Immune response in mice and cattle after immunization with a Boophilus microplus DNA vaccine containing bm86 gene

Plasmid pBMC2 encoding antigen Bm86 from a Colombian strain of cattle tick Boophilus microplus, was used for DNA-mediated immunization of BALB/c mice, employing doses of 10 and 50 μg, delivered by intradermic and intramuscular routes. Anti-Bm86 antibody levels were significantly higher compared to control mice treated with PBS. In the evaluation of immunoglobulin isotypes, significant levels of IgG2a and IgG2b were observed in mice immunized with 50 μg of pBMC2. Measurement of interleukine (IL) levels (IL-4, IL-5, IL-12(p40)) and interferon-γ (IFN-γ) in the sera of mice immunized with pBMC2 indicated high levels of IL-4 and IL-5, although there were also significant levels of IFN-γ. Mice immunized with pBMC2 showed antigen-specific stimulation of splenocytes according to the incorporation of bromodeoxyuridine and IFN-γ secretion. In all trials, mice injected intramuscularly with 50 μg of pBMC2 presented the highest immune response. Moreover, cattle immunized with this DNA vaccine showed antibody production significantly different to the negative control. In conclusion, these results suggest the potential of DNA immunization with pBMC2 to induce humoral and cellular immune responses against B. microplus.