Limits...
Complete Protection against Pneumonic and Bubonic Plague after a Single Oral Vaccination.

Derbise A, Hanada Y, Khalifé M, Carniel E, Demeure CE - PLoS Negl Trop Dis (2015)

Bottom Line: This candidate vaccine however failed to confer full protection against bubonic plague and did not produce F1 stably.It involved cells with a Th1-Th17 effector profile, producing IFNγ, IL-17, and IL-10.To our knowledge, VTnF1 is the only plague vaccine ever reported that could provide high and durable protection against the two forms of plague after a single oral administration.

View Article: PubMed Central - PubMed

Affiliation: Unité de recherche Yersinia, Institut Pasteur, Paris, France.

ABSTRACT

Background: No efficient vaccine against plague is currently available. We previously showed that a genetically attenuated Yersinia pseudotuberculosis producing the Yersinia pestis F1 antigen was an efficient live oral vaccine against pneumonic plague. This candidate vaccine however failed to confer full protection against bubonic plague and did not produce F1 stably.

Methodology/principal findings: The caf operon encoding F1 was inserted into the chromosome of a genetically attenuated Y. pseudotuberculosis, yielding the VTnF1 strain, which stably produced the F1 capsule. Given orally to mice, VTnF1 persisted two weeks in the mouse gut and induced a high humoral response targeting both F1 and other Y. pestis antigens. The strong cellular response elicited was directed mostly against targets other than F1, but also against F1. It involved cells with a Th1-Th17 effector profile, producing IFNγ, IL-17, and IL-10. A single oral dose (108 CFU) of VTnF1 conferred 100% protection against pneumonic plague using a high-dose challenge (3,300 LD50) caused by the fully virulent Y. pestis CO92. Moreover, vaccination protected 100% of mice from bubonic plague caused by a challenge with 100 LD50 Y. pestis and 93% against a high-dose infection (10,000 LD50). Protection involved fast-acting mechanisms controlling Y. pestis spread out of the injection site, and the protection provided was long-lasting, with 93% and 50% of mice surviving bubonic and pneumonic plague respectively, six months after vaccination. Vaccinated mice also survived bubonic and pneumonic plague caused by a high-dose of non-encapsulated (F1-) Y. pestis.

Significance: VTnF1 is an easy-to-produce, genetically stable plague vaccine candidate, providing a highly efficient and long-lasting protection against both bubonic and pneumonic plague caused by wild type or un-encapsulated (F1-negative) Y. pestis. To our knowledge, VTnF1 is the only plague vaccine ever reported that could provide high and durable protection against the two forms of plague after a single oral administration.

No MeSH data available.


Related in: MedlinePlus

F1 capsule production.(A) V674, V674pF1, and VTnF1 bacteria grown at 37°C were re-suspended in India ink and observed by microscopy. (B) To evaluate the stability of F1 production, isolated colonies of Y. pestis CO92, or Y. pseudotuberculosis V674pF1, and VTnF1 were obtained after three subcultures in vitro. Isolated VTnF1 colonies were also obtained by culturing an homogenate of Peyer’s patches taken from mice previously inoculated with VTnF1 (108 CFU i.g.; noted "in vivo"). Serial dilutions of bacteria were tested using an F1-specific ELISA and the F1 index shown was calculated as 1/CFU yielding DO450nm = 1 in the ELISA. The un-encapsulated V674 was used as a negative control. (C) F1 production by VTnF1 was compared to that of Y. pestis CO92 after growth at 28°C or 37°C, using an F1-specific ELISA, and CO92Δcaf was used as negative control.
© Copyright Policy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4608741&req=5

pntd.0004162.g001: F1 capsule production.(A) V674, V674pF1, and VTnF1 bacteria grown at 37°C were re-suspended in India ink and observed by microscopy. (B) To evaluate the stability of F1 production, isolated colonies of Y. pestis CO92, or Y. pseudotuberculosis V674pF1, and VTnF1 were obtained after three subcultures in vitro. Isolated VTnF1 colonies were also obtained by culturing an homogenate of Peyer’s patches taken from mice previously inoculated with VTnF1 (108 CFU i.g.; noted "in vivo"). Serial dilutions of bacteria were tested using an F1-specific ELISA and the F1 index shown was calculated as 1/CFU yielding DO450nm = 1 in the ELISA. The un-encapsulated V674 was used as a negative control. (C) F1 production by VTnF1 was compared to that of Y. pestis CO92 after growth at 28°C or 37°C, using an F1-specific ELISA, and CO92Δcaf was used as negative control.

Mentions: Strain VTnF1 was constructed by inserting the caf operon encoding F1 [17] into the chromosome of the attenuated Y. pseudotuberculosis V674, using mini-Tn7 transposon technology [18]. F1 capsule production by recombinant VTnF1 grown at 37°C in LB broth was tested using an F1-specific rapid dipstick test [21], which was clearly F1 positive (S1 Fig). Microscopic visualization of VTnF1 in India ink revealed that all VTnF1 bacterial cells produced the F1 capsule, as visualized by the repulsion of ink particles with comparable thickness (Fig 1A). This contrasted with V674pF1 cultures, which displayed encapsulated and non-encapsulated bacteria. To quantify F1 capsule production, isolated colonies obtained after growth in LB broth at 37°C were tested using an F1-specific ELISA. All VTnF1 colonies were F1 positive and their F1 levels were homogenous (Fig 1B), whereas V674pF1 colonies exhibited various levels of F1 at their surface, indicating both heterogeneity and instability of F1 production. VTnF1 produced as much F1 as Y. pestis, and this production was temperature-dependent (Fig 1C).


