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Mycobacterium Tuberculosis (mycobacterium + tuberculosis)
Kinds of Mycobacterium Tuberculosis Terms modified by Mycobacterium Tuberculosis Selected AbstractsEtiologic spectrum and pattern of antimicrobial drug susceptibility in bacterial meningitis in Sokoto, NigeriaACTA PAEDIATRICA, Issue 8 2000FE EmeleArticle first published online: 2 JAN 200 Etiologic agents of meningitis were prospectively investigated among patients admitted to Usman Danfodio University Teaching Hospital, Sokoto. Of 1097 cerebrospinal fluid (CSF) samples submitted to the microbiology laboratory from various wards of the hospital, 289 (26%) were microscopically, culturally and/or serologically proven to be bacterial meningitis. The etiologic spectrum was as follows: Neisseria meningitidis (61%), Streptococcus pneumoniae (18%), Haemophilus influenzae (10%), Staphylococcus aureus (6%), Coliform bacilli (3%), Escherichia coli (0.7%), Mycobacterium tuberculosis (0.7%), Listeria monocytogenes (0.4%), Flavobacterium meningosepticum (0.4%) and Pseudomonas putrifasciens (0.4%). Bacterial meningitis was most prevalent (195 or 68%) among children aged 1-9 y, while adults and neonates were least affected. Coliform bacilli caused five of eight neonatal cases. Males were more frequently affected than females (x2=12.50;p < 0.05). Culture and microscopy were comparatively less efficient than the search for bacterial antigens, especially in the diagnosis of Haemophilus meningitis. Antimicrobial susceptibility of N. meningitidis to ampicillin and benzyl penicillin reduced progressively over the years (F = 406.98;p < 0.001). Nineteen (11%) of the isolates (5 Meningococci, 7 Staph. aureus, 1 Haem. influenza and 6 others) showed simultaneous resistance to chloramphenicol, ampicillin and benzyl penicillin. [source] Erythema nodosum and erythema induratum (nodular vasculitis): diagnosis and managementDERMATOLOGIC THERAPY, Issue 4 2010Heidi Gilchrist ABSTRACT Erythema nodosum is the most common type of panniculitis; it may be due to a variety of underlying infectious or otherwise antigenic stimuli. The pathogenesis remains to be elucidated, but both neutrophilic inflammation and granulomatous inflammation are implicated. Beyond treating underlying triggers, therapeutic options consist mainly of nonsteroidal anti-inflammatory drugs, symptomatic care, potassium iodide, and colchicine. Erythema induratum (nodular vasculitis) is a related but distinctly different clinicopathologic reaction pattern of the subcutaneous fat. It is classically caused by an antigenic stimulus from Mycobacterium tuberculosis but may be associated with several other underlying disorders. After appropriate antimicrobial treatment in tuberculous cases, therapy for erythema induratum is similar to options for erythema nodosum. [source] Mycobacterium avium complex infection in a neck abscess: A diagnostic pitfall in fine-needle aspiration biopsy of head and neck lesionsDIAGNOSTIC CYTOPATHOLOGY, Issue 7 2009Valerie A. Fitzhugh M.D. Abstract Fine-needle aspiration biopsy (FNAB) is a useful tool in the diagnosis of mycobacterial disease, especially Mycobacterium tuberculosis. However, nontuberculous mycobacterial infection diagnosed with FNAB material is much rarer, with Mycobacterium avium complex being the most common. In this report, we present the case of a 21-year-old HIV positive man, who presented with a unilateral, tender, enlarging cervical neck mass. FNAB had revealed acute inflammation. Mycobacterium avium complex grew in culture from the material that was aspirated and was confirmed by DNA probe. Because of the paucity of articles on this subject in the cytology literature, it is important to reiterate the value of the material aspirated at the bedside and the clinic in the diagnosis of infectious disease. When faced with antibiotic-resistant cellulitis and abscesses, the FNAB material must be sent for acid fast bacteria smears and culture. Diagn. Cytopathol. 2009. © 2009 Wiley-Liss, Inc. [source] How B cells shape the immune response against Mycobacterium tuberculosisEUROPEAN JOURNAL OF IMMUNOLOGY, Issue 3 2009Paul J. Maglione Abstract Extensive work illustrating the importance of cellular immune mechanisms for protection against Mycobacterium tuberculosis has largely relegated B-cell biology to an afterthought within the tuberculosis (TB) field. However, recent studies have illustrated that B lymphocytes, through a variety of interactions with the cellular immune response, play previously underappreciated roles in shaping host defense against non-viral intracellular pathogens, including M. tuberculosis. Work in our laboratory has recently shown that, by considering these lymphocytes more broadly within their variety of interactions with cellular immunity, B cells have a significant impact on the outcome of airborne challenge with M. tuberculosis as well as the resultant inflammatory response. In this review, we advocate for a revised view of TB immunology in which roles of cellular and humoral immunity are not mutually exclusive. In the context of our current understanding of host defense against non-viral intracellular infections, we review recent data supporting a more significant role of B cells during M. tuberculosis infection than previously thought. [source] Accelerating the secondary immune response by inactivating CD4+CD25+ T regulatory cells prior to BCG vaccination does not enhance protection against tuberculosisEUROPEAN JOURNAL OF IMMUNOLOGY, Issue 3 2008Kylie M. Quinn Abstract CD4+CD25+ natural T regulatory cells (Tregs) have been shown to suppress protective immune responses in several different vaccination models. Since the effect of Tregs on vaccination against tuberculosis (Tb) was unknown, we used a murine model to investigate whether natural Tregs suppress the