Abstract

Several live vaccines have been introduced so far to protect brucellosis but they have not been adopted broadly or their use has been discontinued for a variety of reasons. Immunity against facultative intracellular bacterial pathogen depends on acquired cell mediated immunity, distinguished by the activation of T-lymphocytes and subsequent activation of macrophages for increased killing of such intracellular pathogens. Three minor Outer membrane proteins (Omp19, Omp16.5 and Omp10) are expressed in all six Brucellaspecies and all of their biovars. We investigated the capacity of Brucella abortus, outer membrane protein 19 (Omp19) to elicit splenic lymphocytes stimulation response. We assessed the use of this protein as vaccine against Brucella in BALB/c mice. B. abortus Omp19 was cloned in pET28a(+) vector and Competent E. coli BL21(DE3) was transformed with the corresponding constructs, and rOmp19 was successfully expressed after induction with 1 mM IPTG. The expressed protein was purified using nickel affinity chromatography and confirmed by western blot analysis using polyclonal rabbit antibodies. BALB/c mice immunization with rOmp19 conferred significant protection against B. abortus infection. The potential usefulness of this antigen of B. abortus would be of great importance in eradication of brucellosis in future.

Key words: Brucella abortus, recombinant outer membrane protein 19 (rOmp19), Lymphocyte proliferation.