Effect of IL-17A on the immune response to pulmonary tuberculosis induced by high- and low-virulence strains of Mycobacterium bovis.

Tuberculosis (TB) is an infectious, chronic, and progressive disease occurring globally. Human TB is caused mainly by Mycobacterium tuberculosis (M. tuberculosis), while the main causative agent of bovine TB is Mycobacterium bovis (M. bovis). The latter is one of the most important cattle pathogens and is considered the main cause of zoonotic TB worldwide. The mechanisms responsible for tissue damage (necrosis) during post-primary TB remain elusive. Recently, IL-17A was reported to be important for protection against M. tuberculosis infection, but it is also related to the production of an intense inflammatory response associated with necrosis. We used two M. bovis isolates with different levels of virulence and high IL-17A production to study this important cytokine's contrasting functions in a BALB/c mouse model of pulmonary TB. In the first part of the study, the gene expression kinetics and cellular sources of IL-17A were determined by real time PCR and immunohistochemistry respectively. Non-infected lungs showed low production of IL-17A, particularly by the bronchial epithelium, while lungs infected with the low-virulence 534 strain showed high IL-17A expression on Day 3 post-infection, followed by a decrease in expression in the early stage of the infection and another increase during late infection, on Day 60, when very low bacillary burdens were found. In contrast, infection with the highly virulent strain 04-303 induced a peak of IL-17A expression on Day 14 of infection, 1 week before extensive pulmonary necrosis was seen, being lymphocytes and macrophages the most important sources. In the second part of the study, the contribution of IL-17A to immune protection and pulmonary necrosis was evaluated by suppressing IL-17A via the administration of specific blocking antibodies. Infection with M. bovis strain 534 and treatment with IL-17A neutralizing antibodies did not affect mouse survival but produced a significant increase in bacillary load and a non-significant decrease in inflammatory infiltrate and granuloma area. In contrast, mice infected with the highly virulent 04-303 strain and treated with IL-17A blocking antibodies showed a significant decrease in survival, an increase in bacillary loads on Day 24 post-infection, and significantly more and earlier necrosis. Our results suggest that high expression of IL-17A is more related to protection than necrosis in a mouse model of pulmonary TB induced by M. bovis strains.

Acute lung injury is prevented by monocyte locomotion inhibitory factor in an experimental severe malaria mouse model.

Acute lung injury caused by severe malaria (SM) is triggered by a dysregulated immune response towards the infection with Plasmodium parasites. Postmortem analysis of human lungs shows diffuse alveolar damage (DAD), the presence of CD8 lymphocytes, neutrophils, and increased expression of Intercellular Adhesion Molecule 1 (ICAM-1). P. berghei ANKA (PbA) infection in C57BL/6 mice reproduces many SM features, including acute lung injury characterized by DAD, CD8+ T lymphocytes and neutrophils in the lung parenchyma, and tissular expression of proinflammatory cytokines and adhesion molecules, such as IFNγ, TNFα, ICAM, and VCAM. Since this is related to a dysregulated immune response, immunomodulatory agents are proposed to reduce the complications of SM. The monocyte locomotion inhibitory factor (MLIF) is an immunomodulatory pentapeptide isolated from axenic cultures of Entamoeba hystolitica. Thus, we evaluated if the MLIF intraperitoneal (i.p.) treatment prevented SM-induced acute lung injury. The peptide prevented SM without a parasiticidal effect, indicating that its protective effect was related to modifications in the immune response. Furthermore, peripheral CD8+ leukocytes and neutrophil proportions were higher in infected treated mice. However, the treatment prevented DAD, CD8+ cell infiltration into the pulmonary tissue and downregulated IFNγ. Moreover, VCAM-1 expression was abrogated. These results indicate that the MLIF treatment downregulated adhesion molecule expression, impeding cell migration and proinflammatory cytokine tissular production, preventing acute lung injury induced by SM. Our findings represent a potential novel strategy to avoid this complication in various events where a dysregulated immune response triggers lung injury.

In Vitro Human Endometrial Cells and In Vivo Rat Model Studies Suggest That Ulipristal Acetate Impacts Endometrial Compatibility for Embryo Implantation.

