Genetic manipulation of probiotic bacterium Lactococcus lactis to produce OMP10 protein of Brucella abortus

In all species of Brucella bacteria, the Omp10 gene sequence is conserved. The high antigenic property of this gene product stimulates the host's immune system. Using the probiotic Lactococcus lactis bacterium as a live carrier, in addition to being safe, is suitable for the production of recombinant proteins and gene transfer to eukaryotic cells. Omp10 is one of the surface lipoproteins in brucella’s outer membrane with high immunogenicity which has a substantial role in up-taking nutrition, signaling, adherence, and antibiotic resistance. This protein has antigenic properties and can play an adjuvant role when attached to other antigens. Therefore, the purpose of this research is to create the probiotic bacteria Lactococcus lactis to produce the Omp10 protein of Brucella abortus.

Brucella abortus Omp10 gene with Usp45 peptide signal was synthetically cloned in the pNZ8148 vector. The recombinant vector was first reproduction in Escherichia coli strain TOP10 and then purified by plasmid extraction kit. The concentration of extracted plasmid was measured by nanodrop. The recombinant pNZ8148-Usp45-Omp10 vector was then transformed into Lactococcus lactis bacteria through electroporation. Cloning and gene expression assessment and verification were done by SDS-PAGE, enzyme digestions, and RT-PCR techniques.

The results showed the successful expression of the target gene Omp10 in the Lactococcus lactis probiotic bacteria. The recombinant protein was well expressed in probiotic bacteria.

The present study showed that the Omp10 protein is expressed in the probiotic bacterium Lactococcus lactis transformed by electroporation with the recombinant pNZ8148-Usp45-Omp10 vector. Lactococcus lactis transformed in the present study can be suitable as an oral subunit vaccine to prevent brucellosis in future studies.