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Whelan AO, Flick-Smith HC, Walker NJ, Abraham A, Levitz SM, Ostroff GR, Oyston PCF. A glucan-particle based tularemia subunit vaccine induces T-cell immunity and affords partial protection in an inhalation rat infection model. PLoS One 2024; 19:e0294998. [PMID: 38713688 PMCID: PMC11075878 DOI: 10.1371/journal.pone.0294998] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2023] [Accepted: 11/13/2023] [Indexed: 05/09/2024] Open
Abstract
Tularemia is a zoonotic disease caused by the facultative intracellular gram-negative bacterium Francisella tularensis. F. tularensis has a very low infection dose by the aerosol route which can result in an acute, and potentially lethal, infection in humans. Consequently, it is classified as a Category A bioterrorism agent by the US Centers for Disease Control (CDC) and is a pathogen of concern for the International Biodefence community. There are currently no licenced tularemia vaccines. In this study we report on the continued assessment of a tularemia subunit vaccine utilising β-glucan particles (GPs) as a vaccine delivery platform for immunogenic F. tularensis antigens. Using a Fischer 344 rat infection model, we demonstrate that a GP based vaccine comprising the F. tularensis lipopolysaccharide antigen together with the protein antigen FTT0814 provided partial protection of F344 rats against an aerosol challenge with a high virulence strain of F. tularensis, SCHU S4. Inclusion of imiquimod as an adjuvant failed to enhance protective efficacy. Moreover, the level of protection afforded was dependant on the challenge dose. Immunological characterisation of this vaccine demonstrated that it induced strong antibody immunoglobulin responses to both polysaccharide and protein antigens. Furthermore, we demonstrate that the FTT0814 component of the GP vaccine primed CD4+ and CD8+ T-cells from immunised F344 rats to express interferon-γ, and CD4+ cells to express interleukin-17, in an antigen specific manner. These data demonstrate the development potential of this tularemia subunit vaccine and builds on a body of work highlighting GPs as a promising vaccine platform for difficult to treat pathogens including those of concern to the bio-defence community.
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Affiliation(s)
- Adam O. Whelan
- CBR Division, Dstl Porton Down, Salisbury, United Kingdom
| | | | | | - Ambily Abraham
- University of Massachusetts Chan Medical School, Worcester, Massachusetts, United States of America
| | - Stuart M. Levitz
- University of Massachusetts Chan Medical School, Worcester, Massachusetts, United States of America
| | - Gary R. Ostroff
- University of Massachusetts Chan Medical School, Worcester, Massachusetts, United States of America
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Patnaik A, Rai SK, Dhaked RK. Recent Advancements and Novel Approaches Contributing to the Present Arsenal of Prophylaxis and Treatment Strategies Against Category A Bacterial Biothreat Agents. Indian J Microbiol 2023; 63:161-172. [PMID: 37325016 PMCID: PMC10220334 DOI: 10.1007/s12088-023-01075-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2022] [Accepted: 03/04/2023] [Indexed: 06/17/2023] Open
Abstract
Bacterial pathogens have always been a part of the ecosystem in which we thrive. Some pathogens have caused deadly outbreaks in the past and have been exploited as an agent of threat. Natural hotspots for these biological pathogens are widely distributed throughout the world and hence they remain clinically important. Technological advancement and change in general lifestyle has driven the evolution of these pathogens into more virulent and resistant variants. There has been a growing concern over the development of multidrug-resistant bacterial strains that could be used as bioweapons. This rapid change in pathogens also propels the field of science to develop and innovate new strategies and methodologies which are superior and safer to the existing ones. Some bacterial agents like-Bacillus anthracis, Yersinia pestis, Francisella tularensis and toxins produced by strains of Clostridium botulinum, have been segregated as Category A substances as they pose imminent threat to public health with a history of life threatening and catastrophic disease. This review highlights some encouraging developments and value additions in the current plan of action for protection against these select biothreat bacterial pathogens.
