Ferritin from Mycobacterium abscessus is involved in resistance to antibiotics and oxidative stress.

Mycobacterium abscessus subsp. massiliense (Mycma) is a rapidly growing Mycobacterium belonging to the M. abscessus complex that is often associated with lung and soft tissue infection outbreaks. Mycma is resistant to many antimicrobials, including those used for treating tuberculosis. Therefore, Mycma infections are difficult to treat and may lead to high infectious complication rates. Iron is essential for bacterial growth and establishment of infection. During infection, the host reduces iron concentrations as a defense mechanism. To counteract the host-induced iron deficiency, Mycma produces siderophores to capture iron. Mycma has two ferritins (encoded by mycma_0076 and mycma_0077) modulated by different iron concentrations, which allow the survival of this pathogen during iron scarcity. In this study, we constructed knockout (Mycma 0076KO) and complemented (Mycma 0076KOc) gene strains for mycma_0076 to understand the function of 0076 ferritin. Deletion of mycma_0076 in Mycma led to the transition in colony morphology from smooth to rough, alteration of the glycopeptidolipids spectra, increased permeability of the envelope, reduction in biofilm formation, increased susceptibility to antimicrobials and hydrogen peroxide-induced oxidative stress, and decreased internalization by macrophages. This study shows that Mycma_0076 ferritin in Mycma is involved in resistance to oxidative stress and antimicrobials, and alteration of cell envelope architecture. KEY POINTS: • Deletion of the mycma_0076 gene altered colony morphology to rough; • Mycma 0076KO changed GPL profile; • Absence of Mycma_0076 ferritin results in increased susceptibility to antimicrobials and oxidative stress in Mycma. Legend: a In wild-type M. abscessus subsp. massiliense strain, iron is captured from the environment by carboxymycobactins and mycobactins (1). Iron-dependent regulator (IdeR) proteins bind to ferrous iron (Fe+2) in the bacterial cytoplasm leading to the activation of the IdeR-Fe+2 complex (2). The activated complex binds to the promoter regions of iron-dependent genes, called iron box, which in turn help in the recruitment of RNA polymerase to promote transcription of genes such as mycma_0076 and mycma_0077 ferritin genes (3). Mycma_0076 and Mycma_0077 ferritins bind to excess iron in the medium and promote Fe2+ oxidation into ferric iron (Fe3+) and store iron molecules to be released under iron scarcity conditions. (4) Genes related to biosynthesis and transport of glycopeptidolipids (GPL) are expressed normally and the cell envelope is composed of different GPL species (colored squares represented on the cell surface (GPLs). Consequently, WT Mycma present smooth colony phenotype (5). b In Mycma 0076KO strain, the lack of ferritin 0076 causes overexpression of mycma_0077 (6), but does not restore wild-type iron homeostasis and thus may result in free intracellular iron, even in the presence of miniferritins (MaDps). The excess iron potentiates oxidative stress (7) by generating hydroxyl radicals through Fenton Reaction. During this process, through an unknown mechanism, that could involve Lsr2 (8), the expression of GPL synthesis locus is regulated positively and/or negatively, resulting in alteration of GPL composition in the membrane (as represented by different colors of squares on the cell surface), resulting in a rough colony phenotype (9). The changes of GPL can increase cell wall permeability, contributing to antimicrobial susceptibility (10).

Repurposing miconazole and tamoxifen for the treatment of Mycobacterium abscessus complex infections through in silico chemogenomics approach.

