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Recombinant Salmonella Expressing Burkholderia mallei LPS O Antigen Provides Protection in a Murine Model of Melioidosis and Glanders.

Moustafa DA, Scarff JM, Garcia PP, Cassidy SK, DiGiandomenico A, Waag DM, Inzana TJ, Goldberg JB - PLoS ONE (2015)

Bottom Line: Consequently efforts are directed towards the development of an efficacious and safe vaccine.Lipopolysaccharide (LPS) is an immunodominant antigen and potent stimulator of host immune responses.These results suggest that live-attenuated SL3261 expressing B. mallei O antigen is a promising platform for developing a safe and effective vaccine.

View Article: PubMed Central - PubMed

Affiliation: Department of Microbiology, Immunology and Cancer Biology, University of Virginia, Charlottesville, Virginia, United States of America; Department of Pediatrics, Emory University School of Medicine and Children's Hospital of Atlanta, Inc., Atlanta, Georgia, United States of America.

ABSTRACT
Burkholderia pseudomallei and Burkholderia mallei are the etiologic agents of melioidosis and glanders, respectively. These bacteria are highly infectious via the respiratory route and can cause severe and often fatal diseases in humans and animals. Both species are considered potential agents of biological warfare; they are classified as category B priority pathogens. Currently there are no human or veterinary vaccines available against these pathogens. Consequently efforts are directed towards the development of an efficacious and safe vaccine. Lipopolysaccharide (LPS) is an immunodominant antigen and potent stimulator of host immune responses. B. mallei express LPS that is structurally similar to that expressed by B. pseudomallei, suggesting the possibility of constructing a single protective vaccine against melioidosis and glanders. Previous studies of others have shown that antibodies against B. mallei or B. pseudomallei LPS partially protect mice against subsequent lethal virulent Burkholderia challenge. In this study, we evaluated the protective efficacy of recombinant Salmonella enterica serovar Typhimurium SL3261 expressing B. mallei O antigen against lethal intranasal infection with Burkholderia thailandensis, a surrogate for biothreat Burkholderia spp. in a murine model that mimics melioidosis and glanders. All vaccine-immunized mice developed a specific antibody response to B. mallei and B. pseudomallei O antigen and to B. thailandensis and were significantly protected against challenge with a lethal dose of B. thailandensis. These results suggest that live-attenuated SL3261 expressing B. mallei O antigen is a promising platform for developing a safe and effective vaccine.

No MeSH data available.


Related in: MedlinePlus

Histopathological changes in response to intranasal challenge with B. thailandensis E264.Lungs of vaccinated BALB/c mice were isolated in their entirety at 24 (A-C) and 72 h (D-F) post-infection with 5 x 106 CFU B. thailandensis (5 x LD50). The tracheas of each animal were exposed and inflated with 0.3 ml of 10% neutral-buffered formalin and immediately immersed in the same fixative. Livers (G-I) and spleens (K-L) were also used for histology; organs were collected under the same conditions. All samples were processed by standard paraffin embedding methods; sections were cut 2 mM thick and stained with haematoxylin-eosin (H & E). Preparation of tissue sections was performed by the University of Virginia Research Histology Core Facility. Tissue sections were examined by a veterinary pathologist who was blinded to animal group assignments. Sections A, B, C, D, E, and F are shown in magnification, 10x; representative sections a, b, c, d, e, and f are in magnification, 40x. Liver and spleen sections are shown in magnifications 10x and 5x, respectively.
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pone.0132032.g005: Histopathological changes in response to intranasal challenge with B. thailandensis E264.Lungs of vaccinated BALB/c mice were isolated in their entirety at 24 (A-C) and 72 h (D-F) post-infection with 5 x 106 CFU B. thailandensis (5 x LD50). The tracheas of each animal were exposed and inflated with 0.3 ml of 10% neutral-buffered formalin and immediately immersed in the same fixative. Livers (G-I) and spleens (K-L) were also used for histology; organs were collected under the same conditions. All samples were processed by standard paraffin embedding methods; sections were cut 2 mM thick and stained with haematoxylin-eosin (H & E). Preparation of tissue sections was performed by the University of Virginia Research Histology Core Facility. Tissue sections were examined by a veterinary pathologist who was blinded to animal group assignments. Sections A, B, C, D, E, and F are shown in magnification, 10x; representative sections a, b, c, d, e, and f are in magnification, 40x. Liver and spleen sections are shown in magnifications 10x and 5x, respectively.