BACKGROUND: Ulipristal acetate (UPA) and levonorgestrel are used as emergency hormonal contraceptives. Although both are highly effective in preventing pregnancy, UPA shows efficacy even when taken up to 120 h after unprotected sexual intercourse. AIMS: To investigate whether the mechanism of UPA's contraceptive action involves post-fertilization effects. METHODS: In vitro and in vivo studies using cultured human endometrial cells and a pre-clinical rat model. RESULTS: Endometrial cells treated with UPA showed changes in the expression of receptivity gene markers and a significant decrease in trophoblast spheroids attached to the cultured cells. In addition, administration of UPA to female unmated rats decreased the expression of implantation-related genes in the endometrium and inhibited the number of implantation sites in the mated group compared to the non-treated group. CONCLUSIONS: These results support that UPA as an emergency contraceptive might have post-fertilization effects that may affect embryo implantation.

Comparison of the transcriptome, lipidome, and c-di-GMP production between BCGΔBCG1419c and BCG, with Mincle- and Myd88-dependent induction of proinflammatory cytokines in murine macrophages.

We have previously reported the transcriptomic and lipidomic profile of the first-generation, hygromycin-resistant (HygR) version of the BCGΔBCG1419c vaccine candidate, under biofilm conditions. We recently constructed and characterized the efficacy, safety, whole genome sequence, and proteomic profile of a second-generation version of BCGΔBCG1419c, a strain lacking the BCG1419c gene and devoid of antibiotic markers. Here, we compared the antibiotic-less BCGΔBCG1419c with BCG. We assessed their colonial and ultrastructural morphology, biofilm, c-di-GMP production in vitro, as well as their transcriptomic and lipidomic profiles, including their capacity to activate macrophages via Mincle and Myd88. Our results show that BCGΔBCG1419c colonial and ultrastructural morphology, c-di-GMP, and biofilm production differed from parental BCG, whereas we found no significant changes in its lipidomic profile either in biofilm or planktonic growth conditions. Transcriptomic profiling suggests changes in BCGΔBCG1419c cell wall and showed reduced transcription of some members of the DosR, MtrA, and ArgR regulons. Finally, induction of TNF-α, IL-6 or G-CSF by bone-marrow derived macrophages infected with either BCGΔBCG1419c or BCG required Mincle and Myd88. Our results confirm that some differences already found to occur in HygR BCGΔBCG1419c compared with BCG are maintained in the antibiotic-less version of this vaccine candidate except changes in production of PDIM. Comparison with previous characterizations conducted by OMICs show that some differences observed in BCGΔBCG1419c compared with BCG are maintained whereas others are dependent on the growth condition employed to culture them.

Negative Regulation of Autophagy during Macrophage Infection by Mycobacterium bovis BCG via Protein Kinase C Activation.

Mycobacterium tuberculosis (Mtb) employs various strategies to manipulate the host's cellular machinery, overriding critical molecular mechanisms such as phagosome-lysosome fusion, which are crucial for its destruction. The Protein Kinase C (PKC) signaling pathways play a key role in regulating phagocytosis. Recent research in Interferon-activated macrophages has unveiled that PKC phosphorylates Coronin-1, leading to a shift from phagocytosis to micropinocytosis, ultimately resulting in Mtb destruction. Therefore, this study aims to identify additional PKC targets that may facilitate Mycobacterium bovis (M. bovis) infection in macrophages. Protein extracts were obtained from THP-1 cells, both unstimulated and mycobacterial-stimulated, in the presence or absence of a general PKC inhibitor. We conducted an enrichment of phosphorylated peptides, followed by their identification through mass spectrometry (LC-MS/MS). Our analysis revealed 736 phosphorylated proteins, among which 153 exhibited alterations in their phosphorylation profiles in response to infection in a PKC-dependent manner. Among these 153 proteins, 55 are involved in various cellular processes, including endocytosis, vesicular traffic, autophagy, and programmed cell death. Importantly, our findings suggest that PKC may negatively regulate autophagy by phosphorylating proteins within the mTORC1 pathway (mTOR2/PKC/Raf-1/Tsc2/Raptor/Sequestosome-1) in response to M. bovis BCG infection, thereby promoting macrophage infection.

Oral exposure to food grade titanium dioxide (E171) induces intestinal and behavioural alterations in adult mice but limited effects in young mice.

