In silico analysis of Brucella abortus Omp2b and in vitro expression of SOmp2b

PURPOSE: At present, there is no vaccine available for the prevention of human brucellosis. Brucella outer membrane protein 2b (Omp2b) is a 36 kD porin existed in common Brucella pathogens and it is considered as priority antigen for designing a new subunit vaccine. MATERIALS AND METHODS: In the current study, we aimed to predict and analyze the secondary and tertiary structures of the Brucella abortus Omp2b protein, and to predict T-cell and B-cell epitopes with the help of bioinformatics tools. Subsequently, cloning and expression of the short form of Omp2b (SOmp2b) was performed using pET28a expression vector and Escherichia coli BL21 host, respectively. The recombinant SOmp2b (rSOmp2b) was purified with Ni-NTA column. RESULTS: The recombinant protein was successfully expressed in E. coli host and purified under denaturation conditions. The yield of the purified rSOmp2b was estimated by Bradford method and found to be 220 microg/mL of the culture. CONCLUSION: Our results indicate that Omp2b protein has a potential to induce both B-cell- and T-cell-mediated immune responses and it can be evaluated as a new subunit vaccine candidate against brucellosis.

Identification of Brucella abortus using the sequencing of omp gene / 대한내과학회지

BACKGROUND: As the incidence of bovine brucellosis increases in Korea, the incidence of human brucellosis is also increasing since 2002. However, it is difficult to identify Brucella species by using the conventional methods. METHODS: Three strains of gram-negative coccobacilli were isolated from blood specimens of three patients with prolonged fever, which were not identified by using the conventional methods. After extracting total DNA from these isolates, PCR amplification of 16S rRNA and omp2 genes was performed. These sequences secured by PCR assay were compared with known sequences by using GenBank BLAST. RESULTS: DNA sequences were obtained from 3 isolates by using PCR amplification of 16S rRNA. These sequences had more than 99.9% similarities with Brucella species by using GenBank BLAST. In the second place, after comparing DNA sequences secured by PCR amplification of omp2a and omp2b by using GenBank BLAST, these isolates were confirmed as B. abortus. CONCLUSIONS: DNA sequence analysis is a rapid and accurate method for identification of uncommon microorganisms, such as Brucella species.