development of protective immunity following Mycobacterium bovis bacille Calmette-Guérin (BCG) vaccination. Using a monoclonal antibody against CD25, natural Tregs were inactivated prior to vaccination with BCG. The primary immune response was evaluated after BCG vaccination and the secondary immune response was assessed after an intranasal BCG challenge 42,days after vaccination. Inactivation of natural Tregs prior to vaccination led to an increased immune response 14,days after vaccination, increased numbers of antigen-responsive lymphocytes immediately prior to secondary challenge and the earlier appearance of IFN-,-producing CD4+ and CD8+ lymphocytes in the draining lymph nodes and lungs after challenge. Despite this, protection from virulent Mycobacterium tuberculosis or M. bovis aerosol challenge was unaffected by natural Treg inactivation prior to BCG vaccination. This suggests that increasing the primary and accelerating the secondary immune responses by inactivating natural Tregs at the time of vaccination, does not affect the development of protective immunity to Tb. [source] Immunisation with BCG and recombinant MVA85A induces long-lasting, polyfunctional Mycobacterium tuberculosis -specific CD4+ memory T lymphocyte populationsEUROPEAN JOURNAL OF IMMUNOLOGY, Issue 11 2007Natalie Abstract In the search for effective vaccines against intracellular pathogens such as HIV, tuberculosis and malaria, recombinant viral vectors are increasingly being used to boost previously primed T cell responses. Published data have shown prime-boost vaccination with BCG-MVA85A (modified vaccinia virus Ankara expressing antigen 85A) to be highly immunogenic in humans as measured by ex vivo IFN-, ELISPOT. Here, we used polychromatic flow cytometry to investigate the phenotypic and functional profile of these vaccine-induced Mycobacterium tuberculosis (M.tb) antigen 85A-specific responses in greater detail. Promisingly, antigen 85A-specific CD4+ T cells were found to be highly polyfunctional, producing IFN-,, TNF-,, IL-2 and MIP-1,. Surface staining showed the responding CD4+ T cells to be relatively immature (CD45RO+ CD27intCD57,); this observation was supported by the robust proliferative responses observed following antigenic stimulation. Furthermore, these phenotypic and functional properties were independent of clonotypic composition and epitope specificity, which was maintained through the different phases of the vaccine-induced immune response. Overall, these data strongly support the use of MVA85A in humans as a boosting agent to expand polyfunctional M.tb -specific CD4+ T cells capable of significant secondary responses. [source] Studies on structural and functional divergence among seven WhiB proteins of Mycobacterium tuberculosis H37RvFEBS JOURNAL, Issue 1 2009Md. Suhail Alam The whiB -like genes (1-7) of Mycobacterium tuberculosis are involved in cell division, nutrient starvation, pathogenesis, antibiotic resistance and stress sensing. Although the biochemical properties of WhiB1, WhiB3 and WhiB4 are known, there is no information about the other proteins. Here, we elucidate in detail the biochemical and biophysical properties of WhiB2, WhiB5, WhiB6 and WhiB7 of M. tuberculosis and present a comprehensive comparative study on the molecular properties of all WhiB proteins. UV,Vis spectroscopy has suggested the presence of a redox-sensitive [2Fe,2S] cluster in each of the WhiB proteins, which remains stably bound to the proteins in the presence of 8 m urea. The [2Fe,2S] cluster of each protein was oxidation labile but the rate of cluster loss decreased under reducing environments. The [2Fe,2S] cluster of each WhiB protein responded differently to the oxidative effect of air and oxidized glutathione. In all cases, disassembly of the [2Fe,2S] cluster was coupled with the oxidation of cysteine-thiols and the formation of two intramolecular disulfide bonds. Both CD and fluorescence spectroscopy revealed that WhiB proteins are structurally divergent members of the same family. Similar to WhiB1, WhiB3 and WhiB4, apo WhiB5, WhiB6 and WhiB7 also reduced the disulfide of insulin, a model substrate. However, the reduction efficiency varied significantly. Surprisingly, WhiB2 did not reduce the insulin disulfide, even though its basic properties were similar to those of others. The structural and functional divergence among WhiB proteins indicated that each WhiB protein is a distinguished member of the same family and together they may represent a novel redox system for M. tuberculosis. [source] Characterization of Mycobacterium tuberculosis nicotinamidase/pyrazinamidaseFEBS JOURNAL, Issue 4 2008Hua Zhang The nicotinamidase/pyrazinamidase (PncA) of Mycobacterium tuberculosis is involved in the activation of the important front-line antituberculosis drug pyrazinamide by converting it into the active form, pyrazinoic acid. Mutations in the pncA gene cause pyrazinamide resistance in M. tuberculosis. The properties of M. tuberculosis PncA were characterized in this study. The enzyme was found to be a 20.89 kDa monomeric protein. The optimal pH and temperature of enzymatic activity were pH 7.0 and 40 °C, respectively. Inductively coupled plasma-optical emission spectrometry revealed that the enzyme was an Mn2+/Fe2+ -containing protein with a molar ratio of [Mn2+] to [Fe2+] of 1 : 1; furthermore, the external addition of either type of metal ion had no apparent effect on the wild-type enzymatic activity. The activity of the purified enzyme was determined by HPLC, and it was shown that it possessed similar pyrazinamidase and nicotinamidase activity, by contrast with previous reports. Nine PncA mutants were generated by site-directed mutagenesis. Determination of the enzymatic activity and metal ion content suggested that Asp8, Lys96 and Cys138 were key residues for catalysis, and