patients, which were known to have a defect in killing of Cryptococcus neoformans Taking advantage of previous studies that had shown that IL-12 restored killing, we used the cytokine as a gain-of-function approach to define the relevance of multiple steps in the recognition and cytolytic pathway. We demonstrated that NK cells from HIV-infected patients failed to kill Cryptococcus due to defects in perforin expression, granule polarization, and release of perforin. Additionally, IL-12 restored recognition of C. neoformans through binding of the NK-activating receptor NKp30. These observations identify important mechanisms used by NK cells to kill microbes and determine that defects in NK cells from HIV-infected patients are reversible., (Copyright © 2016 Kyei et al.)

Approximately 1.2 billion people suffer from fungal diseases worldwide. Arguably, the most serious manifestation occurs when pathogenic fungi infect the brain, often causing fatal meningoencephalitis. For most fungi, infection occurs via the vascular route. The organism must first be arrested in the brain microvasculature and transmigrate into the brain parenchyma across the blood-brain barrier. As a result, host immune cells are recruited into the brain to contain the fungi. However, it remains poorly understood how fungi traffic to, and migrate into the brain and how immune cells interact with invading fungi in the brain. A new era of intravital fluorescence microscopy has begun to provide insights. We are able to employ this powerful approach to study dynamic interactions of disseminating fungi with brain endothelial cells as well as resident and recruited immune cells during the brain infection. In this review, with a focus on Cryptococcus neoformans, we will provide an overview of the application of intravital imaging in fungal infections in the brain, discuss recent findings and speculate on possible future research directions.

The activity of Rac in leukocytes is essential for immunity. However, its role in NK cell-mediated anti-microbial signaling remains unclear. In this study, we investigated the role of Rac in NK cell mediated anti-cryptococcal killing. We found thatCryptococcus neoformansindependently activates both Rac and SFK pathways in NK cells, and unlike in tumor killing,Cryptococcusinitiated a novel Rac → PI3K → Erk cytotoxicity cascade. Remarkably, Rac was not required for conjugate formation, despite its essential role in NK cytotoxicity againstC. neoformans Taken together, our data show that, unlike observations with tumor cells, NK cells use a novel Rac cytotoxicity pathway in conjunction with SFK, to killC. neoformans., (© 2016 by The American Society for Biochemistry and Molecular Biology, Inc.)

Cryptococcus gattii is an emerging fungal pathogen on the west coast of Canada and the United States that causes a potentially fatal infection in otherwise healthy individuals. In previous investigations of the mechanisms by which C. gattii might subvert cell-mediated immunity, we found that C. gattii failed to induce dendritic cell (DC) maturation, leading to defective T cell responses. However, the virulence factor and the mechanisms of evasion of DC maturation remain unknown. The cryptococcal polysaccharide capsule is a leading candidate because of its antiphagocytic properties. Consequently, we asked if the capsule of C. gattii was involved in evasion of DC maturation. We constructed an acapsular strain of C. gattii through CAP59 gene deletion by homologous integration. Encapsulated C. gattii failed to induce human monocyte-derived DC maturation and T cell proliferation, whereas the acapsular mutant induced both processes. Surprisingly, encapsulation impaired DC maturation independent of its effect on phagocytosis. Indeed, DC maturation required extracellular receptor signaling that was dependent on TNF-α and p38 MAPK, but not ERK activation, and the cryptococcal capsule blocked this extracellular recognition. Although the capsule impaired phagocytosis that led to pH-dependent serine-, threonine-, and cysteine-sensitive protease-dependent Ag processing, it was insufficient to impair T cell responses. In summary, C. gattii affects two independent processes, leading to DC maturation and Ag processing. The polysaccharide capsule masked extracellular detection and reduced phagocytosis that was required for DC maturation and Ag processing, respectively. However, the T cell response was fully restored by inducing DC maturation., (Copyright © 2016 by The American Association of Immunologists, Inc.)

