scholarly journals Subunit Vaccines Using TLR Triagonist Combination Adjuvants Provide Protection Against Coxiella burnetii While Minimizing Reactogenic Responses

2021 ◽  
Vol 12 ◽  
Author(s):  
Alycia P. Fratzke ◽  
Sharon Jan ◽  
Jiin Felgner ◽  
Li Liang ◽  
Rie Nakajima ◽  
...  
Keyword(s):  
Coxiella Burnetii ◽  
Q Fever ◽  
Protective Efficacy ◽  
Cell Vaccine ◽  
Protein Subunit ◽  
Subunit Vaccines ◽  
Whole Cell ◽  
Vaccine Candidates ◽  
Route Of Transmission ◽  
Whole Cell Vaccine

Q fever is caused by the obligate intracellular bacterium, Coxiella burnetii, a designated potential agent of bioterrorism because of its route of transmission, resistance to disinfectants, and low infectious dose. The only vaccine licensed for human use is Q-VAX® (Seqirus, licensed in Australia), a formalin-inactivated whole-cell vaccine, which produces severe local and systemic reactogenic responses in previously sensitized individuals. Accordingly, the U.S. Food and Drug Administration and other regulatory bodies around the world, have been reluctant to approve Q-VAX for widespread use. To obviate these adverse reactions, we prepared recombinant protein subunit vaccine candidates containing purified CBU1910, CBU0307, CBU0545, CBU0612, CBU0891, and CBU1398 proteins and TLR triagonist adjuvants. TLR triagonist adjuvants combine different TLR agonists to enhance immune responses to vaccine antigens. We tested both the protective efficacy and reactogenicity of our vaccine candidates in Hartley guinea pigs using intratracheal infection with live C. burnetii. While all of our candidates showed varying degrees of protection during challenge, local reactogenic responses were significantly reduced for one of our vaccine candidates when compared with a formalin-inactivated whole-cell vaccine. Our findings show that subunit vaccines combined with novel TLR triagonist adjuvants can generate protective immunity to C. burnetii infection while reducing reactogenic responses.

scholarly journals Immunoreactive Coxiella burnetii Nine Mile proteins separated by 2D electrophoresis and identified by tandem mass spectrometry

Microbiology ◽  
2011 ◽  
Vol 157 (2) ◽  
pp. 526-542 ◽  
Author(s):  
James R. Deringer ◽  
Chen Chen ◽  
James E. Samuel ◽  
Wendy C. Brown
Keyword(s):  
T Cell ◽  
Guinea Pig ◽  
Coxiella Burnetii ◽  
Guinea Pigs ◽  
Subunit Vaccine ◽  
Q Fever ◽  
Cell Vaccine ◽  
2D Electrophoresis ◽  
Whole Cell ◽  
Vaccine Candidates

Coxiella burnetii is a Gram-negative obligate intracellular pathogen and the causative agent of Q fever in humans. Q fever causes acute flu-like symptoms and may develop into a chronic disease leading to endocarditis. Its potential as a bioweapon has led to its classification as a category B select agent. An effective inactivated whole-cell vaccine (WCV) currently exists but causes severe granulomatous/necrotizing reactions in individuals with prior exposure, and is not licensed for use in most countries. Current efforts to reduce or eliminate the deleterious reactions associated with WCVs have focused on identifying potential subunit vaccine candidates. Both humoral and T cell-mediated responses are required for protection in animal models. In this study, nine novel immunogenic C. burnetii proteins were identified in extracted whole-cell lysates using 2D electrophoresis, immunoblotting with immune guinea pig sera, and tandem MS. The immunogenic C. burnetii proteins elicited antigen-specific IgG in guinea pigs vaccinated with whole-cell killed Nine Mile phase I vaccine, suggesting a T cell-dependent response. Eleven additional proteins previously shown to react with immune human sera were also antigenic in guinea pigs, showing the relevance of the guinea pig immunization model for antigen discovery. The antigens described here warrant further investigation to validate their potential use as subunit vaccine candidates.

scholarly journals Contributions of lipopolysaccharide and the type IVB secretion system to Coxiella burnetii vaccine efficacy and reactogenicity

npj Vaccines ◽  
2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Carrie M. Long ◽  
Paul A. Beare ◽  
Diane C. Cockrell ◽  
Jonathan Fintzi ◽  
Mahelat Tesfamariam ◽  
...  
Keyword(s):  
Phase I ◽  
Coxiella Burnetii ◽  
Vaccine Efficacy ◽  
Q Fever ◽  
Secretion System ◽  
Cell Vaccine ◽  
Post Vaccination ◽  
Whole Cell Vaccine ◽  
Type Ivb Secretion ◽  
Type Ivb Secretion System

