Molecular typing of Mycobacterium bovis isolated in the south of Brazil.

Bovine tuberculosis is a major infectious disease of the cattle. In this study, 85 M. bovis isolates from 162 lymph nodes, obtained from a herd of cattle on a farm in southern Brazil, were evaluated using spoligotyping and VNTR.

Protection against lethal leptospirosis after vaccination with LipL32 coupled or coadministered with the B subunit of Escherichia coli heat-labile enterotoxin.

Leptospirosis, a worldwide zoonosis, lacks an effective, safe, and cross-protective vaccine. LipL32, the most abundant, immunogenic, and conserved surface lipoprotein present in all pathogenic species of Leptospira, is a promising antigen candidate for a recombinant vaccine. However, several studies have reported a lack of protection when this protein is used as a subunit vaccine.

Stable expression of Leptospira interrogans antigens in auxotrophic Mycobacterium bovis BCG.

Mycobacterium bovis BCG has been proposed as an effective live vector for multivalent vaccines. The development of mycobacterial genetic systems to express foreign antigens and the adjuvanticity of BCG are the basis for the potential use of this attenuated mycobacterium as a recombinant vaccine vector. Stable plasmid vectors without antibiotic resistance markers are needed for heterologous antigen expression in BCG.

Preliminary characterization of Mus musculus-derived pathogenic strains of Leptospira borgpetersenii serogroup Ballum in a hamster model.

Human and animal leptospirosis caused by Leptospira spp. belonging to serogroup Ballum has increased worldwide in the past decade. We report the isolation and serologic and molecular characterization of four L.

Characterization of virulence of Leptospira isolates in a hamster model.

Effort has been made to identify protective antigens in order to develop a recombinant vaccine against leptospirosis. Several attempts failed to conclusively demonstrate efficacy of vaccine candidates due to the lack of an appropriate model of lethal leptospirosis. The purposes of our study were: (i) to test the virulence of leptospiral isolates from Brazil, which are representative of important serogroups that cause disease in humans and animals; and (ii) to standardize the lethal dose 50% (LD(50)) for each of the virulent strains using a hamster (Mesocricetus auratus) model.

Recombinant Mycobacterium bovis BCG expressing the LipL32 antigen of Leptospira interrogans protects hamsters from challenge.

The bacillus Calmette--Guerin (BCG), a live attenuated Mycobacterium bovis strain is considered a promising candidate as a vector system for delivery of foreign antigens to the immune system. The gene coding for the Leptospira interrogans external membrane protein LipL32, a highly immunogenic antigen found in all pathogenic leptospira, was cloned into several mycobacterial vectors for expression in BCG. Hamsters immunized with recombinant BCG (rBCG) expressing LipL32 were protected against mortality (P View Article and Find Full Text PDF

Auxotrophic complementation as a selectable marker for stable expression of foreign antigens in Mycobacterium bovis BCG.

Mycobacterium bovis BCG has the potential to be an effective live vector for multivalent vaccines. However, most mycobacterial cloning vectors rely on antibiotic resistance genes as selectable markers, which would be undesirable in any practical vaccine. Here we report the use of auxotrophic complementation as a selectable marker that would be suitable for use in a recombinant vaccine.