Abstract
Brucella canis is pathogenic for dogs and humans. Serological diagnosis is a cost-effective approach for disease surveillance, but a major drawback of current serological tests is the cross-reactivity with other bacteria that results in false positive reactions, and development of indirect tests with improved sensitivity and specificity remain a priority. A western blotting assay was developed to define the serum antibody patterns associated to infection using a panel of positive and negative dog sera. B. canis positive sera recognized immunogenic bands ranging from 7 to 30 kDa that were then submitted to ESI–LC-MS/MS and analyzed by bioinformatics tools. A total of 398B. canis proteins were identified.. Bioinformatics tools identified 16 non cytoplasmic immunogenic proteins predicted as non-homologous with the most important Brucella cross-reactive bacteria and 9 B. canis proteins non-homologous to B. ovis ; among the latter, one resulted non-homologous to B. melitensis . The western blotting test developed was able to distinguish between infected and non-infected animals and may serve as confirmatory test for the serological diagnosis of B. canis . The mass spectrometry and in silico results lead to the identification of specific candidate antigens that pave the way for the development of more accurate indirect diagnostic tests.
Keywords: Bioinformatics, Brucella canis ; Western blotting; Mass spectrometry; Protein identifi-cation