title: Molecular cloning and characterization of the 120-kilodalton protein gene of Ehrlichia canis and application of the recombinant 120-kilodalton protein for serodiagnosis of canine ehrlichiosis.
abstract: The 120-kDa outer membrane protein (p120) is a potential adhesin of Ehrlichia chaffeensis, and recombinant p120 is very useful for serodiagnosis of human monocytotropic ehrlichiosis. The analogous gene of p120 in Ehrlichia canis was cloned, sequenced, and expressed. Like the E. chaffeensis p120, the E. canis p120 contains tandem repeat units. However, neither the repeat number nor the amino acid sequences in the repeats are identical in the two Ehrlichia species. The repeat units are hydrophilic and by probability analysis are predicted to be surface exposed in both species. The repeat regions of the p120s of the two species have common amino acid sequences that are predicted to be surface exposed. The overall amino acid sequence of the E. canis p120 is 30% homologous to that of E. chaffeensis p120. Protein immunoblotting demonstrated that the recombinant E. canis p120 reacted with convalescent sera from dogs with canine ehrlichiosis. These results indicate that the recombinant p120 is a potential antigen for the serodiagnosis of canine ehrlichiosis.
authors.affiliation: Department of Pathology, WHO Collaborating Center for Tropical Diseases, University of Texas Medical Branch, Galveston, Texas 77555-0609, USA.
authors.forename: X J
authors.initials: XJ
authors.lastname: Yu
authors.forename: J W
authors.initials: JW
authors.lastname: McBride
authors.forename: C M
authors.initials: CM
authors.lastname: Diaz
authors.forename: D H
authors.initials: DH
authors.lastname: Walker
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000907:Antibodies, Bacterial / Q000097:blood*; D001425:Bacterial Outer Membrane Proteins / Q000235:genetics / Q000276:immunology; D001483:Base Sequence; D003001:Cloning, Molecular; D004283:Dog Diseases / Q000175:diagnosis*; D004285:Dogs; D004536:Ehrlichia / Q000235:genetics / Q000276:immunology*; D018469:Ehrlichia chaffeensis / Q000235:genetics; D016873:Ehrlichiosis / Q000175:diagnosis / Q000662:veterinary*; D005798:Genes, Bacterial; D008969:Molecular Sequence Data; D011994:Recombinant Proteins; D020449:Repetitive Sequences, Amino Acid; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D012698:Serologic Tests; D013045:Species Specificity
chemical_list: D000907:Antibodies, Bacterial; D001425:Bacterial Outer Membrane Proteins; D011994:Recombinant Proteins