Antigen-specific B cells direct T follicular-like helper cells into lymphoid follicles to mediate Mycobacterium tuberculosis control.

Tuberculosis (TB), caused by Mycobacterium tuberculosis (Mtb), is a global cause of death. Granuloma-associated lymphoid tissue (GrALT) correlates with protection during TB, but the mechanisms of protection are not understood. During TB, the transcription factor IRF4 in T cells but not B cells is required for the generation of the TH1 and TH17 subsets of helper T cells and follicular helper T (TFH)-like cellular responses. A population of IRF4+ T cells coexpress the transcription factor BCL6 during Mtb infection, and deletion of Bcl6 (Bcl6fl/fl) in CD4+ T cells (CD4cre) resulted in reduction of TFH-like cells, impaired localization within GrALT and increased Mtb burden. In contrast, the absence of germinal center B cells, MHC class II expression on B cells, antibody-producing plasma cells or interleukin-10-expressing B cells, did not increase Mtb susceptibility. Indeed, antigen-specific B cells enhance cytokine production and strategically localize TFH-like cells within GrALT via interactions between programmed cell death 1 (PD-1) and its ligand PD-L1 and mediate Mtb control in both mice and macaques.

Publisher Correction: Group 3 innate lymphoid cells mediate early protective immunity against tuberculosis.

An Amendment to this paper has been published and can be accessed via a link at the top of the paper.

Group 3 innate lymphoid cells mediate early protective immunity against tuberculosis.

Tuberculosis is the leading cause of death by an infectious disease worldwide1. However, the involvement of innate lymphoid cells (ILCs) in immune responses to infection with Mycobacterium tuberculosis (Mtb) is unknown. Here we show that circulating subsets of ILCs are depleted from the blood of participants with pulmonary tuberculosis and restored upon treatment. Tuberculosis increased accumulation of ILC subsets in the human lung, coinciding with a robust transcriptional response to infection, including a role in orchestrating the recruitment of immune subsets. Using mouse models, we show that group 3 ILCs (ILC3s) accumulated rapidly in Mtb-infected lungs and coincided with the accumulation of alveolar macrophages. Notably, mice that lacked ILC3s exhibited a reduction in the accumulation of early alveolar macrophages and decreased Mtb control. We show that the C-X-C motif chemokine receptor 5 (CXCR5)-C-X-C motif chemokine ligand 13 (CXCL13) axis is involved in Mtb control, as infection upregulates CXCR5 on circulating ILC3s and increases plasma levels of its ligand, CXCL13, in humans. Moreover, interleukin-23-dependent expansion of ILC3s in mice and production of interleukin-17 and interleukin-22 were found to be critical inducers of lung CXCL13, early innate immunity and the formation of protective lymphoid follicles within granulomas. Thus, we demonstrate an early protective role for ILC3s in immunity to Mtb infection.

NF-κB signaling deficiency in CD11c-expressing phagocytes mediates early inflammatory responses and enhances Mycobacterium tuberculosis control.

Early innate immune responses play an important role in determining the protective outcome of Mycobacterium tuberculosis (Mtb) infection. Nuclear factor kappa B (NF-κB) signaling in immune cells regulates the expression of key downstream effector molecules that mount early anti-mycobacterial responses. Using conditional knockout mice, we studied the effect of abrogation of NF-κB signaling in different myeloid cell types and its impact on Mtb infection. Our results show that absence of IKK2-mediated signaling in all myeloid cells resulted in increased susceptibility to Mtb infection. In contrast, absence of IKK2-mediated signaling specifically in CD11c+ myeloid cells induced early pro-inflammatory cytokine responses, enhanced the recruitment of myeloid cells and mediated early resistance to Mtb. Abrogation of IKK2 in MRP8-expressing neutrophils did not impact either disease pathology or Mtb control. Thus, we describe an early immunoregulatory role for NF-κB signaling in CD11c-expressing phagocytes, and a later protective role for NF-κB in LysM-expressing cells during Mtb infection.

Phospholipase C epsilon-1 (PLCƐ1) mediates macrophage activation and protection against tuberculosis.