Asp49, His51, His57 and His71 were essential for metal ion binding. Our data show that M. tuberculosis PncA may bind metal ions in a manner different from that observed in the case of Pyrococcus horikoshii PncA. [source] 7,8-Diaminoperlargonic acid aminotransferase from Mycobacterium tuberculosis, a potential therapeutic targetFEBS JOURNAL, Issue 20 2006Characterization, inhibition studies Diaminopelargonic acid aminotransferase (DAPA AT), which is involved in biotin biosynthesis, catalyzes the transamination of 8-amino-7-oxononanoic acid (KAPA) using S -adenosyl- l -methionine (AdoMet) as amino donor. Mycobacterium tuberculosis DAPA AT, a potential therapeutic target, has been overproduced in Escherichia coli and purified to homogeneity using a single efficient step on a nickel-affinity column. The enzyme shows an electronic absorption spectrum typical of pyridoxal 5,-phosphate-dependent enzymes and behaves as a homotetramer in solution. The pH profile of the activity at saturation shows a single ionization group with a pKa of 8.0, which was attributed to the active-site lysine residue. The enzyme shows a Ping Pong Bi Bi kinetic mechanism with strong substrate inhibition with the following parameters: KmAdoMet = 0.78 ± 0.20 mm, KmKAPA = 3.8 ± 1.0 µm, kcat = 1.0 ± 0.2 min,1, KiKAPA = 14 ± 2 µm. Amiclenomycin and a new analogue, 4-(4c -aminocyclohexa-2,5-dien-1r -yl)propanol (referred to as compound 1), were shown to be suicide substrates of this enzyme, with the following inactivation parameters: Ki = 12 ± 2 µm, kinact = 0.35 ± 0.05 min,1, and Ki = 20 ± 2 µm, kinact = 0.56 ± 0.05 min,1, for amiclenomycin and compound 1, respectively. The inactivation was irreversible, and the partition ratios were 1.0 and 1.1 for amiclenomycin and compound 1, respectively, which make these inactivators particularly efficient. compound 1 (100 µg·mL,1) completely inhibited the growth of an E. coli C268bioA mutant strain transformed with a plasmid expressing the M. tuberculosis bioA gene, coding for DAPA AT. Reversal of the antibiotic effect was observed on the addition of biotin or DAPA. Thus, compound 1 specifically targets DAPA AT in vivo. [source] Structural and thermodynamic insights into the binding mode of five novel inhibitors of lumazine synthase from Mycobacterium tuberculosisFEBS JOURNAL, Issue 20 2006Ekaterina Morgunova Recently published genomic investigations of the human pathogen Mycobacterium tuberculosis have revealed that genes coding the proteins involved in riboflavin biosynthesis are essential for the growth of the organism. Because the enzymes involved in cofactor biosynthesis pathways are not present in humans, they appear to be promising candidates for the development of therapeutic drugs. The substituted purinetrione compounds have demonstrated high affinity and specificity to lumazine synthase, which catalyzes the penultimate step of riboflavin biosynthesis in bacteria and plants. The structure of M. tuberculosis lumazine synthase in complex with five different inhibitor compounds is presented, together with studies of the binding reactions by isothermal titration calorimetry. The inhibitors showed the association constants in the micromolar range. The analysis of the structures demonstrated the specific features of the binding of different inhibitors. The comparison of the structures and binding modes of five different inhibitors allows us to propose the ribitylpurinetrione compounds with C4,C5 alkylphosphate chains as most promising leads for further development of therapeutic drugs against M. tuberculosis. [source] Mycobacterium tuberculosis possesses a functional enzyme for the synthesis of vitamin C, L -gulono-1,4-lactone dehydrogenaseFEBS JOURNAL, Issue 19 2006Beata A. Wolucka The last step of the biosynthesis of l -ascorbic acid (vitamin C) in plants and animals is catalyzed by l -gulono-1,4-lactone oxidoreductases, which use both l -gulono-1,4-lactone and l -galactono-1,4-lactone as substrates. l -Gulono-1,4-lactone oxidase is missing in scurvy-prone, vitamin C-deficient animals, such as humans and guinea pigs, which are also highly susceptible to tuberculosis. A blast search using the rat l -gulono-1,4-lactone oxidase sequence revealed the presence of closely related orthologs in a limited number of bacterial species, including several pathogens of human lungs, such as Mycobacterium tuberculosis, Pseudomonas aeruginosa, Burkholderia cepacia and Bacillus anthracis. The genome of M. tuberculosis, the etiologic agent of tuberculosis, encodes a protein (Rv1771) that shows 32% identity with the rat l -gulono-1,4-lactone oxidase protein. The Rv1771 gene was cloned and expressed in Escherichia coli, and the corresponding protein was affinity-purified and characterized. The FAD-binding motif-containing Rv1771 protein is a metalloenzyme that oxidizes l -gulono-1,4-lactone (Km 5.5 mm) but not l -galactono-1,4-lactone. The enzyme has a dehydrogenase activity and can use both cytochrome c (Km 4.7 µm) and phenazine methosulfate as exogenous electron acceptors. Molecular oxygen does not serve as a substrate for the Rv1771 protein. Dehydrogenase activity was measured in cellular extracts of a Mycobacterium bovis BCG strain. In conclusion, M. tuberculosis produces a novel, highly specific l -gulono-1,4-lactone dehydrogenase (Rv1771) and has the capacity to synthesize vitamin C. [source] A novel thermostable hemoglobin from the actinobacterium Thermobifida fuscaFEBS JOURNAL, Issue 16 2005Alessandra Bonamore The gene coding for a hemoglobin-like protein (Tf-trHb) has been identified in the thermophilic actinobacterium Thermobifida fusca and cloned in Escherichia coli for overexpression. The crystal structure of the ferric, acetate-bound derivative, was obtained at 2.48 Å resolution. The three-dimensional structure of Tf-trHb is similar to structures reported