Deletion of znuA virulence factor attenuates Brucella abortus and confers protection against wild-type challenge.
znuA is known to be an important factor for survival and normal growth under low Zn(2+) concentrations for Escherichia coli, Haemophilus spp., Neisseria gonorrhoeae, and Pasteurella multocida. We hypothesized that the znuA gene present in Brucella melitensis 16 M would be similar to znuA in B. abortus and questioned whether it may also be an important factor for growth and virulence of Brucella abortus. Using the B. melitensis 16 M genome sequence, primers were designed to construct a B. abortus deletion mutant. A znuA knockout mutation in B. abortus 2308 (DeltaznuA) was constructed and found to be lethal in low-Zn(2+) medium. When used to infect macrophages, DeltaznuA B. abortus showed minimal growth. Further study with DeltaznuA B. abortus showed that its virulence in BALB/c mice was attenuated, and most of the bacteria were cleared from the spleen within 8 weeks. Protection studies confirmed the DeltaznuA mutant as a potential live vaccine, since protection against wild-type B. abortus 2308 challenge was as effective as that obtained with the RB51 or S19 vaccine strain.
Yang
Xinghong
X
Veterinary Molecular Biology, Montana State University, Bozeman, MT 59717-3610, USA.
Becker
Todd
T
Walters
Nancy
N
Pascual
David W
DW
D000818:Animals; D001428:Bacterial Vaccines / Q000008:administration & dosage / Q000235:genetics / Q000276:immunology; D002003:Brucella abortus / Q000235:genetics* / Q000254:growth & development / Q000276:immunology* / Q000472:pathogenicity; D002006:Brucellosis / Q000276:immunology / Q000382:microbiology / Q000517:prevention & control*; D002460:Cell Line; D005260:Female; D017353:Gene Deletion; D008264:Macrophages / Q000276:immunology / Q000382:microbiology; D051379:Mice; D008807:Mice, Inbred BALB C; D037521:Virulence Factors / Q000235:genetics* / Q000302:isolation & purification; D015032:Zinc / Q000378:metabolism
D001428:Bacterial Vaccines; D037521:Virulence Factors; D015032:Zinc