Cross-protection between distantly related spotted fever group rickettsiae

Hui Min Feng, David H. Walker

Research output: Contribution to journalArticlepeer-review

23 Scopus citations


Two excellent C3H/HeN mouse models of spotted fever rickettsioses caused by the distantly related organisms, Rickettsia conorii and Rickettsia australis, were utilized to evaluate the possibility of the stimulation of broad cross-protective immunity. Sublethal infection stimulated complete immunity, that is absence of disease, after challenge with a dose of the heterologous Rickettsia that uniformly killed naïve mice. In contrast, heterologous immune sera did not protect mice against a lethal dose (two LD50) of rickettsiae in the mouse toxicity neutralization assay, the standard method for evaluation of rickettsial vaccine potency. These observations suggest that development of a broadly protective vaccine against spotted fever group (SFG) rickettsiae is feasible, and the results indicate that mouse toxicity neutralization is an inappropriate method for evaluation of candidate vaccines.

Original languageEnglish (US)
Pages (from-to)3901-3905
Number of pages5
Issue number25-26
StatePublished - 2003


  • Mouse models
  • Protective immunity
  • Rickettsia australis
  • Rickettsia conorii
  • Toxicity neutralization

ASJC Scopus subject areas

  • Molecular Medicine
  • General Immunology and Microbiology
  • General Veterinary
  • Public Health, Environmental and Occupational Health
  • Infectious Diseases


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