Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0026918 (Mycobacterium)
 52,428 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The crucial clinical problem in leprosy is represented by episodes of intense inflammation that produce nerve damage. When Mycobacterium leprae has been eliminated by means of antibiotics, the death of the bacteria is not a complete solution to the damage caused in nerves. Two of the more frequent immunopathological phenomena in Hansen's disease are Type I, reactions, known as Reversal Reactions (RR), and Type II reactions, of which the most frequent and well known are those called Erythema Nodosum Leprosum (ENL). Type II reactions have been defined as an immunologic complication in multibacillary patients. Both types of reactions are accompanied mainly by the increase of pro-inflammatory cytokines TNF-alpha, IL-1, IL-2, IL-4, IL-6, IL-8, INF-gamma, IL-10, IL-12, among others. In a retrospective analysis of a population of 150 patients of the Central Service of Dermatology, Institute of Biomedicine, where these patients were subjected to Multidrug Therapy (MDT) and MDT + inmunotherapy (IMT), both groups presented type II reactions, but the group that additionally received inmunotherapy also presented type I reactions. In the group of patients that presented ENL, it appeared to be associated with the large amount of bacilli in their lesions.
 ...
PMID:[Some immunological aspects in the reaccional states of Hansen disease]. 1635 45

Human pulmonary tuberculosis (TB) is a worldwide public health problem, which is caused by Mycobacterium tuberculosis. It is a fact that one third of the world's population is infected with this mycobacteria, however, only a minority of people infected by M. tuberculosis may develop a clinical disease. In general, about 90% have their bacilli under control in a latent state throughout their lives by means of their immune responses. About 5% will develop primary progressive TB and the remaining 5% will develop the disease in the later stages of their lives, which is known as reactivation or post-primary TB. In resistant individuals, control of the infection mainly requires development of a Th1 cell immunity response. This type of response involves participation of alveolar macrophages and T CD4+, CD8+ and T gammadelta lymphocytes, and production of cytokines such as IL-2, IFN-gamma, IL-12, IL-18 and TNF-alpha, as well as chemokines such as RANTES, MCP-1, MIP-1alpha and IL-8 which play an important role in the migration of different cell subpopulations to the infection site for the formation of granulome. In addition, the role of "natural killer" (NK) cells, along with epitelial cells, is essential as part of the innate immune response.
 ...
PMID:[Cell immunity response in human pulmonary tuberculosis. Review]. 1635 46

Recently, mouse models for latent (LTB) and slowly progressive primary tuberculosis (SPTB) have been established. However, cytokine profiles during the two models are not well established. Using quantitative reverse transcription-polymerase chain reaction (qRT-PCR) we studied the expression levels of interleukin (IL)-2, IL-4, IL-10, IL-12, IL-15, interferon (IFN)-gamma and tumour necrosis factor (TNF)-alpha during the course of LTB and SPTB in the lungs and spleens of B6D2F1Bom mice infected with the H37Rv strain of Mycobacterium tuberculosis (Mtb). The results show that, except for IL-4, cytokine expression levels were significantly higher during SPTB than LTB in both the lungs and spleens. During LTB, all the cytokines (except IL-2 in the lungs) had higher expression levels during the initial period of infection both in the lungs and spleens. During SPTB, the expression levels of IL-15 increased significantly from phases 1 to 3 in the lungs. The expression levels of IL-10, IL-12 and IFN-gamma increased significantly from 2 to 3 in the lungs. IL-10 and IL-15 increased significantly from phases 2 to 3, whereas that of TNF-alpha decreased significantly and progressively from phases 1 to 3 in the spleens. Over-expression of proinflammatory cytokines during active disease has been well documented, but factor(s) underlying such over-expression is not known. In the present study, there was a progressive and significant increase in the expression levels of IL-15, together with Th1 cytokines (IL-12 and IFN-gamma) during SPTB but a significant decrease during LTB. IL-15 is known to up-regulate the production of proinflammatory cytokines, IL-1beta, IL-8, IL-12, IL-17, IFN-gamma and TNF-alpha and has an inhibitory effect on activation-induced cell death. IL-15 is known to be involved in many proinflammatory disease states such as rheumatoid arthritis, sarcoidosis, inflammatory bowel diseases, autoimmune diabetes, etc. Our results, together with the above observations, suggest that IL-15 may play an important role in mediating active disease during Mtb infection.
 ...
PMID:Cytokine profile during latent and slowly progressive primary tuberculosis: a possible role for interleukin-15 in mediating clinical disease. 1636 49