Mentions: The histopathological changes in the lungs, livers, and spleens of PBS-, vector-, and vaccine-immunized mice following challenge with B. thailandenis at 24 and 72 h post-infection were assessed in an independent experiment. We noted extensive signs of inflammation in the lung sections of PBS mice that succumbed to intranasal challenge with B. thailandensis. At 24 h, lung sections from this group displayed multifocal areas of hemorrhage intermixed with areas of mild to moderate infiltration of neutrophils Fig 5A and 5a. By 72 h, lung sections from the same group displayed multifocal to diffuse hemorrhage, necrosis and edema intermixed with multifocal areas of severe infiltration of neutrophils, and focal aggregates of hemosiderin-laden macrophages. The bronchi showed moderate infiltration of neutrophils often admixed with large numbers of bacterial colonies Fig 5B and 5b. Lung sections from vector-immunized animals at 24 h displayed signs of congestion, multifocal areas of hemorrhage, and moderate infiltration of neutrophils and macrophages. Multifocal peri-bronchial infiltration of moderate numbers of plasma cells and lymphocytes were also noted Fig 5C and 5c. At 72 h post-infection with B. thailandensis, the alveolar walls were thickened by Type II cell hyperplasia and infiltration of moderate numbers of neutrophils Fig 5D and 5d. At 24 h post-infection, lung sections of vaccine-immunized mice displayed multifocal areas of hemorrhage. The alveolar walls are diffusely thickened by type II cell hyperplasia Fig 5E and 5e. While at 72 h, infiltration of lymphocytes and plasma cells multifocal areas of severe infiltration of foamy macrophages, neutrophils, and hemosiderin-laden macrophages were noted in the peri- bronchial and parenchyma in lung sections of this group Fig 5F and 5f.


Recombinant Salmonella Expressing Burkholderia mallei LPS O Antigen Provides Protection in a Murine Model of Melioidosis and Glanders.

Moustafa DA, Scarff JM, Garcia PP, Cassidy SK, DiGiandomenico A, Waag DM, Inzana TJ, Goldberg JB - PLoS ONE (2015)

Histopathological changes in response to intranasal challenge with B. thailandensis E264.Lungs of vaccinated BALB/c mice were isolated in their entirety at 24 (A-C) and 72 h (D-F) post-infection with 5 x 106 CFU B. thailandensis (5 x LD50). The tracheas of each animal were exposed and inflated with 0.3 ml of 10% neutral-buffered formalin and immediately immersed in the same fixative. Livers (G-I) and spleens (K-L) were also used for histology; organs were collected under the same conditions. All samples were processed by standard paraffin embedding methods; sections were cut 2 mM thick and stained with haematoxylin-eosin (H & E). Preparation of tissue sections was performed by the University of Virginia Research Histology Core Facility. Tissue sections were examined by a veterinary pathologist who was blinded to animal group assignments. Sections A, B, C, D, E, and F are shown in magnification, 10x; representative sections a, b, c, d, e, and f are in magnification, 40x. Liver and spleen sections are shown in magnifications 10x and 5x, respectively.
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Related In: Results  -  Collection

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getmorefigures.php?uid=PMC4492786&req=5

