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

A novel class of catalase, which differs from the previously described M- and T-catalases of mycobacteria, was detected in strains of Mycobacterium avium and M. intracellulare. Designated A-catalase, this enzyme resisted inactivation at 68 degrees C, was inactivated by 3-amino-1,2,4-triazole (aminotriazole), and exhibited no peroxidase activity. All of these properties distinguished the enzyme from T-catalase. The A-catalase exhibited a Km of 70 mM H2O2, which is between the upper and lower extremes of the ranges reported for T- and M-catalases, respectively. The A-catalase appeared to be more hydrophobic than M-catalase and did not react with antiserum to a representative sample of this class. The banding patterns of T- and M-catalases seen by polyacrylamide gel electrophoresis (PAGE) were essentially unaffected by the incorporation of sodium dodecyl sulfate (SDS) into the PAGE system, whereas the single band of A-catalase seen by PAGE without SDS resolved into as many as five bands in the presence of SDS; these bands were all of slower mobility than the original band. The banding pattern seen with SDS appeared to be related more to counterion charge effects than to molecular size increases that could be attributed to SDS complexed to the protein. It remains to be determined whether the multiple A-catalase bands reflect different proteins or different SDS micellar complexes of a single protein.
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PMID:Detection of a novel catalase in extracts of Mycobacterium avium and Mycobacterium intracellulare. 334 77

The five mycobacteria Mycobacterium lepraemurium, M. leprae, M. bovis BCG, M. smegmatis, and M. intracellulare were studied. Catalase and peroxidase activities were demonstrated in polyacrylamide and crossed immunoelectrophoresis gels for M. lepraemurium, M. intracellulare, and BCG, but not for M. leprae. Peroxidase and catalase activities were associated with the same precipitate line in crossed immunoelectrophoresis for M. lepraemurium, M. intracellulare, and BCG, showing that in these mycobacteria the two enzyme activities resided in the same molecule. M. smegmatis peroxidase and catalase activities were closely associated on polyacrylamide gel electrophoresis, but on the crossed immunoelectrophoresis catalase and peroxidase activities were associated with two different precipitate lines. Catalases without peroxidase activity were demonstrated in crossed immunoelectrophoresis and polyacrylamide gel electrophoresis in M. intracellulare and M. smegmatis. The catalase without peroxidase activity in M. intracellulare was heat resistant and therefore classified as an m-catalase. In M. smegmatis the catalase without peroxidase activity was only partially heat resistant. All of the catalases with peroxidase activity were heat-sensitive t-catalases. Superoxide dismutase activity in the crossed immunoelectrophoresis was associated with the M. leprae antigen no. 4 and with cross-reacting antigens in the other mycobacteria studied. Several superoxide dismutases were demonstrated in Mycobacterium duvalii. They were antigenically different from the other superoxide dismutases in this study, as shown by lack of reactivity with a monospecific antibody to M. lepraemurium superoxide dismutase. Molecular weights were estimated for all the enzymes in this study by sodium dodecyl sulfate-polyacrylamide gels.
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PMID:Catalases, peroxidases, and superoxide dismutases in Mycobacterium leprae and other mycobacteria studied by crossed immunoelectrophoresis and polyacrylamide gel electrophoresis. 353 45