Drug repositioning is an alternative to overcome the complexity of the drug discovery and approval procedures for the treatment of Mycobacterium abscessus Complex (MABSC) infections that are increasing globally due to the emergency of antimicrobial resistance mechanisms. Here, an in silico chemogenomics approach was performed to compare the sequences from 4942 M. abscessus subsp. abscessus (M. abscessus) proteins with 5258 or 3473 therapeutic targets registered in the DrugBank or Therapeutic Target Database, respectively. This comparison identified 446 drugs or drug candidates whose targets were homologous to M. abscessus proteins. These identified drugs were considered potential inhibitors of MABSC (anti-MABSC activity). Further screening and inspection resulted in the selection of ezetimibe, furosemide, itraconazole, miconazole (MCZ), tamoxifen (TAM), and thiabendazole (THI) for experimental validation. Among them, MCZ and TAM showed minimum inhibitory concentrations (MIC) of 32 and 24 µg mL-1 against M. abscessus, respectively. For M. bolletii and M. massiliense strains, MCZ and TAM showed MICs of 16 and 24 µg mL-1, in this order. Subsequently, the antibacterial activity of MCZ was confirmed in vivo, indicating its potential to reduce the bacterial load in the lungs of infected mice. These results show that MCZ and TAM can serve as molecular scaffolds for the prospective hit-2-lead optimization of new analogs with greater potency, selectivity, and permeability.

Dps protein is related to resistance of Mycobacterium abscessus subsp. massiliense against stressful conditions.

Mycobacterium abscessus subsp. massiliense (Mycma) belongs to the Mycobacterium abscessus complex and is a rapidly growing non-tuberculous mycobacterium. The chronic pulmonary, skin, and soft tissue infections that it causes may be difficult to treat due to its intrinsic resistance to the commonly used antimicrobial drugs, making it a serious world public health problem. Iron is an essential nutrient for the growth of microorganisms; nonetheless, it can be toxic when in excess. Thus, bacteria require an iron homeostasis mechanism to succeed in different environments. DNA-binding proteins from starved cells (Dps) are miniferritins with the property to act as additional iron storage proteins but also can bind to DNA, protecting it against hydroxyl radical. Annotation of the Mycma genome revealed the gene mycma_03135 with 79% sequential identity when compared to MSMEG_3242 gene from M. smegmatis mc2 155, which codifies for a known Dps. Recombinant Dps from M. abscessus (rMaDps) was produced in Escherichia coli, purified in soluble form and shown to form high mass oligomers in solution with ferroxidase activity, DNA binding, and protection against damage. The expression of the mycma_03135 gene was induced during Mycma growth in the presence of hydrogen peroxide (H2O2). Additionally, the expression of rMaDps by E. coli conferred greater resistance to H2O2. Thus, this study is the first to identify and characterize a Dps from M. abscessus. KEY POINTS: Mycobacterium abscessus subsp. massiliense express a miniferritin protein (Dps). Mycma Dps binds to DNA and protects against oxidative stress.

The mycma_1113 Gene from Mycobacterium abscessus subsp. massiliense is Related to Siderophore Synthesis.

Iron (Fe) homeostasis control is important for both pathogen and the host. During infection, the host reduces the access of microorganisms to iron, however, studies have shown that virulent pathogens are capable to sequester Fe from host proteins, and establish the infection. M. abscessus subsp. massiliense (Mycma), that is resistant to most drugs used against tuberculosis, was responsible for outbreaks around the world showing increased virulence when compared to other rapidly growing mycobacteria. The goal of this study was to determine whether Mycma produce siderophores and if the mycma_1113 gene expression, a putative homolog of M. tuberculosis mbtB gene located in the mbt gene cluster, is related to the synthesis of these molecules. For that, the effect of different iron concentrations on the growth of Mycma, the expression of mycma_1113 gene, and the production of siderophores was evaluated in vitro and in vivo. It is shown that Mycma produce siderophores under iron deprivation conditions and mycma_1113 gene expression was influenced by iron availability. The mycma_1113 gene expression was also increased after macrophage or in vivo infection indicating that mycobactin synthesis by Mycma could participate in the Fe sequestration from the host during infection. In conclusion, we show that Mycma produces siderophores under iron deprivation conditions and that the mycma_1113 gene is involved in this process, furthermore, this gene expression is induced during infection.

The mc2-CMX vaccine induces an enhanced immune response against Mycobacterium tuberculosis compared to Bacillus Calmette-Guérin but with similar lung inflammatory effects.