for the truncated hemoglobins from Mycobacterium tuberculosis and Bacillus subtilis in its central domain. The complete lack of diffraction patterns relative to the N- and C-terminal segments indicates that these are unstructured polypeptides chains, consistent with their facile cleavage in solution. The absence of internal cavities and the presence of two water molecules between the bound acetate ion and the protein surface suggest that the mode of ligand entry is similar to that of typical hemoglobins. The protein is characterized by higher thermostability than the similar mesophilic truncated hemoglobin from B. subtilis, as demonstrated by far-UV CD melting experiments on the cyano-met derivatives. The ligand-binding properties of Tf-trHb, analyzed in stopped flow experiments, demonstrate that Tf-trHb is capable of efficient O2 binding and release between 55 and 60 °C, the optimal growth temperature for Thermobifida fusca. [source] The effect of HAMP domains on class IIIb adenylyl cyclases from Mycobacterium tuberculosisFEBS JOURNAL, Issue 12 2004Jürgen U. Linder The genes Rv1318c, Rv1319c, Rv1320c and Rv3645 of Mycobacterium tuberculosis are predicted to code for four out of 15 adenylyl cyclases in this pathogen. The proteins consist of a membrane anchor, a HAMP region and a class IIIb adenylyl cyclase catalytic domain. Expression and purification of the isolated catalytic domains yielded adenylyl cyclase activity for all four recombinant proteins. Expression of the HAMP region fused to the catalytic domain increased activity in Rv3645 21-fold and slightly reduced activity in Rv1319c by 70%, demonstrating isoform-specific effects of the HAMP domains. Point mutations were generated to remove predicted hydrophobic protein surfaces in the HAMP domains. The mutations further stimulated activity in Rv3645 eight-fold, whereas the effect on Rv1319c was marginal. Thus HAMP domains can act directly as modulators of adenylyl cyclase activity. The modulatory properties of the HAMP domains were confirmed by swapping them between Rv1319c and Rv3645. The data indicate that in the mycobacterial adenylyl cyclases the HAMP domains do not display a uniform regulatory input but instead each form a distinct signaling unit with its adjoining catalytic domain. [source] Antibody bound to the surface antigen MPB83 of Mycobacterium bovis enhances survival against high dose and low dose challengeFEMS IMMUNOLOGY & MEDICAL MICROBIOLOGY, Issue 2 2004Mark A. Chambers Abstract Tuberculosis caused by infection with Mycobacterium tuberculosis or Mycobacterium bovis is a significant disease of man and animals. Whilst cellular immunity is the major immunological component required for protection against these organisms, recent reports have suggested that monoclonal antibodies can modify infection with M. tuberculosis. To test whether the same was true for M. bovis infection, we determined the effect of preincubation of M. bovis with a monoclonal antibody on subsequent intravenous infection of mice. Antibodies bound to the surface of M. bovis increased the survival time of mice infected with M. bovis and changed the morphology of granulomas and the distribution of acid-fast bacilli in the lung. These studies suggest that antibodies directed to the surface of virulent mycobacteria can modulate their virulence in vivo. [source] Cell proliferation and apoptosis: dual-signal hypothesis tested in tuberculous pleuritis using mycobacterial antigensFEMS IMMUNOLOGY & MEDICAL MICROBIOLOGY, Issue 1 2004Sulochana D. Das Abstract Antigens and mitogens have the innate ability to trigger cell proliferation and apoptosis thus exhibiting a dual-signal phenomenon. This dual-signal hypothesis was tested with mycobacterial antigens (PPD and heat killed Mycobacterium tuberculosis, MTB) in tuberculous pleuritis patients where the immune response is protective and compartmentalized. We compared and correlated the cell-cycle analysis and antigen-induced apoptosis in normal and patients' peripheral blood mononuclear cells (PBMCs) and patients' pleural fluid mononuclear cells (PFMCs). In cell-cycle analysis, PFMCs showed good mitotic response with PPD and MTB antigens where 10% and 7% of resting cells entered the S and G2/M phases of cell cycle, respectively. This antigen-induced proliferation of PFMCs correlated well with the lymphocyte transformation test (LTT) results. On the other hand, PFMCs also showed 21% of spontaneous apoptosis, which further increased to 43%, by induction with known apoptotic agent like Dexamethasone (DEX) and the mycobacterial antigens PPD and MTB. Further we demonstrated by anti-CD3 induction experiments that prior activation of cells is prerequisite for them to undergo apoptosis. Our results showed that PPD and MTB antigens induced both cell proliferation and apoptosis in PFMCs, which were pre-sensitized to mycobacterial antigens in vivo. Thus the dual-signal phenomenon was operative against these antigens in tuberculous pleuritis. We also demonstrated that the activated cells are more predisposed to apoptosis. [source] Heparin-binding hemagglutinin (HBHA) of Mycobacterium leprae is expressed during infection and enhances bacterial adherence to epithelial cellsFEMS MICROBIOLOGY LETTERS, Issue 2 2009Cristiana Soares De Lima Abstract A heparin-binding hemagglutinin (HBHA) expressed on the surface of Mycobacterium tuberculosis is an antigenic protein that has been implicated in bacterial adherence to epithelial cells and systemic dissemination. In this study, the potential role of the Mycobacterium leprae HBHA (ML-HBHA) homologue in leprosy was investigated. Initially, the in vivo expression of HBHA and its association with the M. leprae cell envelope was confirmed by immunoblotting and proteomic analysis. Mycobacterium leprae recombinant HBHA (rML-HBHA) bound to a heparin,Sepharose