Aerogenic Vaccination With a Burkholderia mallei Auxotroph Protects Against Aerosol-Initiated Glanders in Mice
ARMY MEDICAL RESEARCH INST OF INFECTIOUS DISEASES FORT DETRICK MD
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Burkholderia mallei is an obligate mammalian pathogen that causes the zoonotic disease glanders. Two live attenuated B. mallei strains, a capsule mutant and a branched-chain amino acid auxotroph, were evaluated for use as vaccines against aerosol-initiated glanders in mice. Animals were aerogenically vaccinated and serum samples were obtained before aerosol challenge with a high-dose 300 times the LD50 of B. mallei ATCC 23344. Mice vaccinated with the capsule mutant developed a Th2-like Ig subclass antibody response and none survived beyond 5 days. In comparison, the auxotrophic mutant elicited a Th1-like Ig subclass antibody response and 25 of the animals survived for 1 month postchallenge. After a low-dose 5 times the LD50 aerosol challenge, the survival rates of auxotroph-vaccinated and unvaccinated animals were 50 and 0, respectively. Thus, live attenuated strains that promote a Th1-like Ig response may serve as promising vaccine candidates against aerosol infection with B. mallei.
- Medicine and Medical Research