Development and Efficacy Evaluation of Multivalent DNA Vaccine against Brucellosis.

Attenuated live Brucella strains are currently used in vaccines against brucellosis, causing serious side effects in animals and being hardly suitable for human vaccination. To develop a safer vaccine against brucellosis, plasmid DNA was constructed to express six Brucella proteins in mammalian cells. Linear polyethylenimine was used to increase the efficiency of DNA delivery into cells. Data on optimization of the conditions for the formation of DNA-polyethylenimine complexes were described. A single intramuscular or subcutaneous injection of plasmid DNA complexes with polyethylenimine at a low dose (20 μg/mouse) was shown to exert a reliable protective effect against subsequent challenge with a test Brucella strain.