Nucleic acid vaccination of Brucella abortus ribosomal L7/L12 gene elicits immune response

Nucleic acid vaccines provide an exciting approach for antigen presentation to the immune system. As a test of this new methodology, the immune response to the in vivo-expressed Brucella abortus ribosomal L7/12 gene in the muscle cells of mice was examined. To accomplish this goal the eukaryotic expression systems pcDNA3 and p6 were used. Single intramuscular injection of the L7/L12 gene driven by the human cytomegalovirus (CMV) promoter (pcDNA3) ol bovine MHC I promoter (p6) resulted in intracellular expression of the B. abortus L7/L12 immunodominant protein encoded by this gene, This application facilitated directed antigen presentation to the immune system and established specific antibody and T-cell responses compared with vector only (pcDNA(3)) negative controls and B. abortus S19 injected positive controls, Although pcDNA(3)-encoded L7/L12 gene-inoculated mice possessed significant protection, p6-L7/L12 did not engender-significant protection against B. abortus S2308 infection compared to positive control mice. These data suggest a promising antigen-specific response, and L7/L12 nucleic acid vaccination may be an initial step in the development of genetically engineer ed candidate vaccines against brucellosis, This study for the first time focuses on DNA immunization of a gene from B. abortus. (C) 1997 Elsevier Science Ltd.