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Affiliation(s)
- Abhinandan Patnaik
- Biotechnology Division, Defence Research and Development Establishment, Jhansi Road, Gwalior, MP 474002 India
| | - Sharad Kumar Rai
- Biotechnology Division, Defence Research and Development Establishment, Jhansi Road, Gwalior, MP 474002 India
| | - Ram Kumar Dhaked
- Biotechnology Division, Defence Research and Development Establishment, Jhansi Road, Gwalior, MP 474002 India
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Freudenberger Catanzaro KC, Lahmers KK, Allen IC, Inzana TJ. Alginate microencapsulation of an attenuated O-antigen mutant of Francisella tularensis LVS as a model for a vaccine delivery vehicle. PLoS One 2022; 17:e0259807. [PMID: 35275912 PMCID: PMC8916679 DOI: 10.1371/journal.pone.0259807] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2021] [Accepted: 02/23/2022] [Indexed: 11/23/2022] Open
Abstract
Francisella tularensis is the etiologic agent of tularemia and a Tier I Select Agent. Subspecies tularensis (Type A) is the most virulent of the four subspecies and inhalation of as few as 10 cells can cause severe disease in humans. Due to its niche as a facultative intracellular pathogen, a successful tularemia vaccine must induce a robust cellular immune response, which is best achieved by a live, attenuated strain. F. tularensis strains lacking lipopolysaccharide (LPS) O-antigen are highly attenuated, but do not persist in the host long enough to induce protective immunity. Increasing the persistence of an O-antigen mutant may help stimulate protective immunity. Alginate encapsulation is frequently used with probiotics to increase persistence of bacteria within the gastrointestinal system, and was used to encapsulate the highly attenuated LVS O-antigen mutant WbtIG191V. Encapsulation with alginate followed by a poly-L-lysine/alginate coating increased survival of WbtIG191V in complement-active serum. In addition, BALB/c mice immunized intraperitoneally with encapsulated WbtIG191V combined with purified LPS survived longer than mock-immunized mice following intranasal challenge. Alginate encapsulation of the bacteria also increased antibody titers compared to non-encapsulated bacteria. These data suggest that alginate encapsulation provides a slow-release vehicle for bacterial deposits, as evidenced by the increased antibody titer and increased persistence in serum compared to freely suspended cells. Survival of mice against high-dose intranasal challenge with the LVS wildtype was similar between mice immunized within alginate capsules or with LVS, possibly due to the low number of animals used, but bacterial loads in the liver and spleen were the lowest in mice immunized with WbtIG191V and LPS in beads. However, an analysis of the immune response of surviving mice indicated that those vaccinated with the alginate vehicle upregulated cell-mediated immune pathways to a lesser extent than LVS-vaccinated mice. In summary, this vehicle, as formulated, may be more effective for pathogens that require predominately antibody-mediated immunity.
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Affiliation(s)
- Kelly C. Freudenberger Catanzaro
- Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Tech, Blacksburg, Virginia, United States of America
| | - Kevin K. Lahmers
- Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Tech, Blacksburg, Virginia, United States of America
| | - Irving C. Allen
- Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Tech, Blacksburg, Virginia, United States of America
| | - Thomas J. Inzana
- Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Tech, Blacksburg, Virginia, United States of America
- College of Veterinary Medicine, Long Island University, Brookville, New York, United States of America
- * E-mail:
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Novel Transcriptional and Translational Biomarkers of Tularemia Vaccine Efficacy in a Mouse Inhalation Model: Proof of Concept. Microorganisms 2021; 10:microorganisms10010036. [PMID: 35056485 PMCID: PMC8778127 DOI: 10.3390/microorganisms10010036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2021] [Revised: 12/15/2021] [Accepted: 12/20/2021] [Indexed: 11/18/2022] Open
Abstract
Francisella tularensis subspecies tularensis (Ftt) is extremely virulent for humans when inhaled as a small particle aerosol (<5 µm). Inhalation of ≥20 viable bacteria is sufficient to initiate infection with a mortality rate ≥30%. Consequently, in the past, Ftt became a primary candidate for biological weapons development. To counter this threat, the USA developed a live vaccine strain (LVS), that showed efficacy in humans against inhalation of virulent Ftt. However, the breakthrough dose was fairly low, and protection waned with time. These weaknesses triggered extensive research for better vaccine candidates. Previously, we showed that deleting the clpB gene from virulent Ftt strain, SCHU S4, resulted in a mutant that was significantly less virulent than LVS for mice, yet better protected them from aerosol challenge with wild-type SCHU S4. To date, comprehensive searches for correlates of protection for SCHU S4 ΔclpB among molecules that are critical signatures of cell-mediated immunity, have yielded little reward. In this study we used transcriptomics analysis to expand the potential range of molecular correlates of protection induced by vaccination with SCHU S4 ΔclpB beyond the usual candidates. The results provide proof-of-concept that unusual host responses to vaccination can potentially serve as novel efficacy biomarkers for new tularemia vaccines.
