Major species-specific antibody epitopes of the Ehrlichia chaffeensis p120 and E. canis p140 orthologs in surface-exposed tandem repeat regions

Tian Luo, Xiaofeng Zhang, Jere McBride

Research output: Contribution to journalArticle

30 Scopus citations


Ehrlichia chaffeensis and E. canis have a small subset of tandem repeat (TR)-containing protein orthologs, including p120/p140, which elicit strong antibody responses. The TR regions of these protein orthologs are immunoreactive, but the molecular characteristics of the p120/p140 epitopes have not been determined. In this study, the immunodeterminants of the E. chaffeensis p120 and E. canis p140 were identified and molecularly defined. Major antibody epitope-containing regions of both p120 and p140 were localized to the TR regions, which reacted strongly by Western immunoblotting with antibodies in sera from E. chaffeensis-infected dogs or patients and E. canis-infected dogs, respectively. Single continuous species-specific major epitopes within the E. chaffeensis p120 and E. canis p140 TRs were mapped to homologous surface-exposed glutamate/aspartaterich regions (19 to 22 amino acids). In addition, minor cross-reactive epitopes were localized to homologous Nand C-terminal regions of p120 and p140. Furthermore, although the native and recombinant p120 and p140 proteins exhibited higher-than-predicted molecular masses, posttranslational modifications were not present on abnormally migrating p120 and p140 TR recombinant proteins as determined by matrix-assisted laser desorption ionization-time of flight mass spectrometry.

Original languageEnglish (US)
Pages (from-to)982-990
Number of pages9
JournalClinical and Vaccine Immunology
Issue number7
StatePublished - Jul 2009


ASJC Scopus subject areas

  • Clinical Biochemistry
  • Immunology
  • Immunology and Allergy
  • Microbiology (medical)

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