Killing of Mycobacterium microti by immunologically activated macrophages

Walker, Linda L.; Lowrie, Douglas B.

doi:10.1038/293069a0

Cited by 139 publications

(68 citation statements)

References 14 publications

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“…8 depicts a proposed model for the role of Nramp in macrophage defense against microbial invasion. Following the phagocytosis of a parasite into the phagosome, the macrophage produces reactive oxygen and/or nitrogen intermediates that are toxic for the internalized bacteria (43,44 …”

mentioning

confidence: 99%

A yeast manganese transporter related to the macrophage protein involved in conferring resistance to mycobacteria.

Supek

Supeková²,

Nelson³

et al. 1996

Proc. Natl. Acad. Sci. U.S.A.

316

261

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A novel Saccharomyces cerevisiae mutant, unable to grow in the presence of 12.5 mM EGTA, was isolated by replica plating. The phenotype of the mutant is caused by a single amino acid change (Gly'49 to Arg) leu2, his3, ade2, trpl, ura3), leu2, his3, ade2, trpl, ura3), E20 (MA Ta, masi), and CRB1-5A (MATa, leu2, his3, his4-4Q1, trpl, ura3-52, HOLJ-1, masl-ts) were used. EGTA-sensitive mutants were generated by exposing yeast cells to ethyl methanesulfonate (EMS) as described (14) and replica plating on YPD plates (pH 6.0) containing 50 mM Mes and 12.5 mM EGTA. The mutants denoted as csp (chelator-sensitive phenotype) were back-crossed to the wild-type strain as described elsewhere (15)

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mentioning

confidence: 99%

A yeast manganese transporter related to the macrophage protein involved in conferring resistance to mycobacteria.

Supek

Supeková²,

Nelson³

et al. 1996

Proc. Natl. Acad. Sci. U.S.A.

316

261

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“…The most direct evidence implicating catalases as mycobacterial virulence factors is derived from studies demonstrating the protective effect of exogenous catalase. In these experiments, exogenous catalase protected against the killing of Mycobacterium microti by lymphokine-activated murine macrophages (18). More recent studies have shown, however, that the resistance of M. intracellulare strains to peroxide does not correlate with their catalase content and that the susceptibility of M. tuberculosis to killing by activated macrophages is not related to peroxide susceptibility (14).…”

mentioning

confidence: 85%

Nucleotide sequence of the Mycobacterium leprae katG region

et al. 1997

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Synthetic oligonucleotide primers based on the DNA sequence data of the Escherichia coli, Mycobacterium tuberculosis, and Mycobacterium intracellulare katG genes encoding the heme-containing enzyme catalaseperoxidase were used to amplify and analyze the Mycobacterium leprae katG region by PCR. A 1.6-kb DNA fragment, which hybridized to an M. tuberculosis katG probe, was obtained from an M. leprae DNA template. Southern hybridization analysis with a probe derived from the PCR-amplified fragment showed that the M. leprae chromosome contains only one copy of the putative katG sequence in a 3.4-kb EcoRI-BamHI DNA segment. Although the nucleotide sequence of the katG region of M. leprae was approximately 70% identical to that of the M. tuberculosis katG gene, no open reading frame encoding a catalase-peroxidase was detectable in the whole sequence. Moreover, two DNA deletions of approximately 100 and 110 bp were found in the M. leprae katG region, and they seemed to be present in all seven M. leprae isolates tested. These results strongly suggest that M. leprae lacks a functional katG gene and catalase-peroxidase activity.Two catalases have been extensively characterized in Escherichia coli. HPI (encoded by katG) is a prokaryotic broadspectrum bifunctional peroxidase-catalase inducible by hydrogen peroxide (7). The E. coli catalase HPII (encoded by katE) is a monofunctional enzyme that has sequence similarities to eukaryotic catalase (17). Biochemical and serological characterizations of mycobacterial lysates have also identified two mycobacterial catalases (20). The mycobacterial T-catalase, which has been identified in most mycobacterial species, has substrate specificities similar to those of the E. coli HPI peroxidase-catalases. The mycobacterial M-catalase is a monofunctional HPII-like catalase which has a limited distribution within the mycobacterial genus. A few species, notably those in the Mycobacterium terrae complex, produce only M-catalase. Mycobacterium tuberculosis and Mycobacterium bovis produce only T-catalase. Mycobacterium avium and Mycobacterium intracellulare produce both classes of catalase (8,9,19,21). Since mycobacteria proliferate inside macrophages, it has been speculated that catalases may protect acid-fast bacilli from the deleterious effects of peroxide and, therefore, may play a crucial role in the in vivo survival of mycobacteria. The virulence of two other intracellular pathogens, Nocardia asteroides and Leishmania donovani, has been related to their catalase content (2). Catalases probably enhance the pathogenicity of these microorganisms by metabolizing hydrogen peroxide, a toxic oxygen metabolite which is released by phagocytes in response to bacterial challenge. There is extensive evidence which suggests that peroxide and its associated toxic oxygen metabolites are responsible, in part, for the antimycobacterial activity of macrophages. The most direct evidence implicating catalases as mycobacterial virulence factors is derived from studies demonstrating the protective effect of exo...