Although the attenuated Mycobacterium bovis Bacillus Calmette-Guérin (BCG) vaccine has been used since 1921, tuberculosis (TB) control still proceeds at a slow pace. The main reason is the variable efficacy of BCG protection against TB among adults, which ranges from 0-80%. Subsequently, the mc2-CMX vaccine was developed with promising results. Nonetheless, this recombinant vaccine needs to be compared to the standard BCG vaccine. The objective of this study was to evaluate the immune response induced by mc2-CMX and compare it to the response generated by BCG. BALB/c mice were immunised with both vaccines and challenged with Mycobacterium tuberculosis (Mtb). The immune and inflammatory responses were evaluated by ELISA, flow cytometry, and histopathology. Mice vaccinated with mc2-CMX and challenged with Mtb induced an increase in the IgG1 and IgG2 levels against CMX as well as recalled specific CD4+ T-cells that produced T-helper 1 cytokines in the lungs and spleen compared with BCG vaccinated and challenged mice. Both vaccines reduced the lung inflammatory pathology induced by the Mtb infection. The mc2-CMX vaccine induces a humoral and cellular response that is superior to BCG and is efficiently recalled after challenge with Mtb, although both vaccines induced similar inflammatory reductions.

The endothelin system has a significant role in the pathogenesis and progression of Mycobacterium tuberculosis infection.

Tuberculosis (TB) remains a major global health problem, and although multiple studies have addressed the relationship between Mycobacterium tuberculosis and the host on an immunological level, few studies have addressed the impact of host physiological responses. Proteases produced by bacteria have been associated with important alterations in the host tissues, and a limited number of these enzymes have been characterized in mycobacterial species. M. tuberculosis produces a protease called Zmp1, which appears to be associated with virulence and has a putative action as an endothelin-converting enzyme. Endothelins are a family of vasoactive peptides, of which 3 distinct isoforms exist, and endothelin 1 (ET-1) is the most abundant and the best-characterized isoform. The aim of this work was to characterize the Zmp1 protease and evaluate its role in pathogenicity. Here, we have shown that M. tuberculosis produces and secretes an enzyme with ET-1 cleavage activity. These data demonstrate a possible role of Zmp1 for mycobacterium-host interactions and highlights its potential as a drug target. Moreover, the results suggest that endothelin pathways have a role in the pathogenesis of M. tuberculosis infections, and ETA or ETB receptor signaling can modulate the host response to the infection. We hypothesize that a balance between Zmp1 control of ET-1 levels and ETA/ETB signaling can allow M. tuberculosis adaptation and survival in the lung tissues.

The use of Mycobacterium tuberculosis HspX and GlcB proteins to identify latent tuberculosis in rheumatoid arthritis patients.

Rheumatoid arthritis (RA) is an autoimmune disease characterised by the destruction of articular cartilage and bone damage. The chronic treatment of RA patients causes a higher susceptibility to infectious diseases such as tuberculosis (TB); one-third of the world's population is latently infected (LTBI) with Mycobacterium tuberculosis (Mtb). The tuberculin skin test is used to identify individuals LTBI, but many studies have shown that this test is not suitable for RA patients. The goal of this work was to test the specific cellular immune responses to the Mtb malate synthase (GlcB) and heat shock protein X (HspX) antigens of RA patients and to correlate those responses with LTBI status. The T-helper (Th)1, Th17 and Treg-specific immune responses to the GlcB and HspX Mtb antigens were analysed in RA patients candidates for tumour necrosis factor-α blocker treatment. Our results demonstrated that LTBI RA patients had Th1-specific immune responses to GlcB and HspX. Patients were followed up over two years and 14.3% developed active TB. After the development of active TB, RA patients had increased numbers of Th17 and Treg cells, similar to TB patients. These results demonstrate that a GlcB and HspX antigen assay can be used as a diagnostic test to identify LTBI RA patients.

Decreased Expression of CD314 by NK Cells Correlates with Their Ability to Respond by Producing IFN-γ after BCG Moscow Vaccination and Is Associated with Distinct Early Immune Responses.