BACKGROUND: Food-grade titanium dioxide (E171), a white colourant widely used in ultra-processed food products, has been banned in the European Union. However, its usage is still permitted in medicines, and in several other countries. The estimated intake of E171 in children is higher than in adults, which led us to hypothesise that E171 induces differential effects depending on age, with adult mice being the most susceptible due to age, despite the lower dose. AIM: To evaluate the effects of oral administration of E171 on intestinal permeability, ileum, and colon histology, and how these effects impact anxious and depressive behaviour in young and adult mice of both sexes. METHODS: Young and adult mice of both sexes C57BL/6 mice received 10 mg/kgbw E171/3 times per week for 3 months. E171 was administered orally in water by pipetting, while control groups only received drinking water, then intestinal permeability, histology and animal behaviour were analysed. RESULTS: E171 showed an amorphous shape, primary particles sized below 1 µm and anatase crystalline structure. Oral administration of E171 disrupted the intestinal permeability in adult male and female mice, but no effects were observed in young mice of both sexes. E171 promoted ileal adenoma formation in half of the adult female population, moreover hyperplastic crypts, and hyperplastic goblet cells at histological level in adult mice of both sexes. The colon presented hyperplastic goblet cells, hyperchromatic nuclei, increased proliferation and DNA damage in adult mice of both sexes. The anxiety and depressive behaviour were only altered in adult mice treated with E171, but no changes were detected in young animals of both sexes. CONCLUSIONS: Adult mice displayed higher susceptibility in all parameters analysed in this study compared to young mice of both sexes.

Sulforaphane protects from kidney damage during the release of unilateral ureteral obstruction (RUUO) by activating nuclear factor erythroid 2-related factor 2 (Nrf2): Role of antioxidant, anti-inflammatory, and antiapoptotic mechanisms.

Releasing unilateral ureteral obstruction (RUUO) is the gold standard for decreasing renal damage induced during unilateral ureteral obstruction (UUO); however, the complete recovery after RUUO depends on factors such as the time and severity of obstruction and kidney contralateral compensatory mechanisms. Interestingly, previous studies have shown that kidney damage markers such as oxidative stress, inflammation, and apoptosis are present and even increase after removal obstruction. To date, previous therapeutic strategies have been used to potentiate the recovery of renal function after RUUO; however, the mechanisms involving renal damage reduction are poorly described and sometimes focus on the recovery of renal functionality. Furthermore, using natural antioxidants has not been completely studied in the RUUO model. In this study, we selected sulforaphane (SFN) because it activates the nuclear factor erythroid 2-related factor 2 (Nrf2), a transcription factor that induces an antioxidant response, decreasing oxidative stress and inflammation, preventing apoptosis. Thus, we pre-administrated SFN on the second day after UUO until day five, where we released the obstruction on the three days after UUO. Then, we assessed oxidative stress, inflammation, and apoptosis markers. Interestingly, we found that SFN administration in the RUUO model activated Nrf2, inducing its translocation to the nucleus to activate its target proteins. Thus, the Nrf2 activation upregulated glutathione (GSH) content and the antioxidant enzymes catalase, glutathione peroxidase (GPx), and glutathione reductase (GR), which reduced the oxidative stress markers. Moreover, the improvement of antioxidant response by SFN restored S-glutathionylation in the mitochondrial fraction. Activated Nrf2 also reduced inflammation by lessening the nucleotide-binding domain-like receptor family pyrin domain containing 3 and interleukin 1ß (IL-1ß) production. Reducing oxidative stress and inflammation prevented apoptosis by avoiding caspase 3 cleavage and increasing B-cell lymphoma 2 (Bcl2) levels. Taken together, the obtained results in our study showed that the upregulation of Nrf2 by SFN decreases oxidative stress, preventing inflammation and apoptosis cell death during the release of UUO.

Adenoviral Vector Codifying for TNF as a Co-Adjuvant Therapy against Multi-Drug-Resistant Tuberculosis.