To investigate the immune defect in lepromatous leprosy we studied immune cell phenotypes, lymphocyte activation states, and interleukin-2 (IL-2) production in naturally occurring leprosy skin lesions. Mouse hybridoma monoclonal antibodies reacting with the IL-2 receptor (anti-Tac), unbound IL-2 (DMS-1), antigen-presenting Langerhans' cells (OKT6) and the OKT4-Leu3 and OKT8 T-lymphocyte subpopulations were used with indirect horseradish peroxidase and alkaline phosphatase techniques on frozen biopsy sections. The percentage of Tac+ lymphocytes and the number of OKT6+ cells in the epidermis and dermal granuloma were significantly correlated in naturally occurring lesions (correlation coefficient 0.79) and were higher in tuberculoid than in lepromatous lesions. Leu3 antigen was expressed by 70-90% of Tac+ cells in tuberculoid lesions. Although the percentage of cells producing IL-2 was low in lesions of both lepromatous and tuberculoid patients, it was about 15 times greater in tuberculoid than in lepromatous lesions (0.032 +/- 0.037 tuberculoid vs 0.0019 +/- 0.023 lepromatous). There was an association between the number of OKT6+ cells and the percentage of IL-2-producing cells, but the association was weaker than that of OKT6+ cells and the percentage of IL-2 receptor-bearing cells (r = 0.2), implying that IL-2 production is not an intervening variable in the latter association. The absolute number of OKT4-Leu3+ lymphocytes was significantly different in different clinical leprosy groups and was positively correlated with host resistance (mean OKT4-Leu3+ cells/mm2 in 6 micron sections; 1412 +/- 288 tuberculoid, 400 +/- 93 borderline lepromatous, 200 +/- 100 polar lepromatous; r = 0.95). Absolute numbers of OKT8+ cells/mm2 in lesions were not significantly different. We conclude that there is a relative paucity of OKT4-Leu3+ cells as well as IL-2-producing cells at the local level in lepromatous leprosy lesions. Possible functional relationships between these findings and the failure of macrophage activation and destruction of Mycobacterium leprae in lepromatous leprosy are discussed.
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PMID:In vivo responses to Mycobacterium leprae: antigen presentation, interleukin-2 production, and immune cell phenotypes in naturally occurring leprosy lesions. 390 Feb 45

Mycobacterium leprae are killed by myeloperoxidase (or eosinophil peroxidase), H2O2, and a halide, thus suggesting a mechanism for their destruction by peroxidase-containing phagocytes.
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PMID:Toxic effect of the peroxidase-hydrogen peroxide-halide antimicrobial system on Mycobacterium leprae. 632 50

Forty-six skin biopsies from lepromatous leprosy patients were examined for immunoglobulin and complement deposits as well as mycobacterial antigens. Rabbit anti-human immunoglobulin, rabbit anti-human C3, and rabbit anti-Mycobacterium bovis (BCG) were used as the primary antigen-detecting antibodies in a peroxidase antiperoxidase technique. Of the 26 biopsies from active erythema nodosum leprosum lesions, 6 were positive for immunoglobulin or complement deposits. These deposits were found in the dermoepidermal junction, within the foamy cells, and, in one patient, around a blood vessel. Five of twenty patients with lepromatous leprosy without erythema nodosum leprosum showed similar deposits in the dermoepidermal junction and within foamy cells. None of these patients had these deposits around blood vessels. Mycobacterial antigens were seen in all biopsies studied. The presence of acute inflammatory infiltrates did not correlate with the presence or absence of immunoglobulin or complement deposits. It is felt that immunoglobulin or complement deposits are not a constant feature of early erythema nodosum leprosum lesions and that these deposits may be secondary rather than primary in these lesions.
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PMID:Immunohistological studies of skin biopsies from patients with lepromatous leprosy. 633 25

An indirect immunoperoxidase procedure for the diagnosis of paratuberculosis was described. Formalin-fixed ileocecal tissue containing large numbers of Mycobacterium paratuberculosis organisms was used as the source of antigen. Goat anti-bovine immunoglobulin G labeled with peroxidase was used as the conjugate in the test system. The method is relatively simple to do and may prove to be valuable as a routine screening test.
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PMID:Indirect immunoperoxidase test for the diagnosis of paratuberculosis. 635 83