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“…The biological utility of this phenomenon is not clear. However, delayed basophil infiltrates are required for immune rejection of some large multicellular parasites, 2 whereas monocyte/macrophage-rich responses are more appropriate to immune resistance to facultative intracellular microorganisms, such as mycobacteria (1,25,26). Therefore, the ability of specific and nonspecific factors in immune serum to modulate the basophil vs. monocyte/macrophage component of T cell-dependent tissue responses might have important biological consequences.…”

Section: Discussionmentioning

confidence: 99%

Suppression of T cell-mediated cutaneous basophil hypersensitivity by serum from guinea pigs immunized with mycobacterial adjuvant.

Mitchell¹,

Askenase²

1982

The Journal of Experimental Medicine

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Delayed-type hypersensitivity reactions are mediated by specifically sensitized T cells that recruit auxiliary effector cells via release of lymphokines (1). Classical tuberculin-type delayed hypersensitivity (DH)1 reactions are induced when an antigen is administered in an adjuvant consisting of a water-in-oil emulsion containing mycobacteria (complete Freund's adjuvant [CFA]) (2). However, reactions with a delayed time-course can also be elicited in guinea pigs immunized with protein antigens administered in saline or water-in-oil emulsion not containing mycobacteria. These reactions differ from DH by their lack of induration and their early disappearance after immunization and testing (3).These evanescent delayed reactions that occur in animals immunized without mycobacterial adjuvants contain masses of basophils and are called cutaneous basophil hypersensitivity (CBH), a term that allows differentiation from DH reactions that contain few basophils (4). CBH reactions are "carrier specific" and are mediated by sensitized T cells (5-8), but immune serum can also mediate cutaneous basophil responses (9, 10). These latter reactions are hapten specific and can be transferred with small amounts of guinea pig IgG1 antibody (11). Thus, both T and B cell-derived factors participate in the generation of delayed basophil-rich cutaneous hypersensitivity responses.The fact that T cells can mediate both DH and CBH suggests that the two reactions are due to separate T cell subsets or that a common T cell is responsible for both reactions but that the final resulting components of the response (such as basophil content) are subject to regulatory factors. This latter possibility is suggested by the fact that guinea pigs immunized with CFA and skin tested at 3-4 wk have classical DH reactions with few basophils present, but recipients of T cells from these animals have delayed skin test reactions containing large basophil infiltrates (7). Thus, animals immunized for basophil-poor classical tuberculin reactions have T cells that can mediate CBH. The CBH activity of these cells appears to be suppressed, and it has been proposed that transfer removes them from a suppressive influence, thus allowing *

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Killing of Mycobacterium microti by immunologically activated macrophages

Cited by 139 publications

References 14 publications

A yeast manganese transporter related to the macrophage protein involved in conferring resistance to mycobacteria.

A yeast manganese transporter related to the macrophage protein involved in conferring resistance to mycobacteria.

Nucleotide sequence of the Mycobacterium leprae katG region

Suppression of T cell-mediated cutaneous basophil hypersensitivity by serum from guinea pigs immunized with mycobacterial adjuvant.

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