column, and its capacity to act as an adhesin was demonstrated in experiments showing that the exogenous addition of the protein to latex beads or to M. leprae cells promotes a dramatic increase in association with epithelial cells. Finally, serum anti-HBHA immunoglobulin G levels were investigated in individuals infected with M. leprae. Altogether, our data indicate that HBHA is recognized during the course of bacterial infection in humans and may play a role in leprosy pathogenesis. [source] Genome dynamics in major bacterial pathogensFEMS MICROBIOLOGY REVIEWS, Issue 3 2009Ole Herman Ambur Abstract Pathogenic bacteria continuously encounter multiple forms of stress in their hostile environments, which leads to DNA damage. With the new insight into biology offered by genome sequences, the elucidation of the gene content encoding proteins provides clues toward understanding the microbial lifestyle related to habitat and niche. Campylobacter jejuni, Haemophilus influenzae, Helicobacter pylori, Mycobacterium tuberculosis, the pathogenic Neisseria, Streptococcus pneumoniae, Streptococcus pyogenes and Staphylococcus aureus are major human pathogens causing detrimental morbidity and mortality at a global scale. An algorithm for the clustering of orthologs was established in order to identify whether orthologs of selected genes were present or absent in the genomes of the pathogenic bacteria under study. Based on the known genes for the various functions and their orthologs in selected pathogenic bacteria, an overview of the presence of the different types of genes was created. In this context, we focus on selected processes enabling genome dynamics in these particular pathogens, namely DNA repair, recombination and horizontal gene transfer. An understanding of the precise molecular functions of the enzymes participating in DNA metabolism and their importance in the maintenance of bacterial genome integrity has also, in recent years, indicated a future role for these enzymes as targets for therapeutic intervention. [source] Efficiency of combined methotrexate/chloroquine therapy in adjuvant-induced arthritisFUNDAMENTAL & CLINICAL PHARMACOLOGY, Issue 4 2005M.A.R.C.P. Silva Abstract The present study evaluates the effects of methotrexate (MTX) and chloroquine (CQ), and of combined MTX + CQ treatment, on the inflammatory response and on plasma and liver phosphatase and transaminase activities, employing an adjuvant-induced arthritis model in rats. Arthritis was induced by the intradermal injection of a suspension of Mycobacterium tuberculosis in mineral oil into the plantar surface of the hind paws. Development of the inflammatory response was assessed over a 21-day period. Animal groups received either: (i) MTX, administered i.p., weekly, in 0.15, 1.5, 3, 6 or 12 mg/kg doses; (ii) CQ, given intragastrically, in daily 25 or 50 mg/kg doses; or (iii) MTX + CQ, administered in two combinations (MTX1.5 mg/kg + CQ50 mg/kg, or MTX6 mg/kg + CQ50 mg/kg). At the end of the experimental period, the animals were anesthetized and killed, blood and liver samples were collected and prepared for measurement of acid and alkaline phosphatase (AP, ALP), and aspartate (AST) and alanine aminotransferase (ALT) activities. MTX at 6 and 12 mg/kg reduced the inflammatory response while CQ had no effect. MTX6 mg/kg + CQ50 mg/kg reduced the inflammatory response similar to MTX12 mg/kg, without affecting the bone marrow. Plasma AP and liver ALP activities were very elevated in the arthritic rats. While MTX treatment partially reduced both plasma AP and liver ALP activities at all doses used in the arthritic rats, CQ treatment reduced plasma AP, but increased liver AP activity. MTX + CQ treatment decreased plasma AP and liver ALP activities in the arthritic rats to control values. Plasma and liver AST activities were unaltered in the arthritic rats, and were unaffected by treatment. However, plasma and liver ALT activities were significantly reduced in the arthritic rats. While MTX or CQ treatment did not alter plasma transaminase activity in the arthritic rats, after MTX + CQ treatment, plasma ALT activity returned to normal values. In conclusion, the present data suggest that MTX + CQ treatment provides more effective anti-inflammatory protection against adjuvant-induced arthritis than does MTX alone, reverting the alterations in enzyme activities induced by this inflammatory disease in rats. [source] Accelerated induction of mycobacterial antigen-specific CD8+ T cells in the Mycobacterium tuberculosis -infected lung by subcutaneous vaccination with Mycobacterium bovis bacille Calmette,GuérinIMMUNOLOGY, Issue 4 2009Dilara Begum Summary Both CD4+ and CD8+ T cells are important in protection against Mycobacterium tuberculosis infection. To evaluate the effect of vaccination with Mycobacterium bovis bacille Calmette,Guérin (BCG) on the CD8+ T-cell response to pulmonary M. tuberculosis infection, we analyzed the kinetics of CD8+ T cells specific to the mycobacterial Mtb32a309,318 epitope, which is shared by M. tuberculosis and M. bovis BCG, in the lung of mice infected with M. tuberculosis. The CD8+ T cells were detected by staining lymphocytes with pentameric major histocompatibility complex (MHC) class I H-2Db,Mtb32a209,318 peptide complex and were analysed by flow cytometry. Mtb32a-specific CD8+ T cells became detectable on day 14, and reached a plateau on day 21, in the lung of M. tuberculosis -infected unvaccinated mice. Subcutaneous vaccination with M. bovis BCG in the footpads induced Mtb32a-specific CD8+ T cells in the draining lymph nodes (LNs) on day 7 and their numbers further increased on day 14. When M. bovis BCG-vaccinated mice were exposed to pulmonaryinfection with M. tuberculosis 4 weeks after vaccination, the Mtb32a-specific CD8+ T cells in the infected lung became detectable on day 