Mycobacterium tuberculosis is the main causal agent of pulmonary tuberculosis (TB); the treatment of this disease is long and involves a mix of at least four different antibiotics that frequently lead to abandonment, favoring the surge of drug-resistant mycobacteria (MDR-TB), whose treatment becomes more aggressive, being longer and more toxic. Thus, the search for novel strategies for treatment that improves time or efficiency is of relevance. In this work, we used a murine model of pulmonary TB produced by the MDR-TB strain to test the efficiency of gene therapy with adenoviral vectors codifying TNF (AdTNF), a pro-inflammatory cytokine that has protective functions in TB by inducing apoptosis, granuloma formation and expression of other Th1-like cytokines. When compared to the control group that received an adenoviral vector that codifies for the green fluorescent protein (AdGFP), a single dose of AdTNF at the chronic active stage of the disease produced total survival, decreasing bacterial load and tissue damage (pneumonia), which correlated with an increase in cells expressing IFN-γ, iNOS and TNF in pneumonic areas and larger granulomas that efficiently contain and eliminate mycobacteria. Second-line antibiotic treatment against MDR-TB plus AdTNF gene therapy reduced bacterial load faster within a week of treatment compared to empty vector plus antibiotics or antibiotics alone, suggesting that AdTNF is a new potential type of treatment against MDR-TB that can shorten second-line chemotherapy but which requires further experimentation in other animal models (non-human primates) that develop a more similar disease to human pulmonary TB.

Effects of Mycobacterium vaccae NCTC 11659 and Lipopolysaccharide Challenge on Polarization of Murine BV-2 Microglial Cells.

Previous studies have shown that the in vivo administration of soil-derived bacteria with anti-inflammatory and immunoregulatory properties, such as Mycobacterium vaccae NCTC 11659, can prevent a stress-induced shift toward an inflammatory M1 microglial immunophenotype and microglial priming in the central nervous system (CNS). It remains unclear whether M. vaccae NCTC 11659 can act directly on microglia to mediate these effects. This study was designed to determine the effects of M. vaccae NCTC 11659 on the polarization of naïve BV-2 cells, a murine microglial cell line, and BV-2 cells subsequently challenged with lipopolysaccharide (LPS). Briefly, murine BV-2 cells were exposed to 100 µg/mL whole-cell, heat-killed M. vaccae NCTC 11659 or sterile borate-buffered saline (BBS) vehicle, followed, 24 h later, by exposure to 0.250 µg/mL LPS (Escherichia coli 0111: B4; n = 3) in cell culture media vehicle (CMV) or a CMV control condition. Twenty-four hours after the LPS or CMV challenge, cells were harvested to isolate total RNA. An analysis using the NanoString platform revealed that, by itself, M. vaccae NCTC 11659 had an "adjuvant-like" effect, while exposure to LPS increased the expression of mRNAs encoding proinflammatory cytokines, chemokine ligands, the C3 component of complement, and components of inflammasome signaling such as Nlrp3. Among LPS-challenged cells, M. vaccae NCTC 11659 had limited effects on differential gene expression using a threshold of 1.5-fold change. A subset of genes was assessed using real-time reverse transcription polymerase chain reaction (real-time RT-PCR), including Arg1, Ccl2, Il1b, Il6, Nlrp3, and Tnf. Based on the analysis using real-time RT-PCR, M. vaccae NCTC 11659 by itself again induced "adjuvant-like" effects, increasing the expression of Il1b, Il6, and Tnf while decreasing the expression of Arg1. LPS by itself increased the expression of Ccl2, Il1b, Il6, Nlrp3, and Tnf while decreasing the expression of Arg1. Among LPS-challenged cells, M. vaccae NCTC 11659 enhanced LPS-induced increases in the expression of Nlrp3 and Tnf, consistent with microglial priming. In contrast, among LPS-challenged cells, although M. vaccae NCTC 11659 did not fully prevent the effects of LPS relative to vehicle-treated control conditions, it increased Arg1 mRNA expression, suggesting that M. vaccae NCTC 11659 induces an atypical microglial phenotype. Thus, M. vaccae NCTC 11659 acutely (within 48 h) induced immune-activating and microglial-priming effects when applied directly to murine BV-2 microglial cells, in contrast to its long-term anti-inflammatory and immunoregulatory effects observed on the CNS when whole-cell, heat-killed preparations of M. vaccae NCTC 11659 were given peripherally in vivo.