Tuberculosis (TB) caused by Mycobacterium tuberculosis (Mtb) infects up to a quarter of the world's population. Although immune responses can control Mtb infection, 5%-10% of infected individuals can progress to active TB disease (progressors). A myriad of host factors regulate disease progression in TB and a better understanding of immune correlates of protection and disease is pivotal for the development of new therapeutics. Comparison of human whole blood transcriptomic metadata with that of macaque TB progressors and Mtb-infected diversity outbred mice (DO) led to the identification of differentially regulated gene (DEG) signatures, associated with TB progression or control. The current study assessed the function of Phospholipase C epsilon (PLCƐ1), the top downregulated gene across species in TB progressors, using a gene-specific knockout mouse model of Mtb infection and in vitro Mtb-infected bone marrow-derived macrophages. PLCƐ1 gene expression was downregulated in TB progressors across species. PLCε1 deficiency in the mouse model resulted in increased susceptibility to Mtb infection, coincident accumulation of lung myeloid cells, and reduced ability to mount antibacterial responses. However, PLCε1 was not required for the activation and accumulation of T cells in mice. Our results suggest an important early role for PLCƐ1 in shaping innate immune response to TB and may represent a putative target for host-directed therapy.

Mycobacterium tuberculosis infection drives differential responses in the bone marrow hematopoietic stem and progenitor cells.

Hematopoietic stem and progenitor cells (HSPCs) play a vital role in the host response to infection through the rapid and robust production of mature immune cells. These HSPC responses can be influenced, directly and indirectly, by pathogens as well. Infection with Mycobacterium tuberculosis (Mtb) can drive lymphopoiesis through modulation of type I interferon (IFN) signaling. We have previously found that the presence of a drug resistance (DR)-conferring mutation in Mtb drives altered host-pathogen interactions and heightened type I IFN production in vitro. But the impacts of this DR mutation on in vivo host responses to Mtb infection, particularly the hematopoietic compartment, remain unexplored. Using a mouse model, we show that, while drug-sensitive Mtb infection induces expansion of HSPC subsets and a skew toward lymphopoiesis, DR Mtb infection fails to induce an expansion of these subsets and an accumulation of mature granulocytes in the bone marrow. Using single-cell RNA sequencing, we show that the HSCs from DR Mtb-infected mice fail to upregulate pathways related to cytokine signaling across all profiled HSC subsets. Collectively, our studies report a novel finding of a chronic infection that fails to induce a potent hematopoietic response that can be further investigated to understand pathogen-host interaction at the level of hematopoiesis.

Response to Hypoxia and the Ensuing Dysregulation of Inflammation Impacts Mycobacterium tuberculosis Pathogenicity.

Rationale: Different Mycobacterium tuberculosis (Mtb) strains exhibit variable degrees of virulence in humans and animal models. Differing stress response strategies used by different strains of Mtb could influence virulence. Objectives: We compared the virulence of two strains of Mtb with use in animal model research: CDC1551 and Erdman. Methods: Rhesus macaques, which develop human-like tuberculosis attributes and pathology, were infected with a high dose of either strain via aerosol, and virulence was compared by bacterial burden and pathology. Measurements and Main Results: Infection with Erdman resulted in significantly shorter times to euthanasia and higher bacterial burdens and greater systemic inflammation and lung pathology relative to those infected with CDC1551. Macaques infected with Erdman also exhibited significantly higher early inflammatory myeloid cell influx to the lung, greater macrophage and T cell activity, and higher expression of lung remodeling (extracellular matrix) genes, consistent with greater pathology. Expression of NOTCH4 (neurogenic locus notch homolog 4) signaling, which is induced in response to hypoxia and promotes undifferentiated cellular state, was also higher in Erdman-infected lungs. The granulomas generated by Erdman, and not CDC1551, infection appeared to have larger regions of necrosis, which is strongly associated with hypoxia. To better understand the mechanisms of differential hypoxia induction by these strains, we subjected both to hypoxia in vitro. Erdman induced higher concentrations of DosR regulon relative to CDC1551. The DosR regulon is the global regulator of response to hypoxia in Mtb and critical for its persistence in granulomas. Conclusions: Our results show that the response to hypoxia is a critical mediator of virulence determination in Mtb, with potential impacts on bacillary persistence, reactivation, and efficiency of therapeutics.

