DNAs from Brucella Strains Activate Efficiently Murine Immune System with Production of Cytokines, Reactive Oxygen and Nitrogen Species

Brucellosis is an infectious disease with high impact on innate immune responses which is induced partly by its DNA. In the present study the potential differences of wild type and patients isolates versus attenuated vaccine strains in terms of cytokines, ROS and NO induction on murine splenocytes and peritoneal macrophages were investigated. This panel varied in base composition and included DNA from B. abortus, B. melitensis, B.abortus strain S19 and melitensis strain Rev1, as attenuated live vaccine. Also we included Escherichia coli DNA, calf thymus DNA (a mammalian DNA), as controls. These DNA were evaluated for their ability to stimulate IL-12, TNF-α, IL-10, IFN-γ and ROS production from spleenocytes as well as NO production from peritoneal macrophages. Spleen cells were cultured in 24 well at a concentration of 106 cells/ ml with subsequent addition of 10 μg/ml of Brucella or Ecoli DNAs. These cultures were incubated at 37ºC with 5% CO2 for 5 days. Supernatants were harvested and cytokines, ROS and NOx were evaluated. It was observed that TNF-α was induced in days 1,3,5 by all Brucella strains DNAs and E. coli DNA, IL-10 only was induced in day 1, IFN-γ was induced only in day 5 and IL-12 not induced. ROS and NOx were produced by all strains; however, we observed higher production of NOx which were stimulated by DNA of B. melitensis.