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Attenuation of defined Brucella melitensis wboA mutants

Mikeljon P Nikolich1, Richard L Warren, Luther E Lindler

  • 1Walter Reed Army Institute of Research, Division of Bacterial & Rickettsial Diseases, Silver Spring, MD 20910, USA. mikeljon.nikolich@amedd.army.mil

Vaccine
|April 6, 2010
PubMed

Insights

Two new rough Brucella mutants were created as potential vaccine candidates. The double mutant WRRP1 showed significant attenuation in macrophages and mice, indicating its potential for safer Brucella vaccines.

Area of Science:

  • Microbiology
  • Immunology
  • Vaccine Development

Background:

  • Rough Brucella mutants are investigated as vaccine candidates due to their inability to induce seroconversion.
  • Brucella melitensis is a virulent pathogen requiring effective vaccine strategies.

Purpose of the Study:

  • To generate and characterize two defined, nonreverting rough mutants of Brucella melitensis 16M.
  • To evaluate the attenuated phenotype of these mutants in vitro and in vivo.

Main Methods:

  • Deletion mutagenesis was used to create wboA (WRR51) and wboA purEK (WRRP1) mutants.
  • Survival assays were performed in human monocyte-derived macrophages (hMDMs).
  • In vivo studies involved intraperitoneal infection of BALB/c mice.

Main Results:

  • The wboA purEK double mutant (WRRP1) exhibited significantly reduced survival in hMDMs compared to single mutants.
  • WRRP1 showed rapid clearance from BALB/c mice, persisting for less than 1 week.
  • Trans-complementation of the wboA mutation restored macrophage survival.

Conclusions:

  • The wboA purEK double mutant demonstrates significant attenuation, making it a promising candidate for Brucella vaccine development.
  • Targeted genetic modification can yield safe and effective Brucella vaccine strains.

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