NK cells play a central role in innate immunity, acting directly through cell-mediated cytotoxicity and by secreting cytokines. TNFα activation of TNFR2 enhances NK cell cytotoxicity, but its effects on the other essential function of NK cells - cytokine production, for which IFNγ is paramount - are poorly defined. We identify the expression of both TNFα receptors on human peripheral blood NK cells (TNFR2 > TNFR1) and show that TNFα significantly augments IFNγ production from IL-2-/IL-12-treated NK cells in vitro, an effect mimicked by a TNFR2 agonistic antibody. TNFα also enhanced murine NK cell IFNγ production via TNFR2 in vitro. In a mouse model characterized by the hepatic recruitment and activation of NK cells, TNFR2 also regulated NK cell IFNγ production in vivo. Specifically, in this model, after activation of an innate immune response, hepatic numbers of TNFR2-expressing and IFNγ-producing NK cells were both significantly increased; however, the frequency of IFNγ-producing hepatic NK cells was significantly reduced in TNFR2-deficient mice. We delineate an important role for TNFα, acting through TNFR2, in augmenting cytokine-induced NK cell IFNγ production in vivo and in vitro, an effect with significant potential implications for the regulation of innate and adaptive immune responses., (© 2016 S. Karger AG, Basel.)

CXCR6-GFP(+) cells, which encompass 70% invariant natural killer T cells (iNKT cells), have been found primarily patrolling inside blood vessels in the liver. Although the iNKT cells fail to interact with live pathogens, they do respond to bacterial glycolipids presented by CD1d on liver macrophage that have caught the microbe. In contrast, in this study using dual laser multichannel spinning-disk intravital microscopy of joints, the CXCR6-GFP, which also made up 60-70% iNKT cells, were not found in the vasculature but rather closely apposed to and surrounding the outside of blood vessels, and to a lesser extent throughout the extravascular space. These iNKT cells also differed in behavior, responding rapidly and directly to joint-homing pathogens like Borrelia burgdorferi, which causes Lyme disease. These iNKT cells interacted with B. burgdorferi at the vessel wall and disrupted dissemination attempts by these microbes into joints. Successful penetrance of B. burgdorferi out of the vasculature and into the joint tissue was met by a lethal attack by extravascular iNKT cells through a granzyme-dependent pathway, an observation also made in vitro for iNKT cells from joint but not liver or spleen. These results suggest a novel, critical extravascular iNKT cell immune surveillance in joints that functions as a cytotoxic barrier and explains a large increase in pathogen burden of B. burgdorferi in the joint of iNKT cell-deficient mice, and perhaps the greater susceptibility of humans to this pathogen because of fewer iNKT cells in human joints.

Transmissible strains of Pseudomonas aeruginosa have been described for cystic fibrosis (CF) and may be associated with a worse prognosis. Using a comprehensive strain biobank spanning 3 decades, we sought to determine the prevalence and stability of chronic P. aeruginosa infection in an adult population. P. aeruginosa isolates from sputum samples collected at initial enrollment in our adult clinic and at the most recent clinic visit were examined by a combination of pulsed-field gel electrophoresis and multilocus sequence typing and compared against a collection of established transmissible and local non-CF bronchiectasis (nCFB) isolates. A total of 372 isolates from 107 patients, spanning 674 patient-years, including 66 patients with matched isolates from initial and final encounters, were screened. A novel clone with increased antibacterial resistance, termed the prairie epidemic strain (PES), was found in 29% (31/107 patients) of chronically infected patients referred from multiple prairie-based CF centers. This isolate was not found in those diagnosed with CF as adults or in a control population with nCFB. While 90% (60/66 patients) of patients had stable infection over a mean of 10.8 years, five patients experienced strain displacement of unique isolates, with PES occurring within 2 years of transitioning to adult care. PES has been present in our cohort since at least 1987, is unique to CF, generally establishes chronic infection during childhood, and has been found in patients at the time of transition of patients from multiple prairie-based CF clinics, suggesting broad endemicity. Studies are under way to evaluate the clinical implications of PES infection.

