A DNA Vaccine Encoding Lumazine Sythase from Brucella abortus Induces Protective Immunity in BALB/c Mice

C A, VELIKOVSKI; CASSATARO J,; GIAMBARTOLOMEI GH,; F G, GOLDBAUM; ESTEIN S,; BOWDEN RA,; BRUNO L,; CARLOS ALBERTO FOSSATI; SPITZ M,

JOURNAL OF INFECTIOUS DISEASES

UNIV CHICAGO PRESS

Año: 2002 vol. 182 p. 252 - 259

0022-1899

This study was conducted to evaluate the immunogenicity of the Brucella abortus lumazine synthase (BLS)gene cloned into the pcDNA3 plasmid, which is driven by the cytomegalovirus promoter. Injection of plasmidDNA carrying the BLS gene (pcDNA-BLS) into BALB/c mice elicited both humoral and cellular immuneresponses. Antibodies to the encoded BLS included immunoglobulin G1 (IgG1) IgG2a, IgG2b, IgG3, and IgMisotypes. Animals injected with pcDNA-BLS exhibited a dominance of IgG2a over IgG1. In addition, spleencells from vaccinated animals produced interleukin-2 and gamma interferon but not IL-10 or IL-4 after in vitrostimulation with recombinant BLS (rBLS), suggesting the induction of a Th1 response. Protection wasevaluated by comparing the levels of infection in the spleens of vaccinated mice challenged with B. abortus 544.Immunization with pcDNA-BLS- reduced the bacterial burden relative to those in the control groups. Miceimmunized with rBLS produced a significant humoral response but did not show a specific cellular responseor any protection from challenge. Altogether, these data suggest that pcDNA-BLS is a good immunogen for theproduction of humoral and cell-mediated responses in mice and is a candidate for use in future studies ofvaccination against brucellosi