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- Berglin, Ewa H., MD, PhD, 1955-, et al.
(författare)
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Potentiation by sulfide of hydrogen peroxide-induced killing of Escherichia coli
- 1985
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Ingår i: Infection and Immunity. - : American Society for Microbiology. - 0019-9567 .- 1098-5522. ; 49:3, s. 538-543
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Tidskriftsartikel (refereegranskat)abstract
- L-Cysteine potentiates 100-fold the hydrogen peroxide-induced killing of a growing culture of Escherichia coli K-12 (Berglin et al., J. Bacteriol. 152:81-88). In the present study it is shown that hydrogen sulfide is formed from L-cysteine and that sodium sulfide could substitute for L-cysteine in the potentiation of hydrogen peroxide-induced killing of E. coli K-12. Addition of an amino acid, L-leucine, L-valine, or L-alanine, to an L-cysteine-containing medium with a growing culture of E. coli K-12 inhibited hydrogen sulfide formation and the potentiation of hydrogen peroxide-induced killing. These amino acids did not inhibit hydrogen sulfide formation from L-cysteine by a cell extract, and they did not inhibit the potentiation by sulfide of hydrogen peroxide-induced killing. This indicated that the amino acids protected the culture from L-cysteine-potentiated, hydrogen peroxide-induced killing by inhibiting the transport of L-cysteine into the cell. The potentiation by sodium sulfide of hydrogen peroxide-induced killing was abolished by the metal ion chelator 2,2'-bipyridyl. This indicated that metal ions, in addition to sulfide, were involved in the killing. Toxic effects of hydrogen peroxide are often presumed to be mediated by hydroxyl radicals formed in iron-catalyzed reactions. It was demonstrated that iron sulfide was more efficient than ferrous iron in catalyzing the formation of hydroxyl radicals from hydrogen peroxide. It was suggested that hydrogen sulfide formed in polymicrobial infections may play an important role in the host defense by potentiating the antimicrobial effect of hydrogen peroxide produced by phagocytic cells.
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| 2. |
- Holmgren, J, et al.
(författare)
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Enterotoxigenic Escherichia coli diarrhea in an endemic area prepares the intestine for an anamnestic immunoglobulin A antitoxin response to oral cholera B subunit vaccination.
- 1988
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Ingår i: Infection and Immunity. - 0019-9567 .- 1098-5522. ; 56:1, s. 230-3
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Tidskriftsartikel (refereegranskat)abstract
- We examined whether infection with enterotoxigenic Escherichia coli (ETEC) producing the heat-labile enterotoxin (LT) can prime the gut immune system to respond more efficiently to the immunologically related cholera B subunit component of a recently developed oral B subunit-whole-cell cholera vaccine (B-WCV). Nine Bangladeshi adults who had been hospitalized for watery diarrhea caused by LT-producing ETEC were given a single oral immunization with B-WCV on day 28 after hospital admission. The vaccine preparation used was adjusted to contain a lower-than-usual dose of B subunit, which had been found in previous studies to elicit a significant gut mucosal immunoglobulin A antitoxin response mainly in individuals with previous toxin-specific priming of their gut immune system. For comparison, nine patients convalescing from severe cholera disease and eight healthy subjects with no recent history of either cholera or ETEC infection were given the same oral vaccination with B-WCV. Vaccination in the ETEC convalescents induced an immunoglobulin A antitoxin response in intestinal lavage fluid which was comparable with that in the vaccinated cholera convalescents and superior to that in the vaccinated, previously uninfected controls. By contrast, only the cholera patients responded with anamnestic-type anti-cholera lipopolysaccharide antibody titer rises in the intestine after vaccination. These data support the specificity of the anamnestic anti-cholera toxin response in the ETEC patients after vaccination with cholera B-WCV.
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