Tuberculosis is the most frequent coinfection in humans infected with HIV-1, but little is known about mechanisms that favors coinfection. The aim of this work is to understand tuberculosis and HIV infections. We determined the pattern of expression of CD11c, CD14, CD40, CCR5, and CXCR4 and quantified IL-1beta, IL-6, IL-8, TNF-alpha, and RANTES in tuberculosis patients and HIV patients. Monocytes from healthy PPD+ volunteers (HP(+)V) stimulated with intracellular proteins (IP), lipids, and polysaccharides (PLS) from Mycobacterium tuberculosis down regulate CD11c expression (p < 0.05). On the contrary, CD14 expression was elevated in tuberculosis patients (p < 0.05) and HIV-infected patients (p > 0.05). CD14 expression was elevated on monocytes from HP(+)V stimulated with PLS and lipids (p < 0.05). CD40 low expression was found in tuberculosis patients and on monocytes from HP(+)V stimulated with lipids, but it was elevated in HIV-infected patients (p < 0.05). CXCR4 and CCR5 expression was high in pulmonary tuberculosis patients and low in HIV-infected patients (p < 0.05). Finally, CCR5+ monocytes from HP(+)V after stimulation with PLS and CXCR4+ lymphocytes were elevated after stimulation with IP (p < 0.05). In general, high levels of IL-1beta, IL-6, and TNF-alpha were found in all groups, but low levels of RANTES were found in pulmonary tuberculosis patients. In conclusion, the pulmonary tuberculosis patients have a microenvironment that facilitates the HIV infection through three possible mechanisms: (1) increasing the coreceptor for HIV entrance, (2) increasing proinflammatory cytokines, and (3) down-regulating RANTES. At the same time, HIV patients have a microenvironment that facilitates entry of M. tuberculosis into macrophages through CD14.
 ...
PMID:Mycobacterium tuberculosis upregulates coreceptors CCR5 and CXCR4 while HIV modulates CD14 favoring concurrent infection. 1643 45

Bacterial DNA has a variety of immunostimulatory activities, such as the activation of B cells and natural killer cells, the induction of interferon-gamma, and the induction of Th1-type immune responses. In contrast, mammalian DNA does not have these activities. To evaluate the genomic DNA sequences of Mycobacterium bovis that have immunostimulatory activity, we used a computer to analyze the M. bovis genome and we designed a series of synthetic, 20 base length, phosphodiester backbone oligodeoxynucleotides (ODNs) that contain CpG motifs (MB-ODNs). We screened the immunostimulatory MB-ODNs that induce the activation of the NF-kappaB-responsive IL-8 promoter in RAW 264.7 cells. Our experimental analyses demonstrate that the potent CpG DNA in the M. bovis genome has functional effects as a Th1-responsive adjuvant, and that it activates the transcription factor NF-kappaB. Moreover, we found that both the CpG motifs and the context of the sequence surrounding the CpG motif are important for the immunostimulatory activities. The identification of the potent immunostimulatory DNA sequence in a native bacterial genome may give insights to the optimal sequence for well-controlled immune responses.
 ...
PMID:Immunostimulatory oligodeoxynucleotide isolated from genome wide screening of Mycobacterium bovis chromosomal DNA. 1644 22

Mycobacterium leprae and Mycobacterium tuberculosis are successful intracellular pathogens which down regulate host immune responses. T-cell interferon-gamma (IFNgamma) and macrophage tumour necrosis factor-alpha (TNFalpha) activate chemokines such as, C-C chemokine ligand-2 (CCL2) and CCL5, which play a role in granuloma formation. Lepromatous leprosy is characterized by defective granulomas with lowered T-cell- and macrophage-mediated responses. Tuberculosis (TB) can be localized to the lung, whereby discreet granulomas are formed. The role of chemokines in leprosy infections is as yet unclear. We compared chemokine responses in lepromatous leprosy and pulmonary tuberculosis patients. Circulating serum CCL2 was raised while CCL5 was lowered in leprosy, as compared with TB patients and healthy controls. However, both Mycobacterium bovis BCG- (P=0.08) and M. leprae-induced (P=0.05) CCL2 secretion was reduced in leprosy. In leprosy, BCG induced greater CCL2 (P=0.01), TNFalpha (P=0.02) and somewhat greater CCL5 (P=0.08) than M. leprae, while CXCL8 induction was comparable. Overall levels of Mycobacterium-induced CCL2, TNFalpha and CXCL8 were two to threefold lower, and CCL5 was 10-fold lower in leprosy as compared with TB. Reduced inducible CCL2 combined with a lowered TNFalpha response in lepromatous leprosy may contribute to the unrestricted growth and dissemination of mycobacteria found in the disease.
 ...
PMID:Elevated serum CCL2 concomitant with a reduced mycobacterium-induced response leads to disease dissemination in leprosy. 1649 78

