• Vaccine Name: Brucella melitensis outer membrane vesicle subunit vaccine
• Target Pathogen: Brucella spp.
• Target Disease: Brucellosis
• Vaccine Ontology ID: VO_0009292
• Type: Subunit vaccine
• Status: Research
• Host Species for Licensed Use: Goat
• Host Species as Laboratory Animal Model: Mus musculus (BALB/c mice); Mus musculus
• Antigen: outer membrane vesicles
• Adjuvant: Pluronic P85 | Poly(I:C) or CpG ODN 1826 plus Montanide ISA 70 VG
• Preparation: OMVs administered twice during antibiotic therapy. (Jain-Gupta et al, 2014)
  OMVs combined with Pluronic P85 as an adjuvant (Jain-Gupta et al, 2012)
  OMVs formulated with either Poly(I:C) or a combination of CpG ODN 1826 plus Montanide ISA 70 VG adjuvants. (Golshani et al, 2020)
  OMVs derived from Brucella melitensis M5 strain (OMVs-M5) with weak activation of innate immunity and no cytotoxicity in ex vivo assays. (Huang et al, 2025)
• Description: OMVs from Brucella melitensis have been shown to be effective vaccines against B. melitensis challenge in mice. Efficacy: No additive effect on clearance of B. melitensis; however, mice receiving OMVs with antibiotics exhibited no Brucella replication post-treatment compared to antibiotics alone; mice receiving only vaccines did not show significant clearance. Immune response: OMV vaccinated mice developed significantly higher anti-Brucella IgG antibody titers at end of treatment compared to mice receiving only antibiotics; no increased IFN-γ production by splenocytes upon stimulation. (Jain-Gupta et al, 2014)
  Outer membrane vesicles (OMVs) from Brucella melitensis have been shown to provide protection similar to the live attenuated strain Rev. 1 vaccine in mice but without the associated risks of live vaccines. Efficacy: Pluronic P85 enhanced the protection provided by OMVs against Brucella melitensis challenge in mice; P85 alone also improved bacterial clearance compared to saline controls Immune response: Enhanced total IgG antibody production with OMVs plus P85; no increase in IFN-γ or IL-4 cytokine levels observed; P85 induced nonspecific protection mechanisms requiring further study (Jain-Gupta et al, 2012)
  Outer membrane vesicles (OMVs) are promising acellular vaccine candidates due to their heterogeneous composition and diverse functions. Efficacy: Both vaccine regimens induced protective levels significantly higher than the Brucella melitensis strain Rev. 1 live vaccine. Immune response: Both vaccine regimens induced strong Th1-biased immune responses. (Golshani et al, 2020)
  This study investigated the protective immunity conferred by outer membrane vesicles (OMVs) derived from Brucella melitensis M5 strain. Efficacy: All three immunization routes (intramuscular, subcutaneous, intranasal) showed comparable protective efficacy characterized by significantly reduced bacterial burdens and milder histopathological lesions in the spleen. Immune response: Robust humoral immunity and CD4+ T cell-mediated immune responses were elicited by all three routes of immunization; intramuscular and subcutaneous routes induced severe reactogenicity initially, whereas intranasal did not. (Huang et al, 2025)

Mouse Response

• Immune Response: Enhanced total IgG antibody production with OMVs plus P85; no increase in IFN-γ or IL-4 cytokine levels observed; P85 induced nonspecific protection mechanisms requiring further study (Jain-Gupta et al, 2012)
• Challenge Protocol: In vitro macrophage stimulation assays measuring TNF-α secretion; in vivo mouse challenge model with Brucella melitensis to assess protection and bacterial clearance. (Jain-Gupta et al, 2012)
• Efficacy: Pluronic P85 enhanced the protection provided by OMVs against Brucella melitensis challenge in mice; P85 alone also improved bacterial clearance compared to saline controls (Jain-Gupta et al, 2012)
• Description: In vitro macrophage stimulation assays measuring TNF-α secretion; in vivo mouse challenge model with Brucella melitensis to assess protection and bacterial clearance (Jain-Gupta et al, 2012)

Mouse Response

• Host Strain: BALB/c
• Vaccination Protocol: BALB/c mice chronically infected with B. melitensis treated with sub-therapeutic doxycycline and gentamicin and vaccinated twice during therapy. (Jain-Gupta et al, 2014)
• Immune Response: OMV vaccinated mice developed significantly higher anti-Brucella IgG antibody titers at end of treatment compared to mice receiving only antibiotics; no increased IFN-γ production by splenocytes upon stimulation. (Jain-Gupta et al, 2014)
• Challenge Protocol: OMVs from Brucella melitensis have been shown to be effective vaccines against B. melitensis challenge in mice. (Jain-Gupta et al, 2014)
• Efficacy: No additive effect on clearance of B. melitensis; however, mice receiving OMVs with antibiotics exhibited no Brucella replication post-treatment compared to antibiotics alone; mice receiving only vaccines did not show significant clearance. (Jain-Gupta et al, 2014)
• Description: BALB/c mice chronically infected with B. melitensis treated with sub-therapeutic doxycycline and gentamicin and vaccinated twice during therapy. (Jain-Gupta et al, 2014)

Mouse Response

• Immune Response: Both vaccine regimens induced strong Th1-biased immune responses. (Golshani et al, 2020)
• Challenge Protocol: Evaluation of immune responses and protection levels against Brucella melitensis challenge in mice. (Golshani et al, 2020)
• Efficacy: Both vaccine regimens induced protective levels significantly higher than the Brucella melitensis strain Rev. 1 live vaccine. (Golshani et al, 2020)
• Description: Evaluation of immune responses and protection levels against Brucella melitensis challenge in mice. (Golshani et al, 2020)

Mouse Response

• Vaccination Protocol: Immunization of mice via intramuscular, subcutaneous, or intranasal routes. (Huang et al, 2025)
• Immune Response: Robust humoral immunity and CD4+ T cell-mediated immune responses were elicited by all three routes of immunization; intramuscular and subcutaneous routes induced severe reactogenicity initially, whereas intranasal did not. (Huang et al, 2025)
• Challenge Protocol: Immunization of mice via intramuscular, subcutaneous, or intranasal routes followed by challenge with a virulent Brucella melitensis strain; assessment of bacterial burdens, histopathological lesions, humoral immunity, and CD4+ T cell-mediated immune responses. (Huang et al, 2025)
• Efficacy: All three immunization routes (intramuscular, subcutaneous, intranasal) showed comparable protective efficacy characterized by significantly reduced bacterial burdens and milder histopathological lesions in the spleen. (Huang et al, 2025)
• Description: Immunization of mice via intramuscular, subcutaneous, or intranasal routes followed by challenge with a virulent Brucella melitensis strain; assessment of bacterial burdens, histopathological lesions, humoral immunity, and CD4+ T cell-mediated immune responses. (Huang et al, 2025)