Complete Protection against Pneumonic and Bubonic Plague after a Single Oral Vaccination.

Derbise A, Hanada Y, Khalifé M, Carniel E, Demeure CE - PLoS Negl Trop Dis (2015)

F1 capsule production.(A) V674, V674pF1, and VTnF1 bacteria grown at 37°C were re-suspended in India ink and observed by microscopy. (B) To evaluate the stability of F1 production, isolated colonies of Y. pestis CO92, or Y. pseudotuberculosis V674pF1, and VTnF1 were obtained after three subcultures in vitro. Isolated VTnF1 colonies were also obtained by culturing an homogenate of Peyer’s patches taken from mice previously inoculated with VTnF1 (108 CFU i.g.; noted "in vivo"). Serial dilutions of bacteria were tested using an F1-specific ELISA and the F1 index shown was calculated as 1/CFU yielding DO450nm = 1 in the ELISA. The un-encapsulated V674 was used as a negative control. (C) F1 production by VTnF1 was compared to that of Y. pestis CO92 after growth at 28°C or 37°C, using an F1-specific ELISA, and CO92Δcaf was used as negative control.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4608741&req=5

pntd.0004162.g001: F1 capsule production.(A) V674, V674pF1, and VTnF1 bacteria grown at 37°C were re-suspended in India ink and observed by microscopy. (B) To evaluate the stability of F1 production, isolated colonies of Y. pestis CO92, or Y. pseudotuberculosis V674pF1, and VTnF1 were obtained after three subcultures in vitro. Isolated VTnF1 colonies were also obtained by culturing an homogenate of Peyer’s patches taken from mice previously inoculated with VTnF1 (108 CFU i.g.; noted "in vivo"). Serial dilutions of bacteria were tested using an F1-specific ELISA and the F1 index shown was calculated as 1/CFU yielding DO450nm = 1 in the ELISA. The un-encapsulated V674 was used as a negative control. (C) F1 production by VTnF1 was compared to that of Y. pestis CO92 after growth at 28°C or 37°C, using an F1-specific ELISA, and CO92Δcaf was used as negative control.
Mentions: Strain VTnF1 was constructed by inserting the caf operon encoding F1 [17] into the chromosome of the attenuated Y. pseudotuberculosis V674, using mini-Tn7 transposon technology [18]. F1 capsule production by recombinant VTnF1 grown at 37°C in LB broth was tested using an F1-specific rapid dipstick test [21], which was clearly F1 positive (S1 Fig). Microscopic visualization of VTnF1 in India ink revealed that all VTnF1 bacterial cells produced the F1 capsule, as visualized by the repulsion of ink particles with comparable thickness (Fig 1A). This contrasted with V674pF1 cultures, which displayed encapsulated and non-encapsulated bacteria. To quantify F1 capsule production, isolated colonies obtained after growth in LB broth at 37°C were tested using an F1-specific ELISA. All VTnF1 colonies were F1 positive and their F1 levels were homogenous (Fig 1B), whereas V674pF1 colonies exhibited various levels of F1 at their surface, indicating both heterogeneity and instability of F1 production. VTnF1 produced as much F1 as Y. pestis, and this production was temperature-dependent (Fig 1C).

Bottom Line: This candidate vaccine however failed to confer full protection against bubonic plague and did not produce F1 stably.It involved cells with a Th1-Th17 effector profile, producing IFNγ, IL-17, and IL-10.To our knowledge, VTnF1 is the only plague vaccine ever reported that could provide high and durable protection against the two forms of plague after a single oral administration.

View Article: PubMed Central - PubMed

Affiliation: Unité de recherche Yersinia, Institut Pasteur, Paris, France.

ABSTRACT

Background: No efficient vaccine against plague is currently available. We previously showed that a genetically attenuated Yersinia pseudotuberculosis producing the Yersinia pestis F1 antigen was an efficient live oral vaccine against pneumonic plague. This candidate vaccine however failed to confer full protection against bubonic plague and did not produce F1 stably.

Methodology/principal findings: The caf operon encoding F1 was inserted into the chromosome of a genetically attenuated Y. pseudotuberculosis, yielding the VTnF1 strain, which stably produced the F1 capsule. Given orally to mice, VTnF1 persisted two weeks in the mouse gut and induced a high humoral response targeting both F1 and other Y. pestis antigens. The strong cellular response elicited was directed mostly against targets other than F1, but also against F1. It involved cells with a Th1-Th17 effector profile, producing IFNγ, IL-17, and IL-10. A single oral dose (108 CFU) of VTnF1 conferred 100% protection against pneumonic plague using a high-dose challenge (3,300 LD50) caused by the fully virulent Y. pestis CO92. Moreover, vaccination protected 100% of mice from bubonic plague caused by a challenge with 100 LD50 Y. pestis and 93% against a high-dose infection (10,000 LD50). Protection involved fast-acting mechanisms controlling Y. pestis spread out of the injection site, and the protection provided was long-lasting, with 93% and 50% of mice surviving bubonic and pneumonic plague respectively, six months after vaccination. Vaccinated mice also survived bubonic and pneumonic plague caused by a high-dose of non-encapsulated (F1-) Y. pestis.

Significance: VTnF1 is an easy-to-produce, genetically stable plague vaccine candidate, providing a highly efficient and long-lasting protection against both bubonic and pneumonic plague caused by wild type or un-encapsulated (F1-negative) Y. pestis. To our knowledge, VTnF1 is the only plague vaccine ever reported that could provide high and durable protection against the two forms of plague after a single oral administration.

No MeSH data available.


Related in: MedlinePlus