Natural killer (NK) cells are a subset of immune effectors that directly bind and kill fungi via a perforin-dependent mechanism. The receptor mediating this activity and its potential role in disease remain unknown. Using an unbiased approach, we determined that NKp30 is responsible for recognition and killing of the fungal pathogens Cryptococcus and Candida. NKp30 was required for NK cell-fungal conjugate formation, phosphatidylinositol 3-kinase (PI3K) signaling, and perforin release. Because fungal infections are a leading cause of death in AIDS patients, we examined NKp30 expression in HIV-infected patients. NK cells from these patients had diminished NKp30 expression, defective perforin release, and blunted microbicidal activity. Surprisingly, interleukin-12 (IL-12) restored NKp30 expression and fungal killing. Thus, the NKp30 receptor plays a critical role in NK cell antifungal cytotoxicity, and diminished expression of NKp30 is responsible for defective antifungal activity of NK cells from HIV-infected patients, which can be corrected with IL-12., (Copyright © 2013 Elsevier Inc. All rights reserved.)

Natural killer (NK) cells directly recognize and kill fungi, such as the pathogenic fungus Cryptococcus neoformans, via cytolytic mechanisms. However, the precise signaling pathways governing this NK cell microbicidal activity and the implications for fungal recognition are still unknown. Previously, it was reported that NK cell anticryptococcal activity is mediated through a conserved phosphatidylinositol 3-kinase-extracellular signal-regulated kinase 1/2 (PI3K-ERK1/2) pathway. Using YT (a human NK-like cell line) and primary human NK cells, we sought to identify the upstream, receptor-proximal signaling elements that led to fungal cytolysis. We demonstrate that Src family kinases were activated in response to C. neoformans. Furthermore, pharmacologic inhibition with an Src kinase inhibitor blocked C. neoformans-induced downstream activation of PI3K and ERK1/2 and abrogated cryptococcal killing. At the same time, the inhibitor disrupted the polarization of perforin-containing granules toward the NK cell-cryptococcal synapse but had no effect on conjugate formation between the organism and the NK cell. Finally, small interfering RNA (siRNA) double (but not single) knockdown of two Src family kinases, Fyn and Lyn, blocked cryptococcal killing. Together these data demonstrate a mechanism whereby the Src family kinases, Fyn and Lyn, redundantly mediate anticryptococcal activity through the activation of PI3K and ERK1/2, which in turn facilitates killing by inducing the polarization of perforin-containing granules to the NK cell-cryptococcal synapse.

During adaptive immunity to pathogens, dendritic cells (DCs) capture, kill, process, and present microbial Ags to T cells. Ag presentation is accompanied by DC maturation driven by appropriate costimulatory signals. However, current understanding of the intricate regulation of these processes remains limited. Cryptococcus gattii, an emerging fungal pathogen in the Pacific Northwest of Canada and the United States, fails to stimulate an effective immune response in otherwise healthy hosts leading to morbidity or death. Because immunity to fungal pathogens requires intact cell-mediated immunity initiated by DCs, we asked whether C. gattii causes dysregulation of DC functions. C. gattii was efficiently bound and internalized by human monocyte-derived DCs, trafficked to late phagolysosomes, and killed. Yet, even with this degree of DC activation, the organism evaded pathways leading to DC maturation. Despite the ability to recognize and kill C. gattii, immature DCs failed to mature; there was no increased expression of MHC class II, CD86, CD83, CD80, and CCR7, or decrease of CD11c and CD32, which resulted in suboptimal T cell responses. Remarkably, no increase in TNF-α was observed in the presence of C. gattii. However, addition of recombinant TNF-α or stimulation that led to TNF-α production restored DC maturation and restored T cell responses. Thus, despite early killing, C. gattii evades DC maturation, providing a potential explanation for its ability to infect immunocompetent individuals. We have also established that DCs retain the ability to recognize and kill C. gattii without triggering TNF-α, suggesting independent or divergent activation pathways among essential DC functions.