Availability of Operative Surgical Experience and Supervision for Competency-Based Education: A Review of A General Surgery Program at A Tertiary Care Teaching Hospital in Pakistan.

BACKGROUND: In view of importance for competency-based education (CBE), we undertook a self-study to elicit the available operative surgical workload and supervision for residents in the general surgical residency program at the teaching hospital in Karachi. METHODOLOGY: This was a cross-sectional study spanning a 5-year period between January 2015 and December 2019. The numbers of surgical residents during this period were identified. Five procedures were selected as core general surgical procedures: incision and drainage of superficial abscess, laparoscopic appendectomy, laparoscopic cholecystectomy, open inguinal hernia repair, and perianal procedures. Trends of the number of residents per year and the numbers of procedures per year were determined. The mean number of core procedures per eligible resident during their entire training was calculated to represent potential operative surgical experience and were benchmarked. The ratio of the average number of residents rotating in general surgery per year to the number of attending surgeons was determined as a measure of available supervision. RESULT: The mean total number of general surgical residents per year was 31.2 (range 28-35). The numbers of core general surgical procedures were consistent over the years of study. Potential exposure of eligible residents to each core procedure during their entire training was: 19.5 cases for incision and drainage of superficial abscess; 89 cases for laparoscopic appendectomy; 113.6 for inguinal hernia repair, 267.5 for laparoscopic cholecystectomy and 64.5 for perianal procedures. The average yearly residents to full-time attending surgeons' ratio was 2.5. The workload of core general surgical procedures at AKUH was higher than the Accreditation Council for Graduate Medical Education (ACGME) recommended volumes for operative surgical experience for residents in the US. CONCLUSION: This method of assessing the potential of a surgical program for transitioning to CBE appears practical and can be generalized.

Comparative Study of Antimicrobial Activity of Silver, Gold, and Silver/Gold Bimetallic Nanoparticles Synthesized by Green Approach.

Nanotechnology is one of the most recent technologies. It is uncertain whether the production of small-size nanoparticles (NPs) can be achieved through a simple, straightforward, and medicinally active phytochemical route. The present study aimed to develop an easy and justifiable method for the synthesis of Ag, Au, and their Ag/Au bimetallic NPs (BNPs) by using Hippeastrum hybridum (HH) extract, and then to investigate the effects of Ag, Au, and their Ag/Au BNPs as antimicrobial and phytotoxic agents. Ag, Au, and their Ag/Au BNPs were characterized by UV-visible spectroscopy, FT-IR spectroscopy, XRD, EDX, and SEM analysis. XRD analysis conferring to the face of face-centered cubic crystal structure with an average size of 13.3, 10.72, and 8.34 nm of Ag, Au, and Ag/Au BNPs, respectively. SEM showed that Ag, Au, and Ag/Au BNPs had spherical morphologies, with calculated nano measurements of 40, 30, and 20 nm, respectively. The EDX analysis confirmed the composition of elemental Ag signal of the HH-AgNPs with 22.75%, Au signal of the HH-AuNPs with 48.08%, Ag signal with 12%, and Au signal with 38.26% of the Ag/Au BNPs. The Ag/Au BNPs showed an excellent antimicrobial efficacy against Gram-positive Staphylococcus aureus, Actinomycetes meriye, Bacillus cereus, Streptococcus pyogenes, Methicillin-resistant Staphylococcus aureus, Micrococcus luteus, Streptococcus pneumonia, and Gram-negative Klebsiella pneumonia, Escherichia coli, and Serratia marcescens bacterial strains, as well as against three fungal strains (Aspergillus niger, Aspergillus fumigatus, and Aspergillus flavus) compared to HH extract, HH-AgNPs, and HH-AuNPs. However, further investigations are recommended to be able to minimize potential risks of application.

Pre-procedural SARS-CoV-2 PCR testing in the pulmonary function laboratory at a tertiary government hospital in Qatar: A clinical audit.