Central Nervous System Tuberculosis in a Murine Model: Neurotropic Strains or a New Pathway of Infection?

Tuberculosis (TB) of the central nervous system (CNS) is a lethal and incapacitating disease. Several studies have been performed to understand the mechanism of bacterial arrival to CNS, however, it remains unclear. Although the interaction of the host, the pathogen, and the environment trigger the course of the disease, in TB the characteristics of these factors seem to be more relevant in the genesis of the clinical features of each patient. We previously tested three mycobacterial clinical isolates with distinctive genotypes obtained from the cerebrospinal fluid of patients with meningeal TB and showed that these strains disseminated extensively to the brain after intratracheal inoculation and pulmonary infection in BALB/c mice. In this present study, BALB/c mice were infected through the intranasal route. One of these strains reaches the olfactory bulb at the early stage of the infection and infects the brain before the lungs, but the histological study of the nasal mucosa did not show any alteration. This observation suggests that some mycobacteria strains can arrive directly at the brain, apparently toward the olfactory nerve after infecting the nasal mucosa, and guides us to study in more detail during mycobacteria infection the nasal mucosa, the associated connective tissue, and nervous structures of the cribriform plate, which connect the nasal cavity with the olfactory bulb.

Tuberculosis and lung cancer / Tuberculosis y cáncer de pulmón

Abstract: Objective: To describe the epidemiological studies about the relationship between lung cancer (LC) and pulmonary tuberculosis (Tb) and its possible molecular mechanisms. Materials and methods: We reviewed research databases in search of publications that included keywords LC and Tb. Results: It has been proposed that chronic inflammation in the lungs due to Tb could cause clastogenic activity in the DNA of bronchial epithelium. Another possibility is lateral gene transfer; since Mycobacterium tuberculosis (MTb) is an intracellular organism, bacterial DNA could integrate to bronchial epithelial cells inducing neoplastic transformation. Conclusions: There are epidemiological reports, particularly from Asian countries, which confirm a relationship between LC and Tb. MTb could play an active role in cellular transformation and it is important to elucidate the mechanism involved.

Resumen: Objetivo: Describir los estudios que documentan la relación entre el cáncer de pulmón (CP) y la tuberculosis pulmonar (Tb) y sus posibles mecanismos moleculares. Material y métodos: Se revisaron bases de datos de publicaciones, usando como palabras clave CP y Tb. Resultados: Se ha propuesto que la inflamación crónica en el pulmón provocada por la Tb podría producir actividad clastogénica. Otra posibilidad es la transferencia lateral de genes; Mycobacterium tuberculosis (MTb) es un organismo intracelular facultativo cuyo DNA podría integrarse al material genético del epitelio bronquial induciendo transformación neoplásica. Conclusión: Existen evidencias epidemiológicas, particularmente en países asiáticos, que documentan la relación entre CP y Tb. MTb podría desempeñar un papel activo en la transformación neoplásica cuyo mecanismo debe de ser elucidado.

Variability in the virulence of specific Mycobacterium tuberculosis clinical isolates alters the capacity of human dendritic cells to signal for T cells

BACKGROUND Once in the pulmonary alveoli, Mycobacterium tuberculosis (Mtb) enters into contact with alveolar macrophages and dendritic cells (DCs). DCs represent the link between the innate and adaptive immune system owing to their capacity to be both a sentinel and an orchestrator of the antigen-specific immune responses against Mtb. The effect that the virulence of Mtb has on the interaction between the bacilli and human DCs has not been fully explored. OBJECTIVE To evaluate the effect of Mtb virulence on human monocyte-derived DCs. METHODS We exposed human monocyte-derived DCs to Mtb clinical strains (isolated from an epidemiological Mtb diversity study in Mexico) bearing different degrees of virulence and evaluated the capacity of DCs to internalise the bacilli, control intracellular growth, engage cell death pathways, express markers for activation and antigen presentation, and expand to stimulate autologous CD4+ T cells proliferation. FINDINGS In the case of the hypervirulent Mtb strain (Phenotype 1, strain 9005186, lineage 3), we report that DCs internalise and neutralise intracellular growth of the bacilli, undergo low rates of apoptosis, and contribute poorly to T-cell expansion, as compared to the H37Rv reference strain. In the case of the hypovirulent Mtb strain (Phenotype 4, strain 9985449, lineage 4), although DCs internalise and preclude proliferation of the bacilli, the DCs also display a high level of apoptosis, massive levels of apoptosis that prevent them from maintaining autologous CD4+ T cells in a co-culture system, as compared to H37Rv. MAIN CONCLUSIONS Our findings suggest that variability in virulence among Mtb clinical strains affects the capacity of DCs to respond to pathogenic challenge and mount an immune response against it, highlighting important parallels to studies previously done in mouse models.