Myxoma virus (MYXV) is a well-established oncolytic agent against different types of tumors. MYXV is also known for its immunomodulatory properties in down-regulating major histocompatibility complex (MHC) I surface expression (via the M153R gene product, a viral E3-ubiquitin ligase) and suppressing T cell killing of infected target cells. MHC I down-regulation, however, favors NK cell activation. Brain tumors including gliomas are characterized by high MHC I expression with impaired NK activity. We thus hypothesized that MYXV infection of glioma cells will promote NK cell-mediated recognition and killing of gliomas. We infected human gliomas with MYXV and evaluated their susceptibility to NK cell-mediated cytotoxicity. MYXV enhanced NK cell-mediated killing of glioma cells (U87 cells, MYXV vs. Mock: 51.73% vs. 28.63%, P = .0001, t test; U251 cells, MYXV vs. Mock: 40.4% vs. 20.03%, P .0007, t test). Using MYXV M153R targeted knockout (designated vMyx-M153KO) to infect gliomas, we demonstrate that M153R was responsible for reduced expression of MHC I on gliomas and enhanced NK cell-mediated antiglioma activity (U87 cells, MYXV vs. vMyx-M153KO: 51.73% vs. 25.17%, P = .0002, t test; U251 cells, MYXV vs. vMyx-M153KO: 40.4% vs. 19.27, P = .0013, t test). Consequently, NK cell-mediated lysis of established human glioma tumors in CB-17 SCID mice was accelerated with improved mouse survival (log-rank P = .0072). These results demonstrate the potential for combining MYXV with NK cells to effectively kill malignant gliomas.

Pulmonary aspergilloma is a chronic fungal infection that has a high mortality when hemoptysis occurs. Surgery is the treatment of choice, but patients often have severe physiologic impairment putting them at risk for significant surgical morbidity and mortality. We present the case of a 63-year-old woman with a large aspergilloma, unfit for surgery due to medical reasons. The aspergilloma was enlarging, with progression of the patient's symptoms of anorexia, cough, chest discomfort, and hemoptysis. Bronchoscopy revealed an airway leading into a cavity with a large fungal ball. Biopsy confirmed Aspergillus fumigatus. Using flexible and rigid bronchoscopy, the aspergilloma was mechanically removed. Eighteen months later the patient reported no hemoptysis, reduced pain and cough, significant weight gain, and improved appetite, with no recurrence of the aspergilloma on repeat imaging. To our knowledge, this is the first reported case of bronchoscopic removal of a large cavitary aspergilloma. This important new treatment modality provides a viable alternative therapy for this potentially life-threatening problem.

Cryptococcus gattii and Cryptococcus neoformans are encapsulated yeasts that can produce a solid tumor-like mass or cryptococcoma. Analogous to malignant tumors, the microenvironment deep within a cryptococcoma is acidic, which presents unique challenges to host defense. Analogous to malignant cells, NK cells kill Cryptococcus. Thus, as in tumor defense, NK cells must kill yeast cells across a gradient from physiologic pH to less than 6 in the center of the cryptococcoma. As acidic pH inhibits anti-tumor activities of NK cells, we sought to determine if there was a similar reduction in the anticryptococcal activity of NK cells. Surprisingly, we found that both primary human NK cells and the human NK cell line, YT, have preserved or even enhanced killing of Cryptococcus in acidic, compared to physiological, pH. Studies to explore the mechanism of enhanced killing revealed that acidic pH does not increase the effector to target ratio, binding of cytolytic cells to Cryptococcus, or the active perforin content in effector cells. By contrast, perforin degranulation was greater at acidic pH, and increased degranulation was preceded by enhanced ERK1/2 phosphorylation, which is essential for killing. Moreover, using a replication defective ras1 knockout strain of Cryptococcus increased degranulation occurred during more rapid replication of the organisms. Finally, NK cells were found intimately associated with C. gattii within the cryptococcoma of a fatal infection. These results suggest that NK cells have amplified signaling, degranulation, and greater killing at low pH and when the organisms are replicating quickly, which would help maintain microbicidal host defense despite an acidic microenvironment.

