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Mayfield, PA, United States

Roset M.S.,CONICET | Fernandez L.G.,CONICET | DelVecchio V.G.,Vital Probes, Inc. | Briones G.,CONICET
Infection and Immunity | Year: 2013

Brucella is an intracellular bacterial pathogen that causes the worldwide zoonotic disease brucellosis. Brucella virulence relies on its ability to transition to an intracellular lifestyle within host cells. Thus, this pathogen must sense its intracellular localization and then reprogram gene expression for survival within the host cell. A comparative proteomic investigation was performed to identify differentially expressed proteins potentially relevant for Brucella intracellular adaptation. Two proteins identified as cyclophilins (CypA and CypB) were overexpressed in the intracellular environment of the host cell in comparison to laboratorygrown Brucella. To define the potential role of cyclophilins in Brucella virulence, a double-deletion mutant was constructed and its resulting phenotype was characterized. The Brucella abortus δcypAB mutant displayed increased sensitivity to environmental stressors, such as oxidative stress, pH, and detergents. In addition, the B. abortus δcypAB mutant strain had a reduced growth rate at lower temperature, a phenotype associated with defective expression of cyclophilins in other microorganisms. The B. abortus δcypAB mutant also displays reduced virulence in BALB/c mice and defective intracellular survival in HeLa cells. These findings suggest that cyclophilins are important for Brucella virulence and survival in the host cells. ©2013, American Society for Microbiology. Source


Grant
Agency: Department of Defense | Branch: Army | Program: SBIR | Phase: Phase I | Award Amount: 119.63K | Year: 2005

The objective of this proposal is to demonstrate the feasibility of utilizing bacterial ghosts (BG) with internally immobilized DNA minicircles as an enhanced non-viral DNA vaccine and delivery system. Current methodologies for delivering DNA vaccines are either inefficient, do not target the appropriate cell types, contain unnecessary genetic elements or fail to elicit a protective immune response in the absence of a protein antigen boost. BG are non-living bacterial envelopes. BG deliver DNA constructs and/or protein antigens to a wide variety of cell types, including dendritic cells and macrophages and do not require the addition of adjuvant to induce an immune response. DNA minicircles contain only the necessary promoter and gene elements for a vaccine candidate protein and can be attached to the interior of BG. Both BG and DNA minicircles can be easily modified to include a mixture of different ORFs for use as a multi-agent or multi-lifestage vaccine. In this proposal, BG will be created containing immobilized DNA minicircles with the gene sequences for Bacillus anthracis Protective Antigen (PA) and the Yersinia pestis F1 capsule. Mice will undergo a scheduled vaccination scheme and subsequent antibody and cellular mediated immune responses as well as protein expression will be assessed.


Grant
Agency: Department of Agriculture | Branch: | Program: SBIR | Phase: Phase I | Award Amount: 79.63K | Year: 2007

The objective of this proposal is to demonstrate the feasibility of utilizing bacterial ghosts (BG) as novel vaccines for aquaculture. Current vaccination strategies for the prevention of aquaculture diseases utilize traditional technologies including chemical or heat inactivation of cultured pathogens or live attenuated strains of pathogens. While some of these vaccines have proved to be efficacious, others have demonstrated sub-par immunogenicity and protection. BG are non-living Gram negative bacterial cell envelopes created after lysis with the cloned bacteriophage gene E. Production of BG does not alter the natural protein components of the cell, including many proteins important for interaction with immune system cells including dendritic cells and macrophages. Additionally, since BG retain these structures, they do not require the addition of adjuvant to induce an immune response In this Phase I proposal the feasibility of producing a BG based vaccine for use in the aquaculture industry will be assessed. To determine whether this is feasible, BG will be created from a known important aquaculture pathogen, Flavobacterium psychrophilum. F. psychrophilum is the etiologic agent of cold water disease which affects commercial aquaculture species such as rainbow trout and salmon. To date, there is no effective vaccine against this pathogen and development of such a vaccine is of great importance to the cold water aquaculture industry. F. psychrophilum BG will be tested for efficacy using a challenge model in trout. The long-term goal of this project is to develop safe and effective BG vaccine for commercialization and marketing to the aquaculture community.


Grant
Agency: Department of Defense | Branch: Army | Program: SBIR | Phase: Phase II | Award Amount: 726.31K | Year: 2006

The objective of this proposal is to demonstrate the effectiveness of bacterial ghosts (BG) with internally immobilized DNA minicircles as an enhanced non-viral DNA vaccine and delivery system. Current methodologies for delivering DNA vaccines are either inefficient, do not target the appropriate cell types, contain unnecessary genetic elements or fail to elicit a protective immune response in the absence of a protein antigen boost. BG are non-living bacterial envelopes that deliver DNA constructs and/or protein antigens to a wide variety of cell types, including dendritic cells and macrophages and do not require the addition of adjuvant to induce an immune response. DNA minicircles contain only the necessary promoter and gene elements for a vaccine candidate protein and can be attached to the interior of BG. Both BG and DNA minicircles can be easily modified to include a mixture of different ORFs for use as a multi-agent or multi-life stage vaccine. In this proposal, BG containing immobilized DNA minicircles with gene sequences for Bacillus anthracis and Yersinia pestis antigens will be used to vaccinate small animals. Animals will undergo a scheduled vaccination scheme, the immune response will be assessed and the animals will be challenged to determine the efficacy of the vaccine.


Grant
Agency: Department of Defense | Branch: Army | Program: SBIR | Phase: Phase II | Award Amount: 627.14K | Year: 2010

Malaria caused by Plasmodium falciparum results in serious illness and, if untreated, often leads to death. Although a number of candidate vaccines have progressed to clinical trials the efficacy rate of those vaccines was much lower than ideal. New methods for simultaneous presentation and immune stimulation of malarial antigens are needed in order to rapidly progress promising antigens into efficacious vaccines. Platforms that present antigen to the immune system in a particulate manner that mimics the structure of a natural pathogen may improve the effectiveness of a vaccine. Prior work has demonstrated that Vital Probes, Gene-Mediated Inactivated Vaccine (GeMI-Vax) platform in E. coli combined with malaria antigens results in a protective immune response in mouse models of malaria. The GeMI-Vax production method gently inactivates bacteria that are engineered to express malaria protein antigens. The resulting particle-based vaccine has inherent adjuvant activity and appropriately presents vaccine antigens and stimulates the immune system. Phase I SBIR work resulted in successful expression of malaria antigens in E. coli and Shigella. In Phase II, Shigella-GeMI-Vax expressing malaria antigens will be produced and tested in animal efficacy models. Demonstration of efficacy will lead to follow-on research and development efforts towards testing in human clinical trials.

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