Immunization with a single dose of a microencapsulated Brucella melitensis mutant enhances protection against wild-type challenge

Infect Immun. 2008 Jun;76(6):2448-55. doi: 10.1128/IAI.00767-07. Epub 2008 Mar 24.


The development of safe and efficacious immunization systems to prevent brucellosis is needed to overcome the disadvantages of the currently licensed vaccine strains that restrict their use in humans. Alginate microspheres coated with a protein of the parasite Fasciola hepatica (vitelline protein B [VpB]) and containing live Brucella melitensis attenuated mutant vjbR::Tn5 (BMEII1116) were evaluated for vaccine efficacy and immunogenicity in mice. A single immunization dose in BALB/c mice with the encapsulated vjbR mutant improved protection against wild-type B. melitensis 16M challenge compared to the nonencapsulated vaccine strain (P < 0.05). The encapsulated mutant was also shown to induce a sustained elevation of Immunoglobulin G levels. Cytokine secretion from spleen cells of mice vaccinated with the encapsulated vjbR::Tn5 revealed elevated secretion of gamma interferon and interleukin-12, but no interleukin-4, suggesting an induction of a T helper 1 response reflecting the enhanced immunity associated with microencapsulation. Together, these results suggest that microencapsulation of live attenuated organisms offers the ability to increase the efficacy of vaccine candidates.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Animals
  • Antibodies, Bacterial / blood
  • Bacterial Vaccines / administration & dosage
  • Bacterial Vaccines / immunology*
  • Brucella melitensis / genetics
  • Brucella melitensis / immunology*
  • Brucella melitensis / pathogenicity
  • Brucellosis / immunology
  • Brucellosis / prevention & control*
  • Capsules
  • Cytokines / biosynthesis
  • Delayed-Action Preparations
  • Female
  • Immunization
  • Immunoglobulin G / blood
  • Injections, Intraperitoneal
  • Macrophages / microbiology
  • Mice
  • Mice, Inbred BALB C
  • Mutation
  • Random Allocation
  • Spleen / immunology
  • Spleen / microbiology
  • Vaccines, Attenuated / administration & dosage
  • Vaccines, Attenuated / immunology
  • Virulence


  • Antibodies, Bacterial
  • Bacterial Vaccines
  • Capsules
  • Cytokines
  • Delayed-Action Preparations
  • Immunoglobulin G
  • Vaccines, Attenuated