Peripheral nerve biopsies from patients with leprosy were stained with anti-Mycobacterium bovis (BCG) in a peroxidase-antiperoxidase (PAP) system to demonstrate intraneural mycobacterial antigens. Most M. leprae antigens have been shown to cross-react with BCG. Of the 30 biopsies from borderline tuberculoid (BT) patients 18 had acid-fast bacilli while 26 of them had demonstrable mycobacterial antigens in their nerves. All borderline lepromatous (BL) and lepromatous leprosy (LL) nerve biopsies had both M. leprae and mycobacterial antigens within them. Most of the antigens in the BT patients were seen to be extracellular. In BL and LL patients antigens were seen both extracellularly and intracellularly in Schwann cells and infiltrating macrophages. Mycobacterial antigens in BT nerves were always seen to be surrounded by a mononuclear cell reaction while in the BL and LL patients antigens could be seen with minimal cellular infiltrate and the neural architecture was more or less preserved. While bacilli could not be seen in BT patients who had been released from treatment for more than 4 years, mycobacterial antigens could still be seen in some patients who had been released from treatment for up to 5 years. Patients with no skin lesions but with large, painful, or tender nerves were found to have intraneural inflammation surrounding mycobacterial antigens, while those with a similar clinical picture but without tender or painful nerves showed no marked inflammation within their nerves despite the presence of mycobacterial antigens. From these findings it was concluded that immunologically mediated inflammatory response toward intraneurally located M. leprae antigens in conjunction with other host factors may be necessary for nerve damage in the BT leprosy patients. In the BL and LL patients the mechanisms of nerve damage are still unknown with certainty but local effects and immune-complex damage secondary to abundant M. leprae antigens are worth exploring. The use of immunohistological techniques should offer a new approach in the study of the immunopathology of leprosy.
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PMID:Demonstration of mycobacterial antigens in nerve biopsies from leprosy patients using peroxidase-antiperoxidase immunoenzyme technique. 641 26

A study was made of mycobacterial-induced granulomas in guinea-pig lymph nodes. Live BCG (Pasteur) induced a granuloma containing epithelioid cells while Cobalt irradiated Mycobacterium leprae induced a granuloma comprised of phagocytic macrophages. The granulomas were quantitated by measurement of lymph node weight and the areas of infiltration in histological sections. The time course of granuloma formation induced by Co-irradiated M. leprae was veary different from the time course of the granuloma formation induced by BCG. Collagen synthesis assessed by incorporation of 14C-proline into collagenase sensitive protein was greater in lymph nodes draining the site of injection of Co-irradiated BCG than those draining the site of injection of Co-irradiated M. leprae during the first 10 weeks. Collagen synthesis was delayed in the nodes from animals injected with live BCG for at least 10 weeks. Single cell suspensions of draining lymph nodes containing granulomas consisted of lymphocytes and large cells (epithelioid cells and macrophages). A high proportion of the large cells were found to be non-adherent in the live BCG-induced epithelioid cell granuloma. In contrast, M. leprae-induced granulomas contained a high percentage of adherent large cells. In both the granulomas, the majority of large cells were esterase positive and showed the presence of fibronectin. Most of the large cells in the granulomas did not carry receptors for the Fc component of IgG or the C3 component of complement and did not exhibit peroxidase activity.
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PMID:Comparison of mycobacterial granulomas in guinea-pig lymph nodes. 675 60

An enzyme-linked immunosorbent assay (ELISA) was developed, using protein A labeled with horseradish peroxidase for detecting antibodies in tuberculous exotic mammals (llamas, rhinoceroses, elephants). The modified ELISA provides a rapid procedure for screening several animal species simultaneously for tuberculosis without the production of specific anti-species conjugates. Heat-killed cells of Mycobacterium bovis and M avium and purifed protein-derivative tuberculin of M bovis were used as antigens for ELISA.
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PMID:Enzyme-linked protein A: an enzyme-linked immunosorbent assay reagent for detecting antibodies in tuberculous exotic animals. 677 51

At low pH and with continuous low concentrations of hydrogen peroxide generated in situ, catalase was able to replace peroxidase in the peroxidase/hydrogen peroxide/iodide microbicidal system. The system was effective against Escherichia coli and Mycobacterium tuberculosis. Iodide could not be replaced by chloride. The system was effective in lactate buffer, but not in citrate/phosphate buffer. Strains of M. tuberculosis with high and low virulence were equally susceptible. The observations are discussed in the context of an involvement of host-cell catalase in a possible intracellular killing mechanism against M. tuberculosis.
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PMID:The susceptibility of strains of Mycobacterium tuberculosis to catalase-mediated peroxidative killing. 679 Jun 65


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