Type-2 diabetes alters the basal phenotype of human macrophages and diminishes their capacity to respond, internalise, and control Mycobacterium tuberculosis

BACKGROUND Type 2 diabetes (T2D) is a risk factor for the development of tuberculosis (TB), although the associated mechanisms are not known. OBJECTIVES To study the association between T2D and the basal phenotype of macrophages, and their immune response to Mycobacterium tuberculosis (Mtb) infection. METHODS We evaluated the influence of T2D on the response of monocyte-derived macrophages (MDM) to Mtb in patients with T2D (n = 10) compared to healthy subjects (n = 9), before and after infection with Mtb clinical isolates bearing different degrees of virulence. The levels of cell surface markers for activation secreted cytokines and chemokines, bacterial association, and intracellular bacterial growth were evaluated. FINDINGS The expression levels of HLA-DR, CD80, and CD86 were low while those of of PD-L1 were high in uninfected MDMs derived from patients with diabetes; as a result of Mtb infection, changes were only observed in the expression levels of PD-L1. The levels of cytokines (e.g., IL-6, IL-1β, IL-10, and IL-12) and chemokines (e.g., MCP-1, MIG, and RANTES) are perturbed in MDMs derived from patients with diabetes, both before infection and in response to Mtb infection. In response to the more virulent Mtb strains, the levels of association and bacterial clearance were diminished in MDMs derived from patients with diabetes. CONCLUSIONS T2D affects the basal activation state of the macrophages and its capacity to respond and control Mtb infection.

Producción in vitro de interferón gamma en ratones vacunados con ´Mycobacterium habana´ frente a antígenos de Mycobacterium tuberculosis / In vitro interferon gamma production in mice vaccinated with ´Mycobacterium habana´ against Mycobacterium tuberculosis antigens

Introducción: el desarrollo de nuevas vacunas antituberculosas requiere de la caracterización de la respuesta de inmunidad celular, inducida por el nuevo candidato vacunal frente a los antígenos principales de Mycobacterium tuberculosis. Objetivo: determinar el potencial inmunogénico de ´Mycobacterium habana´ TMC-5135, cuando se usa como vacuna subcutánea en ratones Balb/c. Métodos: en este estudio se inocularon subcutáneamente ratones Balb/c con la cepa viva ´Mycobacterium habana´ TMC-5135 y se determinó la producción in vitro de IFN gamma en cultivos celulares de pulmón, bazo y ganglios inguinales estimulados con antígenos solubles totales y el antígeno 85b. Como grupo control se vacunaron ratones con BCG subcepa Phipps. Resultados: particularmente en los ganglios linfáticos inguinales, ambos antígenos indujeron mayor producción de IFN gamma en los ratones vacunados con ´Mycobacterium habana´que con BCG. Conclusiones: los resultados justifican la realización de nuevas investigaciones usando ´Mycobacterium habana´ TMC-5135 como candidato vacunal para prevenir la tuberculosis.

Introduction: development of new antituberculosis vaccines requires the characterization of the cell-mediated immune responses induced by mycobacterial antigens. Objective: to determine the immunogenic potential of ´Mycobacterium habana´ TMC-5135 when using subcutaneous vaccine in Balb/c mice. Methods: in this study, Balb/c mice were inoculated subcutaneously with live ´Mycobacterium habana´ TMC-5135. The production of IFN gamma in cell suspensions obtained from the lungs, the spleen and the lymph nodes after stimulation with mycobacterial antigens Ag85b or culture filtrate antigens (CFA) was recorded. Results: the production of IFN gamma after stimulation with CFA and Ag85b was higher in mice vaccinated with ´M. habana´ than in animals immunized with BCG. Conclusions: these results encourage new research on ´M. habana´ as vaccinal candidate against tuberculosis.