The immune response to vaccines is complex and results in various outcomes. BCG vaccination induces innate and specific responses that can lead to protection against tuberculosis, and cross-protection against other infections. NK cells have been associated with BCG-induced protection. Therefore, we hypothesize that differences in NK cell status before BCG vaccination may have a role in the ability of BCG to activate the immune response. Participants of a clinical trial were evaluated after BCG vaccination. The participants were assigned to different groups according to variation in IFN-γ expression by NK cells between days 1 and 15 after BCG vaccination. Individuals that presented a higher increase in IFN-γ expression by NK cells presented reduced CD314 expression at day 1, and after vaccination an increase in inflammatory NK cells and CD4 T-cell expression of IL-17. A negative correlation between expression of CD314 at day 1 and that of IFN-γ by NK cells after BCG vaccination was observed. Participants with lower of IFN-γ expression by NK cells after BCG vaccination presented an increase in the cytotoxic NK subpopulation and CD4 T-cell expression of IL-17 and IFN-γ. In conclusion, the expression of CD314 by NK cells before BCG vaccination influences their IFN-γ responses, generation of NK subpopulations, and the specific T immune response at 15 days after vaccination.

Complete genome sequence of Mycobacterium massiliense.

Mycobacterium massiliense is a rapidly growing bacterium associated with opportunistic infections. The genome of a representative isolate (strain GO 06) recovered from wound samples from patients who underwent arthroscopic or laparoscopic surgery was sequenced. To the best of our knowledge, this is the first announcement of the complete genome sequence of an M. massiliense strain.

Mycobacterium bovis PknG R242P Mutation Results in Structural Changes with Enhanced Virulence in the Mouse Model of Infection.

Mycobacterium bovis is the causative agent of tuberculosis in domestic and wild animal species and sometimes in humans, presenting variable degrees of pathogenicity. It is known that PknG is involved in the first steps of Mycobacterium tuberculosis macrophage infection and immune evasion. We questioned whether M. bovispknG genes were conserved among mycobacteria and if natural genetic modifications would affect its virulence. We discovered a single mutation at a catalytic domain (R242P) of one M. bovis isolate and established the relation between the presence of R242P mutation and enhanced M. bovis virulence. Here, we demonstrated that R242P mutation alters the PknG protein conformation to a more open ATP binding site cleft. It was observed that M. bovis with PknG mutation resulted in increased growth under stress conditions. In addition, infected macrophages by M. bovis (R242P) presented a higher bacterial load compared with M. bovis without the pknG mutation. Furthermore, using the mouse model of infection, animals infected with M. bovis (R242P) had a massive innate immune response migration to the lung that culminated with pneumonia, necrosis, and higher mortality. The PknG protein single point mutation in its catalytic domain did not reduce the bacterial fitness but rather increased its virulence.

Positive Effects of Extra-Virgin Olive Oil Supplementation and DietBra on Inflammation and Glycemic Profiles in Adults With Type 2 Diabetes and Class II/III Obesity: A Randomized Clinical Trial.

Background: Evidence on the effects of dietary interventions on inflammatory markers in individuals with obesity and type 2 diabetes mellitus (T2DM) is scarce. Our study evaluated the effects of extra-virgin olive oil alone and in combination with a traditional Brazilian diet on inflammatory markers and glycemic profiles in adults with both T2DM and class II/III obesity. Methods: Adults aged 18-64 years with T2DM and class II/III obesity were randomized into two intervention groups: 1) extra-virgin olive oil only and 2) extra-virgin olive oil + a traditional Brazilian diet (OliveOil+DietBra). Data on sociodemographic characteristics, lifestyle, anthropometry, biochemical markers and inflammatory markers were collected. The primary outcomes were glycemic parameters and inflammatory markers. The body mass index (BMI) and weight were the secondary outcomes. Results: Forty individuals with T2DM and class II/III obesity were enrolled, and 34 (85%) completed the intervention course. The intake of olive oil was 37.88 ± 12.50 mL/day in the olive oil group and 37.71 ± 12.23 mL/day in the OliveOil+DietBra group, with no significant difference between groups (p = 0.484). Compared to the olive oil only group, the OliveOil+DietBra group had significantly lower levels of fasting insulin (p = 0.047) at the end of the intervention, whereas the other glycemic parameters were not altered. In the OliveOil+DietBra group, serum levels of inflammatory cytokines, IL-1α (p = 0.006) and adiponectin (p = 0.049) were lower and those of TNFα were higher (p = 0.037). There was a significant reduction in BMI and weight compared to the baseline values in the OliveOil+DietBra group (p = 0.015). Conclusions: The intervention with OliveOil+DietBra effectively decreased the levels of fasting insulin, IL-1α and adiponectin, suggesting its beneficial role in improving the inflammatory profiles and fasting insulin levels in adults with class II/III obesity and T2DM. Clinical Trial Registration: ClinicalTrials.gov, identifier: NCT02463435.

