Serological potential of recombinant proteins Brucella Spp. in the diagnosis of cattle brucellosis
One of the main links in the system of measures to eliminate brucellosis is the timely and reliable identification of infected animals. In the serodiagnosis of this disease, reactions such as RBPT, CFT (RCFT) and AT are widely used. Recently, various variants of ELISA tests find their application. Both in traditional reactions and in ELISA, lipopolysaccharides of smooth strains of Brucella spp. act as the main antigen, which complicates the differentiating infected from vaccinated animals. In addition, these tests do not always give objective results due to the cross-reactions of Brucella with other gram-negative bacteria. In this regard, the results of studies devoted to the determination of the diagnostic value of the protein components of the pathogen deserve close attention. The diagnostic potential of Brucella recombinant outer membrane proteins (OMP19, OMP25, OMP31) and the periplasmic protein - superoxide dismutase (SOD) in indirect ELISA was studied. The research results showed that cows 10 months after revaccination with B. abortus 19 in 60% of cases gave positive reactions by RBPT and indirect ELISA based on Brucella OMPs, while antibodies in indirect ELISA/SOD were detected only in 4% of the population. About one third of the suckling calves kept on with their mothers revaccinated against brucellosis had specific antibodies to Brucella OMPs by 6 months of postnatal ontogenesis. The use of individual recombinant proteins in indirect ELISA reduced the sensitivity of the test in serological studies of mother cows and their suckling calves. In serum of seropositive cows from epizootic foci of brucellosis, antibodies to Brucella OMPs as well as SOD were detected in 96.7-100% of cases. Thus, the obtained results provide the basis for further research to determine the serological potential of SOD in the differentiation of Brucella-infected from vaccinated animals.