Producción in vitro de interferón gamma en ratones vacunados con Mycobacterium habana frente a antígenos de Mycobacterium tuberculosis / In vitro interferon gamma production in mice vaccinated with ´Mycobacterium habana´ against Mycobacterium tuberculosis antigens

Introducción: el desarrollo de nuevas vacunas antituberculosas requiere de la caracterización de la respuesta de inmunidad celular, inducida por el nuevo candidato vacunal frente a los antígenos principales de Mycobacterium tuberculosis. Objetivo: determinar el potencial inmunogénico de ´Mycobacterium habana´ TMC-5135, cuando se usa como vacuna subcutánea en ratones Balb/c. Métodos: en este estudio se inocularon subcutáneamente ratones Balb/c con la cepa viva Mycobacterium habana TMC-5135 y se determinó la producción in vitro de IFN gamma en cultivos celulares de pulmón, bazo y ganglios inguinales estimulados con antígenos solubles totales y el antígeno 85b. Como grupo control se vacunaron ratones con BCG subcepa Phipps. Resultados: particularmente en los ganglios linfáticos inguinales, ambos antígenos indujeron mayor producción de IFN gamma en los ratones vacunados con ´Mycobacterium habana´que con BCG. Conclusiones: los resultados justifican la realización de nuevas investigaciones usando ´Mycobacterium habana´ TMC-5135 como candidato vacunal para prevenir la tuberculosis(AU)

Introduction: development of new antituberculosis vaccines requires the characterization of the cell-mediated immune responses induced by mycobacterial antigens. Objective: to determine the immunogenic potential of Mycobacterium habana TMC-5135 when using subcutaneous vaccine in Balb/c mice. Methods: in this study, Balb/c mice were inoculated subcutaneously with live ´Mycobacterium habana´ TMC-5135. The production of IFN gamma in cell suspensions obtained from the lungs, the spleen and the lymph nodes after stimulation with mycobacterial antigens Ag85b or culture filtrate antigens (CFA) was recorded. Results: the production of IFN gamma after stimulation with CFA and Ag85b was higher in mice vaccinated with ´M. habana´ than in animals immunized with BCG. Conclusions: these results encourage new research on ´M. habana´ as vaccinal candidate against tuberculosis(AU)

Acute and subacute toxicity (28 days) of a mixture of ursolic acid and oleanolic acid obtained from Bouvardia ternifolia in mice / Toxicidad aguda y subaguda (28 días) en ratones, de la mezcla de ácido ursólico y ácido oleanólico obtenida de Bouvardia ternifolia

Ursolic acid (UA) and oleanolic acid (OA) are triterpenes that are found in a large number of medicinal plants, one of which is the species Bouvardia ternifolia. These compounds have been shown to have around 120 types of biological activity, especially the hepatoprotective, anti-inflammatory and antimycobacterial effects. Despite having a high therapeutic potential, not much information concerning their toxicity is available. This article describes the results of acute and subacute (28 days) toxicity evaluations in Balb/c mice (both sexes) treated with the mixture of UA/OA obtained from B. ternifolia at doses of 6.5 and 13 mg/kg. The LD50 was >300 mg/kg. During the subacute administration, there was no death of animals and no changes were observed in the growth or weight of the different organs when compared to the control groups. Studies of blood chemistry and blood count showed normal levels in all parameters evaluated. The histopathology of major organs showed no changes or abnormalities. The mixture UA/OA is indeed safe when administered subcutaneously as a single dose of 300 mg/kg or in repeated doses of 13 mg/kg during 28 days.