Protease-Based Subunit Vaccine in Mice Boosts BCG Protection against Mycobacterium tuberculosis.

The significant number of people with latent and active tuberculosis infection requires further efforts to develop new vaccines or improve the Bacillus Calmette-Guérin (BCG), which is the only approved vaccine against this disease. In this study, we developed a recombinant fusion protein (PEPf) containing high-density immunodominant epitope sequences from Rv0125, Rv2467, and Rv2672 Mycobacterium tuberculosis (Mtb) proteases that proved immunogenic and used it to develop a recombinant BCG vaccine expressing the fusion protein. After challenging using Mtb, a specific immune response was recalled, resulting in a reduced lung bacterial load with similar protective capabilities to BCG. Thus BCG PEPf failed to increase the protection conferred by BCG. The PEPf was combined with Advax4 adjuvant and tested as a subunit vaccine using a prime-boost strategy. PEPf + Advax4 significantly improved protection after Mtb challenge, with a reduction in bacterial load in the lungs. Our results confirm that Mtb proteases can be used to develop vaccines against tuberculosis and that the use of the recombinant PEPf subunit protein following a prime-boost regimen is a promising strategy to improve BCG immunity.

Tuberculosis, BCG Vaccination, and COVID-19: Are They Connected?

Evidence from multiple scientific studies suggests that the Bacillus Calmette-Guérin (BCG) vaccine, widely used worldwide as a preventive measure against tuberculosis, also offers crossprotection against other pathogens. This review aimed to gather data from research that studied the mechanisms involved in the immunological protection induced by the BCG vaccine, which may be important in the control of viral infections, such as COVID-19. Through a literature review, we compiled information about the different BCG strains used worldwide, as well as the responses and protection elicited by them. We commented on the mechanisms of immune response to Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), and we discussed the possibility of cross-protection of different BCG strains on the control of COVID-19. Due to the immunomodulatory properties of BCG, some BCG strains were able to induce an effective cellular immune response and, through epigenetic modifications, activate cells of the innate immune system, such as monocytes, macrophages and natural killer cells, which are crucial for the control of viral infections. Although several vaccines have already been developed and used in an attempt to control the COVID-19 pandemic, some BCG vaccine strains may help stimulate the basal defences against these pathogens and can be used as additional defences in this and future pandemics.

Restricted Activation of the NF-κB Pathway in Individuals with Latent Tuberculosis Infection after HIF-1α Blockade.

Tuberculous granuloma formation is mediated by hypoxia-inducible factor 1 alpha (HIF-1α), and is essential for establishing latent tuberculosis infection (LTBI) and its progression to active tuberculosis (TB). Here, we investigated whether HIF-1α expression and adjacent mechanisms were associated with latent or active TB infection. Patients with active TB, individuals with LTBI, and healthy controls were recruited, and the expression of cytokine genes IL15, IL18, TNFA, IL6, HIF1A, and A20 in peripheral blood mononuclear cells (PBMCs) and serum vitamin D (25(OH)D3) levels were evaluated. Additionally, nuclear factor kappa B (NF-κB) and tumor necrosis factor-alpha (TNF-α) levels were analyzed in PBMC lysates and culture supernatants, respectively, after HIF-1α blockade with 2-methoxyestradiol. We observed that IL-15 expression was higher in individuals with LTBI than in patients with active TB, while IL-18 and TNF-α expression was similar between LTBI and TB groups. Additionally, serum 25(OH)D3 levels and expression of IL-6, HIF1A, and A20 were higher in patients with active TB than in individuals with LTBI. Moreover, PBMCs from individuals with LTBI showed decreased NF-κB phosphorylation and increased TNF-α production after HIF-1α blockade. Together, these results suggest that under hypoxic conditions, TNF-α production and NF-κB pathway downregulation are associated with the LTBI phenotype.

