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Query: UMLS:C0026918 (Mycobacterium)
 52,428 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The results of this study show that clinical isolates of Mycobacterium avium fall into two categories in terms of their capacity to grow within murine bone marrow-derived macrophage cultures: those that grow progressively and those that are incapable of growing within such cells. Members of the first category were invariably of the smooth-transparent colonial type, while most of the second were of the smooth-doomed type. In addition, this paper shows that although all isolates induced tumor necrosis factor (TNF) secretion by host cells to some extent, this production was always delayed in isolates that subsequently grew well in the host cells. This observation, coupled with the demonstration that the growth of the latter isolates was inhibited by the exogenous addition of TNF, leads us to hypothesize that the ability of a given isolate to somehow avoid host macrophage TNF production early during the course of the infection is a key factor in the pathogenesis of the disease.
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PMID:Capacity of Mycobacterium avium isolates to grow well or poorly in murine macrophages resides in their ability to induce secretion of tumor necrosis factor. 139 51

The quantitative relationships among the in vitro lymphocyte proliferation in peripheral blood in 19 healthy donors to purified protein derivative (PPD) and the killed Mycobacterium tuberculosis, interferon-gamma (IFN gamma) and tumor necrosis factor-alpha (TNF alpha) production in these culture supernatants, and the in vivo skin reaction to PPD which were simultaneously measured were studied. Statistical analysis was performed with t-test and multiple regression analysis: The results obtained were as follows; 1) The magnitude of the in vitro lymphocyte proliferation by PPD and the killed M. tuberculosis failed to correlate with the erythema and the induration of the in vivo skin reaction to PPD. 2) The erythema of skin test correlates with TNF alpha production in the culture supernatants that the lymphocytes in peripheral blood were cocultured with these antigens for 7 days. (R = 0.566062, 0.01 less than p less than 0.02) 3) There is a correlation between the erythema and the induration of skin test. (R = 0.526662, 0.02 less than p less than 0.05). 4) Though the magnitude of the lymphocyte proliferation to PPD correlates IFN gamma production in the culture supernatants (R = 0.525915, 0.02 less than p less than 0.05), these response to the killed M. tuberculosis correlates both IFN gamma production (R = 0.55049, 0.01 less than p less than 0.02) and TNF alpha production (R = 0.51283, 0.02 less than p less than 0.05) in the culture supernatants.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[Correlation of tuberculin skin reaction with lymphocyte proliferation, interferon-gamma production and tumor necrosis factor-alpha production after in vitro stimulation with PPD and killed Mycobacterium tuberculosis using peripheral blood of healthy donors]. 143 16

The 1991 literature on septic arthritis included a concise review of adult septic arthritis, examples of pseudoseptic arthritis, and two interesting animal studies. One animal study examined the induction of acute synovitis by the intra-articular injection of bacterial endotoxin and the cytokines tumor necrosis factor-alpha, and interleukin-1 beta; and the other studied the effects of early and delayed synovectomy in the management of septic arthritis. The predispositions to septic arthritis can be divided into local joint abnormalities, systemic factors, or both. Examples of the local joint abnormalities include osteoarthritis of the hip and apatite-associated arthropathy. Septic arthritis in a patient with rheumatoid arthritis, in a patient with diabetes mellitus and hip arthropathy associated with hemochromatosis, or in a patient with acquired immunodeficiency syndrome and hemophilic arthropathy are examples of how systemic predisposition is coupled with local joint pathology to increase the vulnerability of the host to joint infection. Other examples of systemic disease that predispose to septic arthritis are systemic lupus erythematosus, hypogammaglobulinemia, and human immunodeficiency virus infection, as well as intravenous drug abuse. Unusual microorganisms causing septic arthritis in the adult include Achromobacter xylosoxidans, Moraxella catarrhalis, meningococci, and diphtheroids. Uncommon pathogenesis is represented by a case of intra-articular inoculation of Mycobacterium gastri into the small joint of the hand and a case of mixed bacterial infection of the hip resulting from an extension of a contiguous pelvic infection associated with trauma. Two cases of immune complex glomerulonephritis illustrate the extra-articular complications of septic arthritis: one due to group G streptococcus and the other due to pneumococcus. Finally, septic bursitis is reviewed from the community practice perspective.
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PMID:Bacterial arthritis. 150 74

