Recombinant Omp2b antigen-based ELISA is an efficient tool for specific serodiagnosis of animal brucellosis

Abstract

Control of brucellosis as a worldwide zoonotic disease is based on vaccination of animals and diagnosis of infected cases to be eradicated. Accurate and rapid detection of infected animals is of critical importance for preventing the spread of disease. Current detection of brucellosis is based on whole-cell antigens and investigating serum antibodies against Brucella lipopolysaccharide (LPS). The critical disadvantage is misdiagnosis of vaccinated animals as infected ones and also cross-reactions with other Gramnegative bacteria. Recombinant outer membrane protein 2b (Omp2b) of Brucella abortus was evaluated as a novel serodiagnostic target in comparison to conventional tests which are based on LPS. Recombinant Omp2b (rOmp2b) was expressed in Escherichia coli BL21 and purified by Ni 2+-based chromatography. rOmp2b was evaluated in an indirect enzyme-linked immunosorbent assay (ELISA) system for diagnosis of brucellosis, with sera from Brucella-infected mice along with negative sera and sera from mice which were inoculated with other Gram-negative species for assurance of specificity. Thereafter, cattle sera collected from different regions were assessed along with known negative and known positive serum samples. We found that Omp2b can discriminate between Brucella-infected animals and non-infected ones. Results for assessment of two hundred and fifty cattle sera by Omp2b-based indirect ELISA which were compared to Rose Bengal plate agglutination test (RBPT) and serum tube agglutination test (SAT) showed that our proposed procedure has the sensitivity of 88.5%, specificity of 100%, and accuracy of 90.8%. We suggest that recombinant Omp2b could be used as a protein antigen for diagnosis of brucellosis in domestic animals and can be evaluated for detection of human brucellosis.

A Multi-Epitope Fusion Protein-Based p-ELISA Method for Diagnosing Bovine and Goat Brucellosis

“…Animal experiments indicated that Omp31 can not only elicit a strong humoral immune response in mice, but also protects mice against Brucella infection ( 23 , 24 ). Omp2b is another important candidate for brucellosis diagnostics and vaccine research ( 25 , 26 ). The data in this paper proved that the shorter linear peptides contained in these Omps are also effective in detecting brucellosis-positive sera.…”

Specific Serodiagnosis of Animal Brucellosis Based on A Recombinant Multiepitope Protein Antigen

“…Following Brucella infection, treatment is di cult, so the emphasis is on preventing and controlling brucellosis. Currently, the most commonly used vaccines are conventional live attenuated strains of B. melitensis and B. abortion B19 [7]. However, these vaccines have some disadvantages, such as the possibility of miscarriage in pregnant animals [8].…”

“…However, serum diagnostic tests for smooth Brucella LPS as a diagnostic antigen cannot distinguish infections caused by cross-reactive species; examples are Yersinia enterocolitica O9, Vibriocholerae, Escherichia, and Salmonella, which often lead to false positives [13]. Many studies have shown that Brucella outer membrane proteins (OMPs), mainly OMP16, periplasmic protein 26 (BP26), OMP2b, and OMP31, have strong immunoreactivity and are suitable for the diagnosis of brucellosis as a substitute for LPS [7,[14][15][16]. False-positive results from cross-reactive antibodies can be reduced by using OMPs to replace previous diagnostic antigens.…”

Simultaneous Immunization with Omp25 and L7/L12 Provides Protection against Brucellosis in Mice

“…In addition, L7/L12 is a conserved protein which is found to be immunogenic and a stimulant of Th1 type CD4 + cellular response in mice [17], making both these antigens relevant as components for divalent vaccine formulation against brucellosis. Further, many protective antigens from Brucella have been classified as specific and novel diagnostic target as compared to LPS based conventional tests [29,30].…”