Journal article
Response of Leishmania chagasi promastigotes to oxidant stress
Infection and immunity, Vol.62(11), pp.5133-5141
11/1994
DOI: 10.1128/IAI.62.11.5133-5141.1994
PMCID: PMC303235
PMID: 7927797
Abstract
At the onset of infection, Leishmania promastigotes are phagocytized by mammalian macrophages. They must survive despite exposure to toxic oxidants such as hydrogen peroxide (H2O2) and superoxide (.O2-) generated during phagocytosis. We investigated the effects of these oxidants on Leishmania chagasi promastigotes and promastigote mechanisms for oxidant resistance. According to spin trapping and electron paramagnetic resonance spectrometry, .O2- could be generated by exposure of promastigotes to the redox-cycling compound menadione. Incubation in either menadione or H2O2 caused a concentration-dependent loss of promastigote viability. However, incubation in sublethal concentrations of H2O2 or menadione caused a stress response in promastigotes. This oxidant-induced response was associated with an increase in the amount of heat shock protein hsp70. Induction of a stress response by exposure of promastigotes either to heat shock or to sublethal oxidants (H2O2 or menadione) caused promastigotes to become more resistant to H2O2 toxicity. Sublethal menadione also caused promastigotes to become more virulent in a BALB/c mouse model of leishmaniasis. We previously correlated H2O2 cytotoxicity for promastigotes with the formation of hydroxyl radical (.OH) from H2O2. However, according to electron paramagnetic resonance spectrometry, the increase in H2O2 resistance after exposure to sublethal oxidants was not associated with diminished generation (i.e., scavenging) of .OH. These data suggest that there is a cross-protective stress response that occurs after exposure of L. chagasi promastigotes to heat shock or to sublethal H2O2 or .O2-, exposures that also occur during natural infection. This response results in increased resistance to H2O2 toxicity and increased virulence for a mammalian host.
Details
- Title: Subtitle
- Response of Leishmania chagasi promastigotes to oxidant stress
- Creators
- M E Wilson - Veterans Affairs Medical Center, Iowa City, Iowa 52242K A AndersenB E Britigan
- Resource Type
- Journal article
- Publication Details
- Infection and immunity, Vol.62(11), pp.5133-5141
- Publisher
- United States
- DOI
- 10.1128/IAI.62.11.5133-5141.1994
- PMID
- 7927797
- PMCID
- PMC303235
- ISSN
- 0019-9567
- eISSN
- 1098-5522
- Grant note
- AI28412 / NIAID NIH HHS AI30126 / NIAID NIH HHS AI32135 / NIAID NIH HHS
- Language
- English
- Date published
- 11/1994
- Academic Unit
- Microbiology and Immunology; International Programs; Epidemiology; Internal Medicine
- Record Identifier
- 9984001159802771
Metrics
16 Record Views