Efficacy and Safety of BCG Revaccination With M. bovis BCG Moscow to Prevent COVID-19 Infection in Health Care Workers: A Randomized Phase II Clinical Trial.

The Bacillus Calmette-Guérin (BCG) vaccine, which is widely used to protect children against tuberculosis, can also improve immune response against viral infections. This unicentric, randomized-controlled clinical trial assessed the efficacy and safety of revaccination with BCG Moscow in reducing the positivity and symptoms of COVID-19 in health care workers (HCWs) during the COVID-19 pandemic. HCWs who had negative COVID-19 IgM and IgG and who dedicated at least eight hours per week in facilities that attended to individuals suspected of having COVID-19 were included in the study and were followed for 7, 15, 30, 60, and 180 days by telemedicine. The HCWs were randomly allocated to a revaccinated with BCG group, which received the BCG vaccine, or an unvaccinated group. Revaccination with BCG Moscow was found to be safe, and its efficacy ranged from 30.0% (95.0%CI -78.0 to 72.0%) to 31.0% (95.0%CI -74.0 to 74.0%). Mycobacterium bovis BCG Moscow did not induce NK cell activation at 15-20 days post-revaccination. As hypothesized, revaccination with BCG Moscow was associated with a lower incidence of COVID-19 positivity, though the results did not reach statistical significance. Further studies should be carried out to assess whether revaccination with BCG is able to protect HCWs against COVID-19. The protocol of this clinical trial was registered on August 5th, 2020, at REBEC (Registro Brasileiro de Ensaios Clínicos, RBR-4kjqtg - ensaiosclinicos.gov.br/rg/RBR-4kjqtg/1) and the WHO (# U1111-1256-3892). The clinical trial protocol was approved by the Comissão Nacional de ética de pesquisa- CONEP (CAAE 31783720.0.0000.5078).

Distinct expression of perforin and granzyme B in lip and oral cavity squamous cell carcinoma.

BACKGROUND: Perforin and granzyme B (GB) are the main constituents of cytotoxic T-lymphocyte granules, and they have important roles in preventing the initiation and progression of cancer. METHODS: The aim of this study was to compare the expression of CD8(+) /perforin(+) double-staining and GB(+) cells, by immunohistochemistry, in primary oral cavity squamous cell carcinoma (OCSCC), lip squamous cell carcinoma (LSCC), non-dysplastic leukoplakia (LK), dysplastic LK, actinic cheilitis (AC), oral lichen planus (LP) and normal oral mucosa. RESULTS: Our results showed a higher expression of CD8(+) /perforin(+) and GB(+) cells in LSCC when compared with the samples of OCSCC, non-dysplastic and dysplastic LK, AC, oral LP and normal oral mucosa. In addition, increased CD8(+) /perforin(+) and GB(+) cell numbers were observed in all pre-malignant lesions (non-dysplastic LK, dysplastic LK, AC) when compared with the control. CONCLUSIONS: Perforin and GB proteins may contribute to antitumoural immunity, leading to the direct killing of tumour cells; however, it seems to occur more effectively in LSCC than OCSCC.

Clinical data and molecular analysis of Mycobacterium tuberculosis isolates from drug-resistant tuberculosis patients in Goiás, Brazil.