pone.0132032.g005: Histopathological changes in response to intranasal challenge with B. thailandensis E264.Lungs of vaccinated BALB/c mice were isolated in their entirety at 24 (A-C) and 72 h (D-F) post-infection with 5 x 106 CFU B. thailandensis (5 x LD50). The tracheas of each animal were exposed and inflated with 0.3 ml of 10% neutral-buffered formalin and immediately immersed in the same fixative. Livers (G-I) and spleens (K-L) were also used for histology; organs were collected under the same conditions. All samples were processed by standard paraffin embedding methods; sections were cut 2 mM thick and stained with haematoxylin-eosin (H & E). Preparation of tissue sections was performed by the University of Virginia Research Histology Core Facility. Tissue sections were examined by a veterinary pathologist who was blinded to animal group assignments. Sections A, B, C, D, E, and F are shown in magnification, 10x; representative sections a, b, c, d, e, and f are in magnification, 40x. Liver and spleen sections are shown in magnifications 10x and 5x, respectively.
Mentions: The histopathological changes in the lungs, livers, and spleens of PBS-, vector-, and vaccine-immunized mice following challenge with B. thailandenis at 24 and 72 h post-infection were assessed in an independent experiment. We noted extensive signs of inflammation in the lung sections of PBS mice that succumbed to intranasal challenge with B. thailandensis. At 24 h, lung sections from this group displayed multifocal areas of hemorrhage intermixed with areas of mild to moderate infiltration of neutrophils Fig 5A and 5a. By 72 h, lung sections from the same group displayed multifocal to diffuse hemorrhage, necrosis and edema intermixed with multifocal areas of severe infiltration of neutrophils, and focal aggregates of hemosiderin-laden macrophages. The bronchi showed moderate infiltration of neutrophils often admixed with large numbers of bacterial colonies Fig 5B and 5b. Lung sections from vector-immunized animals at 24 h displayed signs of congestion, multifocal areas of hemorrhage, and moderate infiltration of neutrophils and macrophages. Multifocal peri-bronchial infiltration of moderate numbers of plasma cells and lymphocytes were also noted Fig 5C and 5c. At 72 h post-infection with B. thailandensis, the alveolar walls were thickened by Type II cell hyperplasia and infiltration of moderate numbers of neutrophils Fig 5D and 5d. At 24 h post-infection, lung sections of vaccine-immunized mice displayed multifocal areas of hemorrhage. The alveolar walls are diffusely thickened by type II cell hyperplasia Fig 5E and 5e. While at 72 h, infiltration of lymphocytes and plasma cells multifocal areas of severe infiltration of foamy macrophages, neutrophils, and hemosiderin-laden macrophages were noted in the peri- bronchial and parenchyma in lung sections of this group Fig 5F and 5f.

Bottom Line: Consequently efforts are directed towards the development of an efficacious and safe vaccine.Lipopolysaccharide (LPS) is an immunodominant antigen and potent stimulator of host immune responses.These results suggest that live-attenuated SL3261 expressing B. mallei O antigen is a promising platform for developing a safe and effective vaccine.

View Article: PubMed Central - PubMed

Affiliation: Department of Microbiology, Immunology and Cancer Biology, University of Virginia, Charlottesville, Virginia, United States of America; Department of Pediatrics, Emory University School of Medicine and Children's Hospital of Atlanta, Inc., Atlanta, Georgia, United States of America.

ABSTRACT
Burkholderia pseudomallei and Burkholderia mallei are the etiologic agents of melioidosis and glanders, respectively. These bacteria are highly infectious via the respiratory route and can cause severe and often fatal diseases in humans and animals. Both species are considered potential agents of biological warfare; they are classified as category B priority pathogens. Currently there are no human or veterinary vaccines available against these pathogens. Consequently efforts are directed towards the development of an efficacious and safe vaccine. Lipopolysaccharide (LPS) is an immunodominant antigen and potent stimulator of host immune responses. B. mallei express LPS that is structurally similar to that expressed by B. pseudomallei, suggesting the possibility of constructing a single protective vaccine against melioidosis and glanders. Previous studies of others have shown that antibodies against B. mallei or B. pseudomallei LPS partially protect mice against subsequent lethal virulent Burkholderia challenge. In this study, we evaluated the protective efficacy of recombinant Salmonella enterica serovar Typhimurium SL3261 expressing B. mallei O antigen against lethal intranasal infection with Burkholderia thailandensis, a surrogate for biothreat Burkholderia spp. in a murine model that mimics melioidosis and glanders. All vaccine-immunized mice developed a specific antibody response to B. mallei and B. pseudomallei O antigen and to B. thailandensis and were significantly protected against challenge with a lethal dose of B. thailandensis. These results suggest that live-attenuated SL3261 expressing B. mallei O antigen is a promising platform for developing a safe and effective vaccine.

No MeSH data available.


Related in: MedlinePlus