7 and reached a plateau on day 14, which was 1 week earlier than in the unvaccinated mice. The pulmonary CD8+ T cells from the BCG-vaccinated M. tuberculosis -infected mice produced interferon-, in response to Mtb32a209,318 peptide on day 7 of the infection, whereas those of unvaccinated mice did not. The results demonstrate that induction of mycobacterial antigen-specific protective CD8+ T cells in the M. tuberculosis -infected lung is accelerated by subcutaneous vaccination with M. bovis BCG. [source] CD14 contributes to pulmonary inflammation and mortality during murine tuberculosisIMMUNOLOGY, Issue 2 2008Catharina W. Wieland Summary Toll-like receptors play an essential role in the innate recognition of micro-organisms by the host. CD14 is one of the extracellular adaptor proteins required for recognition of Gram-negative bacteria and possibly also Mycobacterium tuberculosis. Therefore, we intranasally infected wild-type (WT) and CD14 knock-out (KO) mice with virulent M. tuberculosis H37Rv. We found no differences in bacterial load in the main target organ lung up to 32 weeks after infection. From 20 weeks onward 57% of WT mice succumbed, whereas all CD14 KO mice survived. The improved outcome of CD14 KO mice was accompanied by reduced pulmonary inflammation; lung cell counts and percentage of inflamed lung tissue were reduced in CD14 WT mice. These data suggest that during chronic infection CD14 KO mice are protected from lethality caused by lung tuberculosis because of a reduction of the inflammatory response. [source] Differential CD4+ T-cell memory responses induced by two subsets of human monocyte-derived dendritic cellsIMMUNOLOGY, Issue 3 2007Sandra Bajaña Summary Dendritic cells (DC) are powerful inducers of primary T-cell responses, but their role in secondary responses has not been extensively analysed. Here, we address the role of two DC subsets derived from human CD16+ (16+ mDC) or CD16, (16, mDC) monocytes on the reactivation of memory responses. CD4+ CD45RA, memory T cells were obtained from adult blood donors, and central (TCM) and effector (TEM) memory T cells were isolated by fluorescence-activated cell sorting with anti-CCR7 antibodies. The 16+ mDC and 16, mDC were cocultured with autologous lymphocytes, either unpulsed or loaded with purified protein derivatives of Mycobacterium tuberculosis (PPD) or tetanus toxoid (TT), and were analysed for up to 8 days. Over a range of doses, 16+ mDC drove stronger T-cell proliferative responses against both antigens. Overall, antigen-specific memory cells tended to acquire a phenotype of TEM at later time-points in the culture, whereas cells that had completed fewer cycles of division were similar to TCM. The 16+ mDC induced higher rates of proliferation on both TCM and TEM lymphocytes than 16, mDC. This phenomenon was not related to the ability of both DC to induce CD25 expression on T cells, to lower secretion of interleukin-2, or to raise production of interleukin-10 during T-cell/16, mDC cocultures. The induction of TCM effector capacity in terms of interferon-, production was faster and more pronounced with 16+ mDC, whereas both DC had similar abilities with TEM. In conclusion, these data might reveal new potentials in vaccination protocols with 16+ mDC aimed at inducing strong responses on central memory T cells. [source] Airways infection with virulent Mycobacterium tuberculosis delays the influx of dendritic cells and the expression of costimulatory molecules in mediastinal lymph nodesIMMUNOLOGY, Issue 4 2004Gina S. García-Romo Summary Despite tuberculosis resurgence and extensive dendritic cell (DC) research, there are no in vivo studies evaluating DC within regional lymphoid tissue during airways infection with virulent Mycobacterium tuberculosis (Mtb) H37Rv. Using DC-specific antibodies, immunocytochemistry, flow cytometry and Ziehl,Neelsen (ZN) for bacilli staining, we searched for Mtb and DC changes within mediastinal lymph nodes, after intratracheal (ITT) inoculation of virulent Mtb. ZN and immunocytochemistry in frozen and paraffin sections of mediastinal lymph nodes identified Mtb until day 14 after ITT inoculation, associated with CD11c+ and Dec205+ DC. Analysing CD11c, MHC-CII, and Dec205 combinations by flow cytometry in MLN suspensions revealed that CD11c+/MHC-CII+ and CD11c+/Dec205+ DC did not increase until day 14, peaked on day 21, and sharply declined by day 28. No changes were seen in control, saline-inoculated animals. The costimulatory molecules evaluated in CD11c+ DCs followed a similar trend; the CD80 increase was negligible, slightly surpassed by CD40. CD86 increased earlier and the three markers peaked at day 21, declining by day 28. While antigen-specific proliferation was not evident for MLN CD4+ T cells at 2 weeks postinfection, delayed-type hypersensitivity responses upon ITT inoculation revealed that, as early as day 3 and 7, both the priming and peripheral systemic immune responses were clearly established, persisting until days 14,21. While airways infection with virulent Mtb triggers an early, systemic peripheral response maintained for three weeks, this seems dissociated from regional events within mediastinal lymph nodes, such as antigen-specific T-cell reactivity and a delay in the influx and local activation of DC. [source] Increased expression of mRNA encoding interleukin (IL)-4 and its splice variant IL-4,2 in cells from contacts of Mycobacterium tuberculosis, in the absence of in vitro stimulationIMMUNOLOGY, Issue 4 2004Helen A. Fletcher Summary Expression of interleukin (IL)-4 is increased in tuberculosis and thought to be detrimental. We show here that in healthy contacts there is increased expression of its naturally occurring antagonist, IL-4delta2 (IL-4,2). We identified contacts by showing that their peripheral blood mononuclear cells (PBMC) released