Brucellosis is a well-known infection in domestic animals which caused by Brucella bacterium. Due to serious economic and medical consequences of this disease, various efforts have been made to prevent the infection through the use of recombinant vaccines based on Brucella outer membrane protein (OMP) antigens. The objectives of the present study were cloning, sequencing and epitope prediction of Omp25 and BLS genes as two major Brucella melitensis antigens. The full-length open reading frame (ORF) of Omp25 and BLS genes were amplified and cloned into pTZ57R/T vector. Phylogenetic analysis of sequenced genes showed that both genes were nearly similar in different Brucella species. Several online prediction softwares were used to predict B and T-cells epitopes, secondary and tertiary structures, antigenicity ability and enzymatic degradation sites. Bioinformatic tools used in the current study were confirmed by the results of three different experimental epitope predictions. Bioinformatic analysis identified five and two B-cell and two and one T-cell epitopes for Omp25 and BLS antigens, respectively. Finally, according to the antigenicity ability and proteosomal recognition site common B and T-cell epitope was predicted for Omp25 (154-162 amino acids) and BLS (37-48 and 119-139 amino acids). Results of this study might be useful for recombinant vaccine development.

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