BACKGROUND: Prior to pulmonary function testing (PFT), local and international recommendations advise pre-procedural screening. Pulmonary function tests generate aerosol droplets containing millions of viruses, significantly increasing the risk of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) transmission not only to the individuals in and around the PFT office, but also to subsequent patients who undergo the test later in the same room. METHODS: This clinical audit was carried out to establish the rate of positive pre-procedural SARS-CoV-2 PCR testing before a PFT. The data were obtained over a 6-week period from our ATS accredited pulmonary function laboratory at the Hamad General Hospital, Qatar (December 01, 2021, to January 10, 2022). The PFT laboratory was closed from January 10, 2022, till the date of this report (January 27, 2022) owing to an increase in COVID cases in the community in Qatar during the fourth wave. RESULTS: All the patients scheduled for PFT were asymptomatic of COVID-19. A total of 331 individuals were scheduled for PFT, and 221 PFTs were performed. There were 109 no-shows for both the PCR and the PFT. Between weeks 1 and 4, all the pre-procedural SARS-CoV-2 PCR tests were negative. The weekly average number of COVID-19 cases in Qatar increased from 157 per 100,000 population in week 1 to 2,918 in week 6.2 There was a similar trend in the pre-procedural SARS-CoV-2 PCR tests that increased and resulted in identifying 9 cases with positive SARS-CoV-2 PCR test over weeks 5 and 6 (Figure 1). CONCLUSION: As the number of documented positive SARS-CoV-2 PCR tests in the community grew, so did the pre-procedural COVID-19 PCR positivity and the number of no-shows. The large number of no-shows may indicate greater worry or concern about contracting COVID-19 when visiting the hospital amid peak community cases. Our findings further call into question the utility of routinely performing pre-procedural PCR screening in asymptomatic cases when the prevalence of COVID-19 is low in the local population. Perhaps, it is time to consider replacing this with on-the-spot quick antigen testing for more effective use of resources.

Ornithine carbamoyltransferase from psychrophiles to thermophiles: structural evolution of catalytic fold to accommodate physiological diversity.

Here, we have analyzed the enzyme ornithine carbamoyltransferase (OCTase) in different classes of microorganisms belonging to psychrophiles, mesophiles and thermophiles. This OCTase catalyzes the formation of citrulline from carbamoyl phosphate (CP) and ornithine (ORN) in arginine biosynthesis pathway and has certain unique adaptations to regulate metabolic pathways in extreme conditions. The tertiary structure of OCTase showed two binding domains, the CP domain and ORN-binding domain at N and C terminals, respectively. We propose general acid-base catalysis in Pseudomonas gessardii between His259 and Asp220 in which later may act as a recipient of proton in the process. The comparative docking analysis showed that substrate-binding loops have been evolved to accommodate their lifestyles across the physiological temperature range where two substrates bind on two distinct loops in psychrophiles and mesophiles, whereas both the substrates bind on a single-substrate-binding loop in thermophiles and bring down the flexibility of the active site pocket to improve its evolutionary fitness.

Decision making on antenatal screening results: A comparative Q-method study of women from two Chinese cities.

BACKGROUND: Although an integral part of ethical and quality health care, little is known about the informed decision making of Chinese women with different socioeconomic backgrounds within the context of antenatal testing. METHODS: To explore women's viewpoints on informed decision making regarding antenatal screening, a Q-methodology study that combines both quantitative factor analysis and interviews was conducted between June 2016 and February 2017 in Shanghai and Duyun. A total of 169 women (84 Shanghai and 85 Duyun) participated in the study of 41 ranked statements along a Q-sorting grid. RESULTS: Using by-person factor analysis, five distinct viewpoints are identified: (a) choice is shared with the partner/husband, but the mother has the right to make the final decision; (b) having antenatal tests is not about choice but about a mother's responsibility; (c) choice is a shared decision led primarily by the partner/husband and secondarily by the doctors; (d) choice should be made using the advice of doctors, but the decision should be made with the partner/husband; and (e) choice is a responsibility shared with the partner, family and doctors. CONCLUSIONS: The study reveals that women with better education and higher incomes demonstrate more autonomy than those with less education. The nuclear family clearly emerges as the main decision makers in health-care services in China. PATIENT AND PUBLIC CONTRIBUTION: The 169 participants shared their views and stories for at least an hour. They were debriefed after the interviews and contributed their thoughts on our study design and interpretation of the data.