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Shoudy LE, Namjoshi P, Giordano G, Kumar S, Bowling JD, Gelhaus C, Barry EM, Hazlett AJ, Hazlett BA, Cooper KL, Pittman PR, Reed DS, Hazlett KRO. The O-Ag Antibody Response to Francisella Is Distinct in Rodents and Higher Animals and Can Serve as a Correlate of Protection. Pathogens 2021; 10:pathogens10121646. [PMID: 34959601 PMCID: PMC8704338 DOI: 10.3390/pathogens10121646] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Revised: 12/13/2021] [Accepted: 12/17/2021] [Indexed: 11/16/2022] Open
Abstract
Identifying correlates of protection (COPs) for vaccines against lethal human (Hu) pathogens, such as Francisella tularensis (Ft), is problematic, as clinical trials are currently untenable and the relevance of various animal models can be controversial. Previously, Hu trials with the live vaccine strain (LVS) demonstrated ~80% vaccine efficacy against low dose (~50 CFU) challenge; however, protection deteriorated with higher challenge doses (~2000 CFU of SchuS4) and no COPs were established. Here, we describe our efforts to develop clinically relevant, humoral COPs applicable to high-dose, aerosol challenge with S4. First, our serosurvey of LVS-vaccinated Hu and animals revealed that rabbits (Rbs), but not rodents, recapitulate the Hu O-Ag dependent Ab response to Ft. Next, we assayed Rbs immunized with distinct S4-based vaccine candidates (S4ΔclpB, S4ΔguaBA, and S4ΔaroD) and found that, across multiple vaccines, the %O-Ag dep Ab trended with vaccine efficacy. Among S4ΔguaBA-vaccinated Rbs, the %O-Ag dep Ab in pre-challenge plasma was significantly higher in survivors than in non-survivors; a cut-off of >70% O-Ag dep Ab predicted survival with high sensitivity and specificity. Finally, we found this COP in 80% of LVS-vaccinated Hu plasma samples as expected for a vaccine with 80% Hu efficacy. Collectively, the %O-Ag dep Ab response is a bona fide COP for S4ΔguaBA-vaccinated Rb and holds significant promise for guiding vaccine trials with higher animals.
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Affiliation(s)
- Lauren E. Shoudy
- Department of Regenerative and Cancer Cell Biology, Albany Medical College, Albany, NY 12208, USA; (L.E.S.); (G.G.)
| | - Prachi Namjoshi
- Department of Immunology and Microbial Disease, Albany Medical College, Albany, NY 12208, USA; (P.N.); (S.K.)
| | - Gabriela Giordano
- Department of Regenerative and Cancer Cell Biology, Albany Medical College, Albany, NY 12208, USA; (L.E.S.); (G.G.)
| | - Sudeep Kumar
- Department of Immunology and Microbial Disease, Albany Medical College, Albany, NY 12208, USA; (P.N.); (S.K.)
| | - Jennifer D. Bowling
- Center for Vaccine Research, University of Pittsburgh, Pittsburgh, PA 15261, USA; (J.D.B.); (D.S.R.)
| | | | - Eileen M. Barry
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, MD 21201, USA;
| | - Allan J. Hazlett
- Department of Philosophy, Washington University, St Louis, MO 63130, USA;
| | - Brian A. Hazlett
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI 48109, USA;
| | - Kristine L. Cooper
- Hillman Cancer Center, Biostatistics Facility, University of Pittsburgh, Pittsburgh, PA 15261, USA;
| | - Phillip R. Pittman
- U.S. Army Medical Research Institute of Infectious Diseases, Fort Detrick, Fredrick, MD 21702, USA;
| | - Douglas S. Reed
- Center for Vaccine Research, University of Pittsburgh, Pittsburgh, PA 15261, USA; (J.D.B.); (D.S.R.)
| | - Karsten R. O. Hazlett
- Department of Regenerative and Cancer Cell Biology, Albany Medical College, Albany, NY 12208, USA; (L.E.S.); (G.G.)
- Department of Immunology and Microbial Disease, Albany Medical College, Albany, NY 12208, USA; (P.N.); (S.K.)
- Correspondence: ; Tel.: +1-518-262-2338
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