Recent technical advances have afforded valuable new insights into the pathogenesis of fungal infections in the central nervous system (CNS), which continue to cause devastating complications, particularly in immunocompromised individuals. To cause CNS mycosis, organisms such as Cryptococcus neoformans become blood borne and progress through a series of pathogenic checkpoints that culminate in fungal replication in the brain. Critical steps include fungal arrest in the vasculature of the brain, interaction and signalling of the fungal and endothelial cells leading to transmigration with subsequent parenchymal invasion and fungal replication in the CNS. Previous studies that made use of in vitro and ex vivo approaches contributed greatly to our understanding of brain invasion by fungi. However, the knowledge gained from previous studies relied on in vitro models that did not account for vascular haemodynamics. For this reason, more refined approaches that model blood flow and vascular anatomy are required, andultimately studying fungal invasion and dissemination in vivo. Indeed, in vivo imaging (also known as intravital imaging) has emerged as a valuable technique to probe host-pathogen interactions. In this review, with a focus on C. neoformans, we will provide an overview of the applications of the prior techniques and recent advances, their strengths and limitations in characterizing the migration of fungi into the brain, and unanswered questions that may provide new directions for research., (© 2012 Blackwell Publishing Ltd.)

Background: The study compares the change in best-corrected visual acuity with the change in central retinal sensitivity before treatment and 6 months after treatment with photodynamic therapy in patients with symptomatic central serous chorio retinopathy., Design: Prospective, single-centre, interventional case series., Participants: Eleven consecutive patients with previously untreated central serous chorio retinopathy., Methods: Patients had microperimetry and best-corrected visual acuity recorded before and 6 months after treatment with photodynamic therapy. Refracted best-corrected visual acuity was assessed at 2 m and adjusted to give the number of letters read at 1 m. Threshold microperimetry was performed by presenting a Goldman III stimulus to 29 points over the central 12° around fixation. Significant visual improvement at 6 months was defined as a best-corrected visual acuity ≥10 letters or, microperimetry change in mean retinal sensitivity ≥2 decibels (dB)., Main Outcome Measures: Improvement in best-corrected visual acuity compared with microperimetry following photodynamic therapy treatment in patients with central serous chorio retinopathy., Results: All patients reported a subjective improvement in vision and had complete resolution of subretinal fluid at 6 months. Two patients had a significant improvement in best-corrected visual acuity (mean ± SD +4.2 ± 5.8 letters), compared with all 11 patients who recorded a significant improvement in mean retinal sensitivity (mean ± SD 4.6 ± 1.9 dB) (P < 0.001)., Conclusions: These data suggest that compared with microperimetry, best-corrected visual acuity is underestimating the effectiveness of photodynamic therapy in the treatment of central serous chorio retinopathy., (© 2011 The Authors. Clinical and Experimental Ophthalmology © 2011 Royal Australian and New Zealand College of Ophthalmologists.)

Pulmonary mycoses are among the most feared infections encountered in immunocompromised patients. The problem is amplified by the increasing numbers of chronically immunocompromised patients that have substantially increased both the prevalence and clinical severity of infections caused by fungi. Moreover, fungal infections in this patient population pose challenges in diagnosis and management. Fortunately, recent advances in diagnostics and antifungal therapy, and their direct application to specific diseases, provide important new approaches to this complex and often seriously ill patient population. In this article we review the commonly occurring pulmonary fungal infections in the immunocompromised population with a particular focus on their management.

Malignant gliomas (MGs) are deadly brain tumors with a median survival after resection, radiotherapy and chemotherapy of only 12 months. The natural immunosuppressive state of MG patients and the locally restricted growth of MGs render this neoplasm an excellent target for immunotherapy. Consequently, several failed attempts were made to treat MGs with immune cells. Recent preclinical experimental studies, however, demonstrate that natural killer (NK) cells can kill MGs and therefore hold promise in immunotherapy of MGs. This review describes the experimental and clinical evidence that support the potential of NK cells in therapy of MGs as well as the limitations to NK therapy. Finally, we propose strategies that could circumvent mitigating factors and enhance NK cell therapy for MG patients., (Copyright © 2011 Elsevier Ltd. All rights reserved.)