Mycobacterium tuberculosis HN878 Infection Induces Human-Like B-Cell Follicles in Mice.

Specific spatial organization of granulomas within the lungs is crucial for protective anti-tuberculosis (TB) immune responses. However, only large animal models such as macaques are thought to reproduce the morphological hallmarks of human TB granulomas. In this study, we show that infection of mice with clinical "hypervirulent" Mycobacterium tuberculosis (Mtb) HN878 induces human-like granulomas composed of bacilli-loaded macrophages surrounded by lymphocytes and organized localization of germinal centers and B-cell follicles. Infection with laboratory-adapted Mtb H37Rv resulted in granulomas that are characterized by unorganized clusters of macrophages scattered between lymphocytes. An in-depth exploration of the functions of B cells within these follicles suggested diverse roles and the activation of signaling pathways associated with antigen presentation and immune cell recruitment. These findings support the use of clinical Mtb HN878 strain for infection in mice as an appropriate model to study immune parameters associated with human TB granulomas.

Interplay between two spin states determines the hydroxylation catalyzed by P450 monooxygenase from Trichoderma brevicompactum.

Tri11 (now renamed as tri22) encoded cytochrome P450 monooxygenase in Trichoderma brevicompactum catalyzes the C-4 C-H hydroxylation of 12, 13-epoxytrichothec-9-ene (EPT) to produce trichodermol in the biosynthetic pathway of trichodermin/harzianum A. The density functional theory (DFT)-quantum mechanics (QM) approach is applied to elucidate the hydroxylation of EPT by using a model active species of P450 (Cpd I). The QM calculations were performed on the active site complex, to find out transition-state structure, intermediate, and product complexes for the two spin states at different potential energy surfaces. The two state reactivity rebound-free product formation resulted from the interplay of two spin states (doublet and quartet).

Fungal P450 monooxygenases - the diversity in catalysis and their promising roles in biocontrol activity.

The fungal P450s catalyze vital monooxygenation reactions in primary and secondary metabolism, which may lead to the production of diverse secondary metabolites. Many of these, such as from the family of trichothecenes, involve in biocontrol activities. The diversified nature of fungal P450 monooxygenases makes their host organisms adoptable to various ecological niches. The available genome data analysis provided an insight into the activity and mechanisms of the fungal P450s. However, still more structural and functional studies are needed to elucidate the details of its catalytic mechanism, and the advance studies are also required to decipher further about their dynamic role in various aspects of trichothecene oxygenations. This mini review will provide updated information on different fungal P450 monooxygenases, their genetic diversity, and their role in catalyzing various biochemical reactions leading to the production of plant growth promoting secondary metabolites.

Enhancing inclusion of diverse populations in genomics: A competence framework.

Genomic knowledge and technology have developed rapidly over the last decade and increased our capabilities to diagnose and manage rare diseases. However, current genomic datasets lack ethnic diversity as many genomic studies have focused on participants of white European ancestry. Studies, such as the Deciphering Developmental Disorders study, have been available to participants of any ancestry but have been unsuccessful in recruiting diverse populations. The inclusion of diverse populations in exome and genome sequencing is important to ensure that clinical benefits of genomics advances are equally shared among all populations and to advance scientific knowledge. Our clinical and research experience with the British Pakistani population (the largest ethnic minority in Yorkshire and Humber, accounting for 4.3% of the population) has fostered the development of an innovative cultural competence framework to enhance the inclusion of diverse populations in clinical genomic research and service provision. The application of this framework has the potential to guide healthcare professionals to develop a wide range of competences, so they are ready to embrace genomic advances in order to improve health outcomes for all patients. This practice model will inform precision medicine and improve access of diverse populations to genomic studies. Although based upon work with the Pakistani population in the UK, it is anticipated that the model would be broadly applicable to all underrepresented populations across the world.

Paediatric Bickerstaff brainstem encephalitis: A rare case report.