Cytokine mRNA expression in biopsies of Mycobacterium ulcerans-infected human tissue was investigated using real-time PCR, and the findings were correlated with the clinical stages of disease and histopathologies. A broad range of cytokine mRNAs were detected in 16 early nodules and 28 late-stage ulcers, including those for the Th1 cytokines tumor necrosis factor alpha (TNF-alpha) and gamma interferon (IFN-gamma) and the Th2 cytokine interleukin 10 (IL-10). IFN-gamma was strongly expressed in both nodules and ulcers, suggesting that a Th1 response begins early in the disease. There was a significantly higher expression of IL-8 and other proinflammatory cytokines in results from 32 biopsies with neutrophilia than in those from 12 biopsies without acute inflammation. Ten tissue samples containing granulomas showed high mRNA expression for IFN-gamma, IL-1beta, IL-12p35, IL-12p40, IL-15, and TNF-alpha relative to 34 tissue samples without granulomas. These results suggest that the human immune response to M. ulcerans is similar to that seen with some other mycobacteria despite the presence of the toxin mycolactone in the tissues.
 ...
PMID:Cytokine mRNA expression in Mycobacterium ulcerans-infected human skin and correlation with local inflammatory response. 1662 30

Infection with Mycobacterium bovis is a significant human and animal health problem in many parts of the world. The first stage of pulmonary tuberculosis occurs after inhalation of the bacilli into an alveolus where they are ingested by resident macrophages. DNA microarray analysis was used to detect genes expressed in bovine lung alveolar macrophages infected with two isogenic strains of M. bovis, a virulent strain, ATCC35723 and an attenuated strain, WAg520 derived from ATCC35723. Chemokines, interleukin-8 and monocyte chemotactic protein 1, were more strongly expressed in ATCC35723-infected macrophages compared to WAg520-infected macrophages. Conversely, a group of genes, including fibrinogen-like protein 2 and legumain, were expressed at a higher level in macrophages infected with WAg520 compared to ATCC35723. Quantitative real-time PCR of a selected group of these differentially expressed genes confirmed enhanced levels of IL-8 mRNA in ATCC35723-infected macrophages compared to WAg520-infected macrophages. Microarray analysis of gene expression in macrophages infected with attenuated isogenic strains of M. bovis may identify key genes involved in early and protective immune responses to tuberculosis.
 ...
PMID:Differences of gene expression in bovine alveolar macrophages infected with virulent and attenuated isogenic strains of Mycobacterium bovis. 1664 81

The aim of the present study was to determine the effects of stimulation of sonicated Mycobacterium leprae (MLS) extract and phorbol myristate acetate (PMA) on the pattern of cytokine production in peripheral blood mononuclear cells (PBMC) and to find out whether there is any difference between stimulation of MLS extract and PMA. Blood samples were collected and PBMC isolated from 43 inactive lepromatous leprosy patients. After culture for 24 hours, lymphocytes were stimulated with MLS extract and PMA. In the culture supernatant, IL-2, 4, 6, 8, TNF-alpha and TGF-beta levels were measured by using ELISA. M. leprae stimulated group IL-6, IL-8, TNF-alpha, TGF-beta levels were found significantly higher than PMA stimulated group (P < 0.05). However, there was no difference between the two groups for IL-4. Only IL-2 levels were higher in PMA stimulated group than M. leprae stimulated group. Sonicated M. leprae extract have a strong effect on cytokine levels in vitro. Our results suggest that antigens with varying specificities favour the production of distinct cytokine patterns following in vitro restimulation.
 ...
PMID:Cytokine measurement in lymphocyte culture supernatant of inactive lepromatous leprosy patients. 1668 63

The Rv3083-Rv3089 operon of Mycobacterium tuberculosis has been shown to be induced 17-33-fold when tubercle bacilli were exposed in vitro to acidic conditions which may mimic those that the bacilli encounter early during the infection and it is induced during growth in macrophages. To understand the role of this operon in intracellular survival, we constructed a knockout of the operon in the M. tuberculosis H37Rv strain. No differences were observed in the growth of mutant and wild-type mycobacteria on axenic media. Though the uptake of mutant and wild-type bacteria by eukaryotic cells was similar, the mutant failed to grow subsequently. By 192h post-infection, the fold differences between the wild-type and mutant bacteria were significant thus leading to the conclusion that the mutant is defective for intracellular growth in these cell lines. Complementation of the knockout restored intracellular growth to wild-type levels. During the first 24-48h post-infection, mutant bacteria also stimulated production of significantly less IL-1beta, IL-6, IL-8, RANTES, and MCP-1 by THP-1 cells than wild-type bacteria. Overall, the data indicate that the operon plays an important role in the ability of M. tuberculosis to grow inside host cells.
 ...
PMID:The acid-induced operon Rv3083-Rv3089 is required for growth of Mycobacterium tuberculosis in macrophages. 1689 82


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>