Recognition of TLR agonists involves a complex interplay among a variety of serum and cell membrane molecules, including mCD14 and sCD14 that is not fully understood. TLR activation results in downstream signaling that induces inflammatory cytokine production in response to pathogenic molecules, such as ExoS, which is a TLR2 and TLR4 agonist produced by the opportunistic pathogen Pseudomonas aeruginosa. We reasoned that responses to ExoS, a protein, might differ from canonical TLR agonists such as LPS. Stimulating the expression of mCD14 with vitamin D3 enhanced the response to ExoS and LPS. Also, blocking anti-CD14 antibody or removing mCD14 using PLC reduced responses to ExoS and LPS. Furthermore, CD14-deficient cells were unable to bind and respond to ExoS, which was restored by stable transfection of mCD14, indicating that mCD14 was required for the response to ExoS. However, addition of sCD14 to culture enhanced responsiveness to LPS but not ExoS. Moreover, the addition of serum did not alter the response to ExoS but enhanced the response to LPS. Despite differences of adaptor molecule use between ExoS and LPS, lipid antagonists that compete for LPS binding to CD14 also inhibited the response to ExoS. These results highlight a fundamental difference between TLR agonists in their requirements for CD14 and serum components. These results suggest that understanding the dissimilarities and targeting overlapping sites of interaction on CD14 may yield a synergistic, clinical benefit during infections where a variety of TLR agonists are present.

With increasing numbers of immune-compromised patients with malignancy, hematologic disease, and HIV, as well as those receiving immunosupressive drug regimens for the management of organ transplantation or autoimmune inflammatory conditions, the incidence of fungal infections has dramatically increased over recent years. Definitive diagnosis of pulmonary fungal infections has also been substantially assisted by the development of newer diagnostic methods and techniques, including the use of antigen detection, polymerase chain reaction, serologies, computed tomography and positron emission tomography scans, bronchoscopy, mediastinoscopy, and video-assisted thorascopic biopsy. At the same time, the introduction of new treatment modalities has significantly broadened options available to physicians who treat these conditions. While traditionally antifungal therapy was limited to the use of amphotericin B, flucytosine, and a handful of clinically available azole agents, current pharmacologic treatment options include potent new azole compounds with extended antifungal activity, lipid forms of amphotericin B, and newer antifungal drugs, including the echinocandins. In view of the changing treatment of pulmonary fungal infections, the American Thoracic Society convened a working group of experts in fungal infections to develop a concise clinical statement of current therapeutic options for those fungal infections of particular relevance to pulmonary and critical care practice. This document focuses on three primary areas of concern: the endemic mycoses, including histoplasmosis, sporotrichosis, blastomycosis, and coccidioidomycosis; fungal infections of special concern for immune-compromised and critically ill patients, including cryptococcosis, aspergillosis, candidiasis, and Pneumocystis pneumonia; and rare and emerging fungal infections.

Previous studies have demonstrated that STAT5 is critical for expression of granulysin and antimicrobial activity. Because the signaling pathway and the resultant microbicidal activity are defective in HIV-infected patients, the mechanism by which STAT5 leads to granulysin expression is of great interest. In the current study, IL-2-stimulated CRL-2105 CD4(+) T cells expressed granulysin and killed Cryptococcus neoformans similar to primary CD4(+) T cells. The enhancer activity of the upstream element of the granulysin promoter was analyzed in primary CD4(+) T cells and CRL-2105 T cells with a luciferase reporter assay, and a STAT5 binding site, 18,302 to 18,177 bp upstream of the transcription start site, was identified as an enhancer. Additionally, the enhancer functioned in the context of heterologous SV40 promoter irrespective of its transcriptional orientation. Chromatin immunoprecipitation and EMSAs demonstrated that the enhancer element bound STAT5 both in vivo and in vitro, and mutation of the STAT5 binding site abrogated its enhancer activity. Furthermore, overexpression of a dominant negative STAT5a abolished the enhancer activity of the STAT5 binding site and abrogated the anticryptococcal activity of IL-2-stimulated primary CD4(+) T cells. Taken together, these data provide details about the complex regulation leading to granulysin expression and anticryptococcal activity in primary CD4(+) T cells.