interferon (IFN)-, in response to the Mycobacterium tuberculosis -specific antigen 6 kDa early secretory antigenic target (ESAT-6). Fresh unstimulated PBMC from these contacts contained higher levels of mRNA encoding IL-4,2 (P=0·002) than did cells from ESAT-6 negative donors (noncontacts). These data indicate that contact with M. tuberculosis induces unusual, previously unrecognized, immunological events. We tentatively hypothesize that progression to active disease might depend upon the underlying ratio of IL-4 to IL-4,2. [source] Role of chemokine ligand 2 in the protective response to early murine pulmonary tuberculosisIMMUNOLOGY, Issue 4 2003Andre Kipnis Summary Chemokines play an important role in the development of immunity to tuberculosis. Chemokine ligand 2 (CCL2, JE, monocyte chemoattractant protein-1) is thought to be primarily responsible for recruiting monocytes, dendritic cells, natural killer cells and activated T cells, all of which play critical roles in the effective control of tuberculosis infection in mice. We show here that in mice in which the CCL2 gene was disrupted, low-dose aerosol infection with Mycobacterium tuberculosis resulted in fewer macrophages entering the lungs, but only a minor and transient increase in bacterial load in the lungs; these mice were still able to establish a state of chronic disease. Such animals showed similar numbers of activated T cells as wild-type mice, as determined by their expression of the CD44hi CD62lo phenotype, but a transient reduction in cells secreting interferon-,. These data indicate that the primary deficiency in mice unable to produce CCL2 is a transient failure to focus antigen-specific T lymphocytes into the infected lung, whereas other elements of the acquired host response are compensated for by different ligands interacting with the chemokine receptor CCR2. [source] Recent advances in medical dermatologyINTERNATIONAL JOURNAL OF DERMATOLOGY, Issue 10 2007Lily N. Clark MD Collectively, new developments in the field of medical dermatology will ultimately lead to improved patient care. We review several new findings in the dermatologic literature including the following: new questions regarding the malignant potential of anti-tumor necrosis factor agents, which are widely used for the treatment of moderate to severe psoriasis as well as psoriatic arthritis; anti-interleulin-12, a promising anticytokine for the treatment of psoriasis; diagnostic advances in the detection of latent Mycobacterium tuberculosis; advances in the primary prevention of human papillomavirus and herpes zoster; and new therapeutic options with existing medications for neuropathic pain and pruritus. [source] Erythema induratum with pulmonary tuberculosis: histopathologic features resembling true vasculitisINTERNATIONAL JOURNAL OF DERMATOLOGY, Issue 3 2001Yong Suk Lee MD A 22-year-old South Korean woman presented with a 4-month history of several nodules on both legs. She looked healthy, but suffered from tenderness and swelling of the legs. Physical examination showed multiple, nonulcerating, erythematous nodules occurring on the calves, knee joints, and thighs (Fig. 1). A biopsy specimen of the skin revealed necrotizing vasculitis of medium-sized arteries with fibrinoid necrosis at the border between the dermis and the subcutis. Dense cellular infiltrates, including numerous neutrophils and lymphocytes, presented within and around the vessel walls as in polyarteritis nodosa, with some eosinophils (Fig. 2A,B). There were no other generalized symptoms. She was diagnosed with cutaneous polyarteritis nodosa and was initially treated with systemic steroids. She was given an intravenous injection of Solu-Cortef, 60 mg/6 h for 7 days. This was replaced with oral prednisolone for 2 weeks. The skin lesions and symptoms improved. Figure 1. Small, nut-sized, erythematous, brown-colored nodules and patches on the lower extremities, even above the knee joints Figure 2. (A) Dense infiltration within and around artery (× 40). (B) Slightly expanded lobular panniculitis with vasculitis (× 100) Six months later, she complained of general weakness and recurrent skin lesions. Purified protein derivative (PPD) test gave a moderate positive reaction and chest X-ray examination showed the features of pulmonary tuberculosis: radio-opaque infiltrations in the right lower lung field. A repeated biopsy revealed mild vasculitis with more diffuse lobular infiltrations of the subcutaneous tissue compared with the former specimen. Polymerase chain reaction (PCR) and tissue culture for Mycobacterium tuberculosis were performed from a biopsy specimen. DNA was extracted from skin tissue with an AplisystemTM DNA/RNA detection kit using the resin-mediated boiling method (Stargene, Seoul, South Korea). The primers were designed on the basis of the M. tuberculosis gene IS6110 target (sense primer, 5,-CCA GAT GCA CCG TCG AAC GGC TGA T-3, antisense primer, 5,-CGC TCG CTG AAC CGG ATC GAT GTG T-3,). The amplification was performed with uracil- N -glycosylase (UNG), to prevent carry-over contamination, and internal control primers, to correct for false-negative reaction (Kox LF, Rhienthong D, Miranda AM et al. A more reliable PCR for detection of Mycobacterium tuberculosis in clinical samples. J Clin Microbiol 1994; 32: 672,678; Longo MC, Berninger MS, Hartley JL. Use of uracil DNA glycosylase to control carry-over contamination in polymerase chain reactions. Gene 1990; 93: 125,128). According to the manufacturer's instructions, amplification was carried out for 40 cycles with denaturation at 94 °C for 40 s, annealing at 70 °C for 1 min, and extension at 72 °C for 1 min in a thermal cycler (Perkin,Elmer Cetus, Norwalk, CT, USA). The results of PCR and tissue culture for M. tuberculosis using the biopsy specimen were all negative (Fig. 3). Figure 3. Negative