Los ácidos ursólico (UA) y oleanólico (OA) son triterpenos que se encuentran distribuidos en un gran número de plantas medicinales, una de ellas es la especie Bouvardia ternifolia. Estos compuestos han mostrado alrededor de 120 actividades biológicas, destacando los efectos hepatoprotector, antiinflamatorio y antimicobacteriano. A pesar de ser compuestos con un alto potencial terapéutico, no se han documentado muchos datos acerca de su toxicidad. En este artículo se describen los resultados de la evaluación de toxicidad aguda y subaguda (28 días) en ratones Balb/c de ambos sexos, tratados con la mezcla de AU/AO obtenida de B. ternifolia a dosis de 6.5 y 13 mg/kg. La DL50 fue > 300 mg/kg. Durante la administración subaguda, no hubo muerte de animales, tampoco se observaron alteraciones en su crecimiento ni alteraciones en el peso de los diferentes órganos. Los estudios de biometría hemática y química sanguínea mostraron niveles normales en todos los parámetros evaluados. Los análisis histopatológicos de los principales órganos no presentaron cambios o anormalidades. La mezcla UA/OA es prácticamente inocua cuando se administra subcutáneamente en dosis única de 300 mg/kg y 13 mg/kg en dosis repetida (28 días).

Aspectos biológicos, clínicos y epidemiológicos de la tuberculosis latente: [revision] / Biological, clinical and epidemiological aspects of latent tuberculosis: [review]

Mycobacterium tuberculosis afecta a la humanidad desde hace más de 20 000 años. Su morbimortalidad es elevada, por lo que repercute económicamente en los países en desarrollo. La infección latente, caracterizada por la presencia de bacilos vivos en tejidos del huésped, con ausencia de signos y síntomas clínicos, es una característica de esta enfermedad, ya que la micobacteria puede adaptar su metabolismo para mantenerse viva con baja o nula replicación, dificultando su eliminación de los tejidos por los fármacos antituberculosos y permaneciendo inadvertida al reconocimiento y eliminación por el sistema inmunológico. Varias son las interrogantes de esta forma de tuberculosis (TB): la falta de conocimiento del metabolismo del bacilo en estado durmiente, su relación con la inmunidad del hospedero y la identificación de antígenos como marcadores diagnósticos de infección subclínica durante la latencia. Este artículo resume los aspectos biológicos, clínicos y epidemiológicos más importantes de esta forma de tuberculosis.

Mycobacterium tuberculosis, the causal agent of tuberculosis, has affected humankind for approximately 20 000 years. Tuberculosis is a devastating disease, particularly in developing countries. One of its most notable characteristics is latent infection, in which live bacilli persist in the host tissues without clinical manifestations. Thus, the tuberculous bacilli adapt their metabolism to remain viable with low or no replication, avoiding their elimination by the immune system or conventional chemotherapy. Among the several problems that are particularly important to the understanding of this form of tuberculosis, and are not well-known, are the key metabolic steps that allow mycobacteria to remain in a dormant state and its interaction with host immunity. This article reviews some of the most significant biological, clinical and epidemiological aspects of this form of tuberculosis.

Péptidos antimicrobianos en la inmunidad innata de enfermedades infecciosas / Antimicrobial peptides in the innate immunity of infectious diseases

Los péptidos antimicrobianos son moléculas efectoras clave en la inmunidad innata. Generalmente contienen de 15 a 45 residuos de aminoácidos y en su gran mayoría poseen carga positiva, adem s de que tienen la propiedad de ser anfipáticos. Estos péptidos son secretados por células epiteliales y leucocitos, como es el caso de los macráfagos y neutrófilos. En la actualidad, con base en la traducción de secuencias en programas computacionales se han descrito m s de 800 tipos de péptidos antimicrobianos distribuidos en los reinos animal y vegetal. Estos péptidos pueden ser clasificados de acuerdo con su conformación estructural y la ubicación de sus puentes disulfuro. Las defensinas constituyen uno de los tipos de péptidos antimicrobianos más estudiados, y se dividen en dos familias de acuerdo con la ubicación de sus puentes disulfuro: alfa-defensinas y beta-defensinas. Algunas de estas defensinas pueden ser inducidas por citocinas proinflamatorias, así como por moléculas propias de patógenos, y se ha observado que est n relacionadas con la inmunopatogenia de varias enfermedades. El papel principal de los péptidos antimicrobianos es la lisis directa de microorganismos; sin embargo, a la fecha también se han descrito propiedades quimiotácticas, que le permiten modular el sistema inmune y de esta forma constituir un puente entre la inmunidad innata y la inmunidad adaptativa. Actualmente se han iniciado estudios con la posibilidad de utilizar esta clase de moléculas como nuevos fármacos en diferentes tipos de enfermedades infecciosas.