Isolated chimeric proteins including up to ten copies of peptides, polypeptides or protein domains inserted in the amino termini of the Brucella spp. Lumazine synthase enzyme. Isolated nucleotide sequences codifying the chimeric proteins. Vectors, plasmids and transformed cells used for expressing the proteins. Monoclonal and polyclonal antibodies induced by the chimeric proteins. Hybridomas producing the monoclonal antibodies. Vaccines and pharmaceutical compounds including the chimeric proteins, nucleotide sequences and antibodies. A method to induce an immune response in higher organisms including the administration of effective amounts of the vaccines and pharmaceutical compounds. Biosensors including the chimeric proteins. Protein conjugates formed by the chimeric proteins and a ligand bound by means of covalent and noncovalent bonds. Uses of the chimeric proteins, nucleotide sequences, vectors, plasmids, transformed cells, antibodies, hybridomas, conjugates, biosensors, vaccines and pharmaceutical compounds. The quaternary structure of the chimeric proteins.
