Phase variation of the lpf operon is a mechanism to evade cross-immunity between Salmonella serotypes

Tracy L. Norris, Andreas J Baumler

Research output: Contribution to journalArticlepeer-review

35 Scopus citations

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 languageEnglish (US)
Pages (from-to)13393-13398
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Volume96
Issue number23
DOIs
StatePublished - Nov 9 1999
Externally publishedYes

ASJC Scopus subject areas

  • Genetics
  • General

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