Abstract
Conventional wisdom holds that phase variation is a mechanism for immune evasion. However, despite fimbrial phase variation, mice previously exposed to Salmonella typhimurium are protected against a subsequent challenge. We evaluated whether lpf phase variation instead may be a mechanism to evade cross-immunity between Salmonella serotypes. Mice were immunized orally with S. typhimurium aroA mutants either that expressed the lpf operon (phase-on variant) or in which the entire lpf operon had been removed by deletion. During a subsequent challenge with virulent Salmonella enteritidis a selection against lpf phase-on variants was observed in mice previously exposed to S. typhimurium long polar fimbriae. Vaccination with S. typhimurium did not confer protection against challenge with S. enteritidis, presumably because lpf phase-off variants were able to evade cross-immunity. We propose that lpf phase variation is a mechanism to evade cross-immunity between Salmonella serotypes, thereby allowing their coexistence in a host population.
Original language | English (US) |
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Pages (from-to) | 13393-13398 |
Number of pages | 6 |
Journal | Proceedings of the National Academy of Sciences of the United States of America |
Volume | 96 |
Issue number | 23 |
DOIs | |
State | Published - Nov 9 1999 |
Externally published | Yes |
ASJC Scopus subject areas
- Genetics
- General