Drug resistance is one of the major concerns regarding tuberculosis (TB) infection worldwide because it hampers control of the disease. Understanding the underlying mechanisms responsible for drug resistance development is of the highest importance. To investigate clinical data from drug-resistant TB patients at the Tropical Diseases Hospital, Goiás (GO), Brazil and to evaluate the molecular basis of rifampin (R) and isoniazid (H) resistance in Mycobacterium tuberculosis. Drug susceptibility testing was performed on 124 isolates from 100 patients and 24 isolates displayed resistance to R and/or H. Molecular analysis of drug resistance was performed by partial sequencing of the rpoB and katGgenes and analysis of the inhA promoter region. Similarity analysis of isolates was performed by 15 loci mycobacterial interspersed repetitive unit-variable number tandem repeat (MIRU-VNTR) typing. The molecular basis of drug resistance among the 24 isolates from 16 patients was confirmed in 18 isolates. Different susceptibility profiles among the isolates from the same individual were observed in five patients; using MIRU-VNTR, we have shown that those isolates were not genetically identical, with differences in one to three loci within the 15 analysed loci. Drug-resistant TB in GO is caused by M. tuberculosis strains with mutations in previously described sites of known genes and some patients harbour a mixed phenotype infection as a consequence of a single infective event; however, further and broader investigations are needed to support our findings.

Acute immune response to Mycobacterium massiliense in C57BL/6 and BALB/c mice.

Mycobacterium massiliense is an environmental opportunistic pathogen that has been associated with soft tissue infection after minor surgery. We studied the acute immune response of C57BL/6 and BALB/c mice infected intravenously with 10(6) CFU of an M. massiliense strain isolated from a nosocomial infection in Brazil. The results presented here show that M. massiliense is virulent and pathogenic to both C57BL/6 and BALB/c mice, inducing a granulomatous inflammatory reaction that involves the activation of macrophages, dendritic cells, and natural killer cells induced by gamma interferon and interleukin-17 (IL-17) in C57BL/6 mice and by IL-12 in BALB/c mice.

Live Vaccines Have Different NK Cells and Neutrophils Requirements for the Development of a Protective Immune Response Against Tuberculosis.

It has been shown that neutrophils drive NK cells to activate DCs while NK cells regulate neutrophils survival. In response to mycobacteria, NK cells proliferate and produces IFN-γ, that appears to regulate the neutrophilic inflammatory responses to both M. tuberculosis infection and BCG vaccination. Although the role of neutrophils in the immune response to tuberculosis is a matter of debate, neutrophils were shown to be crucial to induce specific response against mc2-CMX vaccine. The objective of this study was to investigate the interplay between NK cells and neutrophils in regard to the development of a protective immune response against M. tuberculosis. Depletion of NK cells during vaccination did not alter the total number of neutrophils or DCs, but reduced the number of activated DCs, thus reducing the generation of Th1 specific immune responses and the protection conferred by mc2-CMX and BCG vaccines. However, only in mc2-CMX vaccination that neutrophil depletion interfered with the NK cell numbers and protection. In conclusion, it was shown that only when both NK and neutrophils were present, specific Th1 response and protection was achieved by mc2-CMX vaccine, while neutrophils although activated upon BCG vaccination were not necessary for the induced protection.

Non-tuberculous mycobacterial lung disease: a brief review focusing on radiological findings.

The incidence and prevalence of lung disease caused by non-tuberculous mycobacteria (NTM-LD) has increased worldwide and its diagnosis represents a complex challenge. This article aims to review the tomographic findings of NTM-LD in order to facilitate their definitive diagnosis. The search for publications on the subject was performed in PMC and Scielo using the keywords 'non-tuberculous mycobacteria', 'lung disease and computed tomography (CT)' and 'radiological findings'. The radiological findings described by 18 articles on mycobacteriosis were reviewed. In addition, CT images of patients diagnosed with NTM-LD were considered to represent radiological findings. Eighteen publications were used whose main findings were pulmonary cavitation (88.9%), bronchiectasis (77.8%), and pulmonary nodules (55.6%). Despite the overlaps in imaging-related analysis of myocobacterioses with other pulmonary infections, such as tuberculosis, the predominant involvement of the middle lobe and lingula should raise suspicion for NTM-LD.