The manifestations of tuberculous infection reflect the immune response to infection. Most healthy tuberculin reactors develop protective immunity; tuberculous pleuritis reflects a resistant response manifest by mild disease, whereas advanced pulmonary and miliary tuberculosis reflect ineffective immunity. The role of gamma delta T cells was assessed in tuberculous infection by evaluating expansion of these cells from blood mononuclear cells after stimulation with Mycobacterium tuberculosis. After culture in vitro, the percentages of gamma delta+ cells were significantly greater in patients with protective and resistant immunity (tuberculin reactors, 25% +/- 4%; tuberculous pleuritis, 30% +/- 7%) than in those with ineffective immunity (advanced pulmonary tuberculosis, 9% +/- 3%; miliary tuberculosis, 2% +/- 1%). In leprosy, expansion of gamma delta+ cells was greater in immunologically resistant tuberculoid patients (32% +/- 4%) than in Mycobacterium leprae-unresponsive lepromatous patients (9% +/- 2%). M. tuberculosis-reactive gamma delta T cell lines produced interferon-gamma, granulocyte-macrophage colony-stimulating factor, interleukin-3, and tumor necrosis factor-alpha, cytokines that activate macrophages and may contribute to mycobacterial elimination. These findings suggest that gamma delta T cells contribute to immune resistance against M. tuberculosis.
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PMID:Gamma delta T lymphocytes in human tuberculosis. 153 55

The results of this study show that lipoarabinomannans (LAM) isolated from a virulent strain and from an avirulent strain of Mycobacterium tuberculosis, which have recently been shown to differ markedly in terms of the structures of their nonreducing termini, also differ markedly in the capacity to induce the secretion of tumor necrosis factor from murine macrophages. It was found that LAM from the avirulent H37Ra strain was 100-fold more potent at inducing tumor necrosis factor secretion than LAM from the virulent Erdman strain, thus leading us to hypothesize that the structure of LAM from a given mycobacterial isolate may directly influence its ability to elicit, or avoid, cytokine-mediated mechanisms of host resistance.
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PMID:Structural basis of capacity of lipoarabinomannan to induce secretion of tumor necrosis factor. 154 42

The spectrum of host responses to Mycobacterium leprae provides a model for investigating the role of cytokines in the pathogenesis of mycobacterial disease. Of particular interest is tumor necrosis factor (TNF), a cytokine which may have both antimycobacterial and immunopathologic effects. To evaluate the potential role of TNF in leprosy, we measured TNF production in response to M. leprae and its defined constituents by peripheral blood mononuclear cells from patients across the spectrum of disease. The levels of TNF induced through the stimulation of cells with M. leprae or its dominant "lipopolysaccharide," lipoarabinomannan, were higher in patients with the tuberculoid form of the disease than in those with the lepromatous form. In patients with erythema nodosum leprosum (ENL), a reactional state of lepromatous leprosy, the levels of TNF release by peripheral blood mononuclear cells were higher than in any other form of the disease. Treatment of ENL patients with thalidomide reduced TNF secretion by more than 90%. The mycolylarabinogalactan-peptidoglycan complex of Mycobacterium species, the protein-peptidoglycan complex, and muramyl dipeptide all elicited significant TNF release. Therefore, TNF release appears to be triggered by at least two major cell wall structural constituents of M. leprae, lipoarabinomannan and segments of the cell wall skeleton. The prominent TNF release in patients with the paucibacillary tuberculoid form of the disease compared with that in patients with the multibacillary lepromatous form suggests that this cytokine contributes to a resistant immune response to mycobacterial infection. However, the marked TNF release in patients with ENL indicates that TNF may also mediate immunopathologic effects, such as fever and tissue damage.
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PMID:Tumor necrosis factor production in patients with leprosy. 154 69

Tuberculosis is a major cause of mortality worldwide and incidence is increasing as a result of the AIDS epidemic. Cytokines such as tumor necrosis factor (TNF) are important in the host response to Mycobacterium tuberculosis. TNF is involved in both granuloma formation and has direct anti-mycobacterial activity. This study investigated the secretion of interleukin (IL)-8 following phagocytosis of M. tuberculosis by a human monocytic cell line and by a more phenotypically mature macrophage-like cell line. M. tuberculosis is shown to be a more potent inducer of IL-8 but not of TNF than bacterial lipopolysaccharide in vitro in both cell types. IL-8 production is partly a consequence of accumulation of mRNA coding for this cytokine. Secretion of IL-8 is not a simple consequence of the phagocytic process but due to the specific interaction M. tuberculosis and the monocyte. IL-8 production was independent of TNF and of virulence of the strain of M. tuberculosis. IL-8 secretion following phagocytosis of M. tuberculosis suggests that this cytokine may be involved in granuloma formation in vivo, possibly acting, in part, as a T cell chemoattractant.
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PMID:Secretion of interleukin-8 following phagocytosis of Mycobacterium tuberculosis by human monocyte cell lines. 160 Oct 32