result in PCR for M. tuberculosis (negative control is not shown; M, marker; P, positive control; I, internal control; S, specimen) The patient was finally diagnosed with erythema induratum with pulmonary tuberculosis and was started on antituberculosis medication (isoniazid 400 mg, rifampicin 600 mg, ethambutol 800 mg, and pyrazinamide 1500 mg daily). She showed prompt improvement after 2 weeks of medication. After 9 months of antituberculosis therapy, her skin lesions and chest X-ray had cleared. She was followed up for 4 months with no recurrence of skin and pulmonary lesions. [source] Pathological and immunological profiles of rat tuberculosisINTERNATIONAL JOURNAL OF EXPERIMENTAL PATHOLOGY, Issue 3 2004Isamu Sugawara Summary To investigate the pathological and immunological profiles of rat tuberculosis, Lewis female rats were infected aerially with Mycobacterium tuberculosis. Histopathology, immunological profiles of mononuclear cells from M. tuberculosis -infected rat lung tissue, and the expression patterns of cytokine and iNOS mRNAs were examined over time. M. tuberculosis induced granulomatous lesions in the lungs, spleen, lymph nodes and liver, but these lesions lacked central necrosis. Multinucleate giant cells were observed in late-phase tuberculosis. CD4+ and CD8+ T cells increased with time and reached a peak 5 weeks after infection, decreasing gradually thereafter. ED1 antigen, suggestive of alveolar macrophages, was expressed at a high level in early phase tuberculosis and remained at the same level even in the late phase. OX62 antigen increased gradually and reached a peak 5 weeks after infection. Interferon-,, tumour necrosis factor-, and iNOS mRNAs were expressed strongly over time, but their expression decreased 12 weeks after infection. Because rat tuberculosis is very similar to murine tuberculosis and it is easy to obtain mononuclear cells from M. tuberculosis -infected rat lung tissue, the rat tuberculosis model appears to be suitable for immunological studies in vivo. [source] Tubercular pyomyositis in a case of rheumatoid arthritis being treated with infliximabINTERNATIONAL JOURNAL OF RHEUMATIC DISEASES, Issue 1 2010Pooja KHOSLA Abstract A 55-year-old woman with rheumatoid arthritis having 4 months previously received two doses of infliximab, presented with fever, hypotension and swelling of right thigh posterolaterally. CT-guided aspiration was performed from the right thigh and revealed acid-fast bacilli (AFB) +++ and mycobacterial culture grew Mycobacterium tuberculosis. The patient improved on anti-tubercular treatment. [source] Bacillus Calmette-Guérin-pulsed dendritic cells stimulate natural killer T cells and ,,T cellsINTERNATIONAL JOURNAL OF UROLOGY, Issue 6 2007Michio Naoe Background: Immunotherapy with bacillus Calmette-Guérin (BCG) for bladder cancer is successful, although the precise mechanism is unclear. Natural killer (NK) cells are a candidate for BCG-activated killer cells, but the roles of other T lymphocytes, such as NKT cells and ,,T cells, are not fully understood. Mycobacterium tuberculosis is a potent activator of both NKT cells and ,,T cells. However, it is known that the patient's prognosis is good if there are increased numbers of dendritic cells (DCs) in the urine after BCG therapy. Therefore, we investigated whether DCs are matured by BCG and whether BCG-pulsed DCs stimulate NKT cells and ,,T cells. Methods: Naïve Pan T cells were isolated form peripheral blood mononuclear cells (PBMCs) and DCs were obtained by culturing CD14+ monocytes with granulocyte,macrophage colony-stimulating factor and interleukin-4. The DCs were pulsed with BCG and their maturation was measured by fluorescence-activated cell sorter analysis using the CD86 antibody. Naïve T lymphocytes were stimulated by coculture with BCG-pulsed DCs in vitro, followed by FACS analysis to estimate the ratio and activation of NKT cells and the ratio of ,,T cells. The 51Cr (chromium) release assay was used to estimate the cytotoxic activity of the stimulated T cells. Cytolytic proteins in the patient's PBMCs were measured during BCG therapy using semiquantitative reverse transcriptase-polymerase chain reaction. Results: The DCs were matured by BCG stimulation and the number of NKT cells and ,,T cells increased after culturing with BCG-pulsed DCs. The BCG-pulsed DCs also activated the NKT cells and ,,T cells. Also, the lymphocytes that were cocultured with the BCG-pulsed DCs showed unspecific cytotoxic activity against a bladder cancer cell line. Conclusion: Sensitization of NKT cells and ,,T cells by BCG-pulsed DCs might be one of the mechanisms of BCG immunotherapy. [source] Regulation of nitrogen metabolism in Mycobacterium tuberculosis: A comparison with mechanisms in Corynebacterium glutamicum and Streptomyces coelicolorIUBMB LIFE, Issue 10 2008Catriona Harper Abstract The mechanisms governing the regulation of nitrogen metabolism in Corynebacterium glutamicum and Streptomyces coelicolor have been extensively studied. These Actinomycetales are closely related to the Mycobacterium genus and may therefore serve as a models to elucidate the cascade of nitrogen signalling in other mycobacteria. Some factors involved in nitrogen metabolism in Mycobacterium tuberculosis have been described, including glutamine synthetase and its adenylyltransferase, but not much data concerning the other components involved in the signalling cascade is available. In this review a comparative study of factors involved in nitrogen metabolism in C. glutamicum and S. coelicolor is made to identify similarities with M. tuberculosis on both a genomic and proteomic level. This may provide insight into a potential global mechanism of nitrogen control in Mycobacterium tuberculosis. © 2008 IUBMB IUBMB Life, 60(10): 643,650, 2008 [source] | ||||||||||||||||||||||||||||||||||