title: Characterization of the major antigenic protein 2 of Ehrlichia canis and Ehrlichia chaffeensis and its application for serodiagnosis of ehrlichiosis.
abstract: Canine monocytic ehrlichiosis, caused by Ehrlichia canis or Ehrlichia chaffeensis, can result in clinical disease in naturally infected animals. Coinfections with these agents may be common in certain areas of endemicity. Currently, a species-specific method for serological diagnosis of monocytic ehrlichiosis is not available. Previously, we developed two indirect enzyme-linked immunosorbent assays (ELISAs) using the major antigenic protein 2 (MAP2) of E. chaffeensis and E. canis. In this study, we further characterized the conservation of MAP2 among various geographic isolates of each organism and determined if the recombinant MAP2 (rMAP2) of E. chaffeensis would cross-react with E. canis-infected dog sera. Genomic Southern blot analysis using digoxigenin-labeled species-specific probes suggested that map2 is a single-copy gene in both Ehrlichia species. Sequences of the single map2 genes of seven geographically different isolates of E. chaffeensis and five isolates of E. canis are highly conserved among the various isolates of each respective ehrlichial species. ELISA and Western blot analysis confirmed that the E. chaffeensis rMAP2 failed to serologically differentiate between E. canis and E. chaffeensis infections.
authors.affiliation: Department of Pathobiology, College of Veterinary Medicine, University of Florida, Gainesville, Florida 32610, USA.
authors.forename: Tamece T
authors.initials: TT
authors.lastname: Knowles
authors.forename: A Rick
authors.initials: AR
authors.lastname: Alleman
authors.forename: Heather L
authors.initials: HL
authors.lastname: Sorenson
authors.forename: David C
authors.initials: DC
authors.lastname: Marciano
authors.forename: Edward B
authors.initials: EB
authors.lastname: Breitschwerdt
authors.forename: Shimon
authors.initials: S
authors.lastname: Harrus
authors.forename: Anthony F
authors.initials: AF
authors.lastname: Barbet
authors.forename: Myriam
authors.initials: M
authors.lastname: Bélanger
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000942:Antigens, Bacterial / Q000235:genetics / Q000276:immunology*; D001131:Arkansas / Q000453:epidemiology; D001426:Bacterial Proteins; D003429:Cross Reactions; D004197:Disease Reservoirs; D004283:Dog Diseases / Q000175:diagnosis* / Q000276:immunology; D004285:Dogs; D041061:Ehrlichia canis / Q000235:genetics / Q000276:immunology*; D018469:Ehrlichia chaffeensis / Q000235:genetics / Q000276:immunology*; D016873:Ehrlichiosis / Q000175:diagnosis / Q000453:epidemiology / Q000276:immunology / Q000662:veterinary*; D004797:Enzyme-Linked Immunosorbent Assay; D005431:Florida / Q000453:epidemiology; D005798:Genes, Bacterial; D006801:Humans; D008969:Molecular Sequence Data; D009657:North Carolina / Q000453:epidemiology; D011993:Recombinant Fusion Proteins / Q000276:immunology; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D012698:Serologic Tests / Q000379:methods; D013045:Species Specificity; D014768:Virginia / Q000453:epidemiology
chemical_list: D000942:Antigens, Bacterial; D001426:Bacterial Proteins; C113541:MAP2 antigenic protein, Ehrlichia; D011993:Recombinant Fusion Proteins