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Mena-Bueno S, Poveda-Urkixo I, Irazoki O, Palacios L, Cava F, Zabalza-Baranguá A, Grilló MJ. Brucella melitensis Wzm/Wzt System: Changes in the Bacterial Envelope Lead to Improved Rev1Δwzm Vaccine Properties. Front Microbiol 2022; 13:908495. [PMID: 35875565 PMCID: PMC9306315 DOI: 10.3389/fmicb.2022.908495] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Accepted: 05/26/2022] [Indexed: 11/13/2022] Open
Abstract
The lipopolysaccharide (LPS) O-polysaccharide (O-PS) is the main virulence factor in Brucella. After synthesis in the cytoplasmic membrane, O-PS is exported to the periplasm by the Wzm/Wzt system, where it is assembled into a LPS. This translocation also engages a bactoprenol carrier required for further biosynthesis pathways, such as cell wall biogenesis. Targeting O-PS export by blockage holds great potential for vaccine development, but little is known about the biological implications of each Wzm/Wzt moiety. To improve this knowledge and to elucidate its potential application as a vaccine, we constructed and studied wzm/wzt single- and double-deletion mutants, using the attenuated strain Brucella melitensis Rev1 as the parental strain. This allowed us to describe the composition of Brucella peptidoglycan for the first time. We observed that these mutants lack external O-PS yet trigger changes in genetic transcription and in phenotypic properties associated with the outer membrane and cell wall. The three mutants are highly attenuated; unexpectedly, Rev1Δwzm also excels as an immunogenic and effective vaccine against B. melitensis and Brucella ovis in mice, revealing that low persistence is not at odds with efficacy. Rev1Δwzm is attenuated in BeWo trophoblasts, does not infect mouse placentas, and is safe in pregnant ewes. Overall, these attributes and the minimal serological interference induced in sheep make Rev1Δwzm a highly promising vaccine candidate.
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Affiliation(s)
- Sara Mena-Bueno
- Animal Health Department, Instituto de Agrobiotecnología (IdAB, CSIC-Gobierno de Navarra), Pamplona, Spain
- Agronomy, Biotecnology and Food Department, Universidad Pública de Navarra (UPNA), Pamplona, Spain
| | - Irati Poveda-Urkixo
- Animal Health Department, Instituto de Agrobiotecnología (IdAB, CSIC-Gobierno de Navarra), Pamplona, Spain
| | - Oihane Irazoki
- Laboratory for Molecular Infection Medicine Sweden, Department of Molecular Biology, Umeå Centre for Microbial Research, Umeå University, Umeå, Sweden
| | - Leyre Palacios
- Animal Health Department, Instituto de Agrobiotecnología (IdAB, CSIC-Gobierno de Navarra), Pamplona, Spain
| | - Felipe Cava
- Laboratory for Molecular Infection Medicine Sweden, Department of Molecular Biology, Umeå Centre for Microbial Research, Umeå University, Umeå, Sweden
| | - Ana Zabalza-Baranguá
- Animal Health Department, Instituto de Agrobiotecnología (IdAB, CSIC-Gobierno de Navarra), Pamplona, Spain
| | - María Jesús Grilló
- Animal Health Department, Instituto de Agrobiotecnología (IdAB, CSIC-Gobierno de Navarra), Pamplona, Spain
- *Correspondence: María Jesús Grilló,
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Xyloglucan based mucosal nanovaccine for immunological protection against brucellosis developed by supercritical fluid technology. INTERNATIONAL JOURNAL OF PHARMACEUTICS-X 2020; 2:100053. [PMID: 32776000 PMCID: PMC7397708 DOI: 10.1016/j.ijpx.2020.100053] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/15/2019] [Revised: 06/28/2020] [Accepted: 07/13/2020] [Indexed: 11/21/2022]
Abstract
Vaccines delivered via the mucosal route have logistic benefits over parenteral or intramuscular vaccines as they offer patient compliance. This study presents the first intranasal, controlled release, subunit nanovaccine comprising mucoadhesive tamarind seed polymer (xyloglucan) based nanoparticles produced using an efficient, environmentally compatible, and industrially scalable technique: rapid expansion of supercritical solution. The nanovaccine formulation aimed against brucellosis comprised xyloglucan nanoparticles loaded separately with antigenic acellular lipopolysaccharides from B. abortus (S19) and the immunoadjuvant quillaja saponin. The nanovaccine elicited prolonged humoral and cell-mediated immunity in female Balb/c mice. Nasal vaccination with the nanovaccine resulted in higher levels of mucosal IgA and IgG than with an aqueous solution of soluble lipopolysaccharides and quillaja saponin. Systemic immunity triggered by the nanovaccine was evidenced by higher IgG levels in sera post priming and boosting. The nanovaccine induced a mixed Th1/Th2 type of immunity with higher IgG2a levels and thus a polarized Th1 response. The results suggest that the nanovaccine administered by homologous nasal route can prime the immune system via the mucosal and systemic pathways and is a good candidate for vaccine delivery.
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A safe and molecular-tagged Brucella canis ghosts confers protection against virulent challenge in mice. Vet Microbiol 2017; 204:121-128. [PMID: 28532790 DOI: 10.1016/j.vetmic.2017.04.027] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2016] [Revised: 02/26/2017] [Accepted: 04/25/2017] [Indexed: 01/16/2023]
Abstract
Canine brucellosis, caused by Brucella canis, is a persistent infectious reproductive disease in dogs. The absence of effective treatment to the intracellular pathogen and the irreversible consequence of infection makes the need of a specific vaccine urgent. Bacterial ghosts (BGs) are the empty envelopes of bacteria with no genome content inside, which emerge as a proper vaccine candidate due to its intact outer antigen. It is generally derived from a genetically engineered strain, through the expression of Bacteriophage phiX174 lysis E gene upon induction. In this study, we combined the homologous recombination (HR) and bacterial ghost technologies, generating a genetically stable B. canis ghost strain which bears no drug resistance gene. When the ghost strain grows to OD600 of 0.6, 100% inactivation can be achieved under 42°C in 60h. The resultant BGs showed guaranteed safety and comparable immunogenicity to a live vaccine. The bacterial B0419 protein was depleted during HR process, which is subsequently proved to work as a molecular tag in distinguishing natural infection and BGs immunization through ELISA. Additionally, the BGs also conferred protection against B. canis RM6/66 and B. melitensis 16M. Therefore, the application of current BGs as a vaccine candidate and the corresponding serological diagnostic approach may provide better B. canis prevention strategy.
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