Brucella Lumazine Sinthase Elicits a Mixed TH1 TH2 Immune Responseand Induce Protection in Mice Challenged with Brucella abortus 554 Independelntly of the Adjuvant Formulation Used

C A, VELIKOVSKI; CASSATARO J,; ESTEIN S,; BOWDEN R,; BRUNO L,; CARLOS ALBERTO FOSSATI; GIAMBARTOLOMEI GH,

INFECTION AND IMMUNITY

AMER SOC MICROBIOLOGY

Año: 2003 vol. 71 p. 5750 - 5755

0019-9567

The immunogenicity and protective efficacy of recombinant lumazine synthase from Brucella spp. (rBLS)administered with different adjuvants was evaluated in mice. Mice were immunized with rBLS in the absenceor the presence of aluminum hydroxide gel (BLS-Al), monophosphoryl lipid A (BLS-MPA), or incompleteFreund?s adjuvant (BLS-IFA). rBLS per se induced a vigorous immunoglobulin G (IgG) response, with hightiters of IgG1 as well as IgG2. All the adjuvants increased this response; the BLS-IFA formulation was the mosteffective at inducing BLS-specific IgG antibodies. In addition, after in vitro stimulation with rBLS, spleen cellsfrom BLS-IFA-, BLS-Al-, or BLS-MPA-immunized mice proliferated and produced interleukin-2 (IL-2), gammainterferon (IFN-
), IL-10, and IL-4, suggesting the induction of a mixed Th1-Th2 response. Immunization withrBLS protected mice against challenge with B. abortus 544. The levels of protection in the spleen were similarfor all adjuvants, but only BLS-Al and BLS-IFA were effective in the liver. Our results indicate that BLS mightbe a useful candidate for the development of subunit vaccines against brucellosis, since it elicits antigen-specificcellular responses, with production of IFN-
and protection, independently of the adjuvant formulation used.