Bactericidal Activity of Serum By Brucella Abortus RB51 Outer Membrane Protein’s Combined By Brucella Abortus S99 Lipopolysaccharide Induction

Brucellosis vaccines are designed to induce the cellular immunity. An effective brucellosis vaccine is one that could induce both cellular and humoral immunity. Serum Bactericidal Assay(SBA) is an important method for the determination of vaccine humoral immunity. This study is the first to observe humoral immunity in brucellosis by SBA. Extracted B.abortus LPS and OMP’s were injected to rabbits. Group1 injected by 25µg of LPS, Group2 injected by 50µg of OMP ‘s and Group3 injected by 1ml of combined vaccine, 3 times every 2 weeks. The Groups were challenged with B.abortus 544 in the second injection. Sera were separated 2 weeks after the last injection. SBA was performed, each well was streak cultured into a plate of Brucella Agar. Colony count was done for each plate. Results have shown, the third injection of the combined vaccine, had the highest titer of 1/64, and the efficacy of the vaccine was %87.71.