Brucellosis is a zoonotic disease in human and animals. Brucella melitensis is one of the most pathogenic species of Brucella in goat and sheep. Omp31 is an outer membrane protein of Brucella that acts as an immunogenic protein. Cytokines are glycoproteins with low molecular weight that play the role of an immune adjuvant and regulate immune responses. Interleukin-2 is one of the most important cytokines, which are secreted by the white blood cells and involved in T cell immune responses. In the present study, a chimeric Omp31-Interleukin2 recombinant protein was generated by means of genetic engineering techniques. This chimeric coding sequence was amplified by using specific primers and using Splicing Overlap Extension (SOE) PCR technique. The fusion of the two mentioned proteins was accomplished using a rigid linker. The generated chimeric IL2-Omp31 fragment was TA cloned, and then subcloned into pEt22b vector as an expression vector. The chimeric protein was successfully expressed in E. coli BL21 (DE3) and confirmed by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and also Western-blotting analysis. Finally, in order to assess the antigenic features of the recombinant chimeric IL2-Opm31 protein, its secondary structure and antigenicity were predicted in silico.

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