Ethanol intoxication has been associated with bacterial pneumonia and tuberculosis. More recently, ethanol was shown to impair the capacity of pulmonary macrophages to produce superoxide anion and tumor necrosis factor (TNF). Furthermore, exposure to ethanol compromises macrophage's ability to respond to stimulation with TNF and granulocyte-macrophage colony-stimulating factor (GM-CSF), and kill an intracellular pathogen, Mycobacterium avium. Based on these previous findings, we examined whether exposure to ethanol affects superoxide anion production, synthesis of cytokines, and expression of membrane receptors to TNF on human monocyte-derived macrophages. Brief exposure to 10 or 50 micrograms/dl of ethanol significantly reduced the macrophage's response to a subsequent stimulus with phorbol ester (phorbol-12-myristate-13-acetate, PMA), and this unresponsive state lasts for approximately 6 h following removal of ethanol. When macrophages were then treated with lipopolysaccharide (LPS) in the presence of ethanol, high concentrations of TNF and GM-CSF were produced, but subsequent stimulation with LPS (second stimulus) was associated with significant impairment on synthesis and release of both TNF and GM-CSF. In addition, although ethanol had no effect on TNF binding to resting macrophages and to macrophages infected with M. avium, ethanol significantly reduced the expression of TNF receptors on interferon-gamma-stimulated macrophages. The ethanol-induced inhibition of macrophage function suggests potential mechanisms for suppression of the host's immune response and consequently increased susceptibility for infectious diseases.
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PMID:Ethanol affects release of TNF and GM-CSF and membrane expression of TNF receptors by human macrophages. 166 88

This study shows that normal human large granular lymphocytes (LGL) secrete tumor necrosis factor (TNF) in response to Mycobacterium avium-intracellulare complex (MAI). Percoll density gradient fractionation of peripheral mononuclear cells showed TNF activity in the fractions corresponding to LGL and not T cells, even when 5% monocytes were added to the T lymphocytes for accessory function. TNF release was not abrogated by treatment of the crude LGL preparations with anti-Leu M3, -CD4, and -CD8 antibodies (Ab) plus complement (C), but was abrogated by anti-CD16 and -CD2 Ab, as expected. Interestingly, anti-HLA-DR monoclonal antibody (mAb) treatment significantly diminished TNF activity from LGL, but maintained natural killer (NK) cell function unmodified as opposed to CD2+ and CD16+ cell depletion. Panning studies demonstrated that TNF secretion upon MAI stimulation resided only in the HLA-DR+ LGL and not the DR- LGL population. These results indicate that normal fresh HLA-DR+ LGL, as well as monocytes, are also responsible for rapid TNF secretion during early MAI infection. These DR+ cells appear to be distinct from those expressing NK function.
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PMID:Involvement of HLA-DR+ large granular lymphocytes in the induction of tumor necrosis factor by Mycobacterium avium-intracellulare complex. 168 7

Acquired cell-mediated immunity to intracellular parasites like mycobacteria is dependent on antigen-specific T lymphocytes. We have recently found that mycobacteria not only induce helper T cells but also cytotoxic CD4+ and/or CD8+ T cells as well as nonspecific killer cells that lyse human macrophages in vitro. In addition, we have described that the recombinant heat-shock protein (hsp) 65 of Mycobacterium bovis BCG/M, tuberculosis is an important target antigen for CD4+CD8- cytotoxic T cells. We have now further investigated the cytotoxic effector cells that are induced by the hsp65 of BCG. Purified protein derivative of tuberculin (PPD)- or hsp65-specific cytotoxic T cells specifically lysed PPD, hsp65 of BCG and hsp65 of M. leprae-pulsed macrophages in an HLA-DR-restricted manner. Nonpulsed macrophages were lysed to a much lower but still significant extent. hsp65-induced effector cells expressed CD3, CD5, CD4, CD8 and CD56 markers. Depletion experiments showed that the antigen-specific HLA-DR-restricted killer cell was of the CD5+CD4+CD8-CD56- phenotype. Experiments using N-terminal truncated hsp65 fusion (cro-lacZ) proteins suggested that the N-terminal 65 amino acid residues of the 540 amino acid molecule are critical for the expression of the cytotoxic target epitope(s) in two individuals tested. In addition to inducing antigen-specific cytotoxic effector cells, the hsp65 also triggered nonspecific nonrestricted effector cells with lytic activity against nonpulsed autologous or allogeneic macrophages as well as K-562 and Daudi tumor cells. hsp65-stimulated effector cells produced both interferon and tumor necrosis factor-alpha. An important finding was that hsp65-stimulated effector cells strongly inhibited colony-forming unit formation from live BCG-infected autologous macrophages.
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PMID:Induction of antigen-specific CD4+ HLA-DR-restricted cytotoxic T lymphocytes as well as nonspecific nonrestricted killer cells by the recombinant mycobacterial 65-kDa heat-shock protein. 169 Jan 36


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