Bickerstaff Brainstem Encephalitis, a rare variant of Guillain- Barre Syndrome has an estimated prevalence of eight per 100 million individuals. It presents with the classic triad of ataxia, ophthalmoplegia and altered consciousness. We report the case of a 10-year-old child who presented with low grade fever, hypersomnia and inability to walk. Central nervous system examination revealed ophthalmoplegia and multiple cranial nerve palsies. However, CSF examination showed lack of albuminocytological dissociation with no previous history of respiratory or gastrointestinal tract infection. Unavailability of Anti-GQ1b antibodies led to a diagnosis based on suggestive clinical features, abnormal MRI signals and prompt response to corticosteroid administration. Intravenous Methyl Prednisolone in a dose of 30mg/kg/day was administered for 10 days followed by oral Prednisolone 2 mg/kg/day. After complete recovery the patient was discharged, Prednisolone was tapered gradually and eventually discontinued after four months.

A comparative evaluation of serum biochemistry profile and antigenic relatedness among velogenic and mesogenic Avian avulavirus 1 infection in chickens and pigeons.

Newcastle disease (ND), caused by virulent Avian avulavirus 1 (AAvV 1), affects variety of avian species around the globe. Several AAvV 1 viruses of different genotypes have recently emerged with varying clinical impacts on their susceptible hosts. Although experimental infection with velogenic and mesogenic strains in chickens and pigeons is well-studied, nevertheless, there exists a paucity of data for comparative variations in serum biochemistry profile of susceptible hosts upon challenge with isolates of varying pathogenicities. With this background, a comparative assessment of a range of serum biochemical parameters was made following challenge with duck-originated velogenic strain (sub-genotype VIIi; MF437287) and pigeon-originated mesogenic strain (sub-genotype VIm; KU885949) in chickens and pigeons. For each of the isolate, commercial broiler chickens and wild pigeons were challenged (10-6.51 EID50/0.1 mL for sub-genotype VIIi and 10-6.87 EID50/0.1 mL sub-genotype Vim) separately via intranasal and intraocular route. Sera were collected on 0, 3rd, 5th, 7th, and 9th day post-infection (dpi), and processed for quantitative analysis of different biochemical parameters. By day 3 post-infection (pi), a substantial decrease (p < 0.0001) in serum alkaline phosphatase (ALP) was observed in chickens and pigeons challenged with velogenic isolate. On the other hand, from day 5 pi and onward, a significant increase (p < 0.001) in serum ALP and total protein concentration was observed exclusively in pigeons challenged with mesogenic isolate. For serum aspartate aminotransferase (AST), a significant increase (p < 0.05) in concentration was observed on day 3 pi which decreased from day 5 pi and onward in pigeons and chickens challenged with mesogenic isolate. Also, to reveal antigenic differences among homologous and heterologous vaccine and field-prevalent strains, cross-hemagglutination inhibition assay demonstrated antigenically diverse nature (R-value < 0.5) of both strains from vaccine strain (LaSota, genotype II). The study concludes antigenic differences among prevalent genotypes than vaccine strain and, although requires further studies to ascertain study outcomes, the serum biochemical profile may facilitate presumptive diagnosis of disease in their susceptible hosts.

Mutations in the pH-Sensing G-protein-Coupled Receptor GPR68 Cause Amelogenesis Imperfecta.

Amelogenesis is the process of dental enamel formation, leading to the deposition of the hardest tissue in the human body. This process requires the intricate regulation of ion transport and controlled changes to the pH of the developing enamel matrix. The means by which the enamel organ regulates pH during amelogenesis is largely unknown. We identified rare homozygous variants in GPR68 in three families with amelogenesis imperfecta, a genetically and phenotypically heterogeneous group of inherited conditions associated with abnormal enamel formation. Each of these homozygous variants (a large in-frame deletion, a frameshift deletion, and a missense variant) were predicted to result in loss of function. GPR68 encodes a proton-sensing G-protein-coupled receptor with sensitivity in the pH range that occurs in the developing enamel matrix during amelogenesis. Immunohistochemistry of rat mandibles confirmed localization of GPR68 in the enamel organ at all stages of amelogenesis. Our data identify a role for GPR68 as a proton sensor that is required for proper enamel formation.