The recombinant Omp31 from Brucella melitensis alone or associated with rough lipopolysaccharide induces protection against Brucella ovis infection in BALB/c mice

• Published in: Microbes and infection 2003-02, Vol.5 (2), p.85-93
• Main Authors: Estein, Silvia M, Cassataro, Juliana, Vizcaíno, Nieves, Zygmunt, Michel S, Cloeckaert, Axel, Bowden, Raúl A
• Format: Article
• Language: English
• Subjects: Animals; Antibodies, Bacterial - blood; Bacterial Outer Membrane Proteins - genetics; Bacterial Outer Membrane Proteins - immunology; Bacterial Vaccines - administration & dosage; Bacterial Vaccines - immunology; Bacteriological methods and techniques used in bacteriology; Bacteriology; Biological and medical sciences; Brucella; Brucella - immunology; Brucella - metabolism; Brucella - pathogenicity; Brucella melitensis - genetics; Brucella melitensis - immunology; Brucella melitensis - metabolism; Brucellosis - prevention & control; Female; Fundamental and applied biological sciences. Psychology; Immunization; Life Sciences; Lipopolysaccharides - immunology; Mice; Mice, Inbred BALB C; Microbiology; Outer membrane protein; Recombinant Proteins - genetics; Recombinant Proteins - immunology; Sheep; Spleen - microbiology; Vaccine
• ISSN: 1286-4579; 1769-714X
• DOI: 10.1016/S1286-4579(02)00075-8

Immunogenicity and protective activity against Brucella ovis of detergent-extracted recombinant Omp31 (rOmp31 extract) from Brucella melitensis produced in Escherichia coli, purified rough lipopolysaccharide from B. ovis (R-LPS) and a mixture of rOmp31 extract and R-LPS (rOmp31 extract + R-LPS) were assessed in BALB/c mice. The experimental vaccines were compared with a hot saline extract (HS extract) from B. ovis mainly composed of outer membrane proteins (OMPs) and R-LPS, and known to be protective in mice against a B. ovis infection. Serum antibodies to Omp31 and R-LPS were detected in the corresponding mice using Western blotting with B. ovis whole-cell lysates and ELISA with purified antigens. Protection was evaluated by comparing the levels of infection in the spleens of vaccinated mice challenged with B. ovis. A significantly lower number of B. ovis colony-forming units in spleens relative to unimmunized (saline injected) controls were considered as protection. Mice immunized with rOmp31 extract or rOmp31 extract mixed with R-LPS developed antibodies that bound to the B. ovis surface with similar titers. Vaccination with rOmp31 extract plus R-LPS provided the best protection level, which was comparable with that given by HS extract. Similar protection was also obtained with rOmp31 extract alone and, to a lesser degree, with R-LPS. Comparisons between groups showed that an extract from E. coli-pUC19 (devoid of Omp31) provided no protection relative to either HS extract, rOmp31 extract or rOmp31 extract mixed with R-LPS. In conclusion, the recombinant Omp31 associated or not with B. ovis R-LPS, could be an interesting candidate for a subcellular vaccine against B. ovis infection.