Intracellular trafficking study of a RB51 B. abortus vaccinal strain isolated from cow milk

• Published in: Veterinary microbiology 2004-03, Vol.98 (3), p.307-312
• Main Authors: Arellano-Reynoso, Beatriz, Dı&#x0301, az-Aparicio, Efrén, Leal-Hernández, Marisela, Hernández, Laura, Gorvel, Jean-Pierre
• Format: Article
• Language: English
• Subjects: Animals; Applied microbiology; Bacterial Vaccines - immunology; Bacteriology; Biological and medical sciences; Brucella abortus; Brucella abortus - immunology; Brucella abortus - isolation & purification; Brucella abortus - metabolism; Brucella abortus - pathogenicity; Brucellosis - immunology; Brucellosis - microbiology; Brucellosis - veterinary; Cathepsin D - immunology; Cattle; Cattle Diseases - immunology; Cattle Diseases - microbiology; CHO Cells; Cricetinae; Endoplasmic Reticulum - immunology; Endoplasmic Reticulum - microbiology; Female; Fluorescent Antibody Technique, Indirect - veterinary; Fundamental and applied biological sciences. Psychology; Immunization - adverse effects; Immunization - veterinary; Intracellular trafficking; Membrane Proteins - immunology; Microbiology; Microscopy, Confocal - veterinary; Milk - microbiology; Miscellaneous; Phagosomes - immunology; Phagosomes - microbiology; RB51 vaccine; Vaccines, antisera, therapeutical immunoglobulins and monoclonal antibodies (general aspects); Vaccines, Attenuated - adverse effects; Vaccines, Attenuated - immunology; Vesicular Transport Proteins; Virulence
• ISSN: 0378-1135; 1873-2542
• DOI: 10.1016/j.vetmic.2003.10.024

Brucella is responsible for one of the major worldwide zoonoses. Over the last century, several vaccines have been used against brucellosis. Among these, the rough vaccine Brucella abortus RB51 was introduced with the idea that it would not interfere with the diagnosis of brucellosis. Recently, RB51 has been isolated from milk and vaginal exudates from vaccinated cows, thus raising the possibility of extensive bacterial replication in these animals. We hypothesized that shedding of RB51 might be related to a change in its intracellular cell cycle. Therefore, we have compared the intracellular trafficking in CHO cells of the virulent B. abortus 2308 and two RB51 strains, the vaccinal strain and the one isolated from cow milk. Both RB51 strains were transiently observed in phagosomes characterized by the presence of the early endosomal marker EEA1 and then were found in cathepsin D-enriched lysosomal compartments, in which they eventually underwent degradation at later post-infection times. In contrast, the virulent 2308 strain replicated within the endoplasmic reticulum. These results suggest that a change in intracellular trafficking cannot account for Brucella shedding in adult vaccinated cows.