AbstractCoxiella burnetii is the bacterial causative agent of the zoonosis Q fever. The current human Q fever vaccine, Q-VAX®, is a fixed, whole cell vaccine (WCV) licensed solely for use in Australia. C. burnetii WCV administration is associated with a dermal hypersensitivity reaction in people with pre-existing immunity to C. burnetii, limiting wider use. Consequently, a less reactogenic vaccine is needed. Here, we investigated contributions of the C. burnetii Dot/Icm type IVB secretion system (T4BSS) and lipopolysaccharide (LPS) in protection and reactogenicity of fixed WCVs. A 32.5 kb region containing 23 dot/icm genes was deleted in the virulent Nine Mile phase I (NMI) strain and the resulting mutant was evaluated in guinea pig models of C. burnetii infection, vaccination-challenge, and post-vaccination hypersensitivity. The NMI ∆dot/icm strain was avirulent, protective as a WCV against a robust C. burnetii challenge, and displayed potentially altered reactogenicity compared to NMI. Nine Mile phase II (NMII) strains of C. burnetii that produce rough LPS, were similarly tested. NMI was significantly more protective than NMII as a WCV; however, both vaccines exhibited similar reactogenicity. Collectively, our results indicate that, like phase I LPS, the T4BSS is required for full virulence by C. burnetii. Conversely, unlike phase I LPS, the T4BSS is not required for vaccine-induced protection. LPS length does not appear to contribute to reactogenicity while the T4BSS may contribute to this response. NMI ∆dot/icm represents an avirulent phase I strain with full vaccine efficacy, illustrating the potential of genetically modified C. burnetii as improved WCVs.

scholarly journals Coxiella burnetii Whole Cell Vaccine Produces a Th1 Delayed-Type Hypersensitivity Response in a Novel Sensitized Mouse Model

2021 ◽  
Vol 12 ◽  
Author(s):  
Alycia P. Fratzke ◽  
Anthony E. Gregory ◽  
Erin J. van Schaik ◽  
James E. Samuel
Keyword(s):  
T Cells ◽  
Coxiella Burnetii ◽  
Cd4 T Cells ◽  
Delayed Type Hypersensitivity ◽  
Cell Vaccine ◽  
Mouse Strains ◽  
Vaccination Site ◽  
Whole Cell ◽  
Cellular Analysis ◽  
Whole Cell Vaccine

Q-VAX®, a whole cell, formalin-inactivated vaccine, is the only vaccine licensed for human use to protect against Coxiella burnetii, the cause of Q fever. Although this vaccine provides long-term protection, local and systemic reactogenic responses are common in previously sensitized individuals which prevents its use outside of Australia. Despite the importance of preventing these adverse reactions to develop widely accepted, novel vaccines against C. burnetii, little is understood about the underlying cellular mechanisms. This is mostly attributed to the use of a guinea pig reactogenicity model where complex cellular analysis is limited. To address this, we compared three different mouse strains develop a model of C. burnetii whole cell vaccine reactogenic responses. SKH1 and C57Bl/6, but not BALBc mice, develop local granulomatous reactions after either infection- or vaccine-induced sensitization. We evaluated local and systemic responses by measuring T cell populations from the vaccination site and spleen during elicitation using flow cytometry. Local reaction sites showed influx of IFNγ+ and IL17a+ CD4 T cells in sensitized mice compared with controls and a reduction in IL4+ CD4 T cells. Additionally, sensitized mice showed a systemic response to elicitation by an increase in IFNγ+ and IL17a+ CD4 T cells in the spleen. These results indicate that local and systemic C. burnetii reactogenic responses are consistent with a Th1 delayed-type hypersensitivity. Our experiments provide insights into the pathophysiology of C. burnetii whole cell vaccine reactogenicity and demonstrate that C57Bl/6 and SKH1 mice can provide a valuable model for evaluating the reactogenicity of novel C. burnetii vaccine candidates.

scholarly journals Chemokine Receptor 7 Is Essential for Coxiella burnetii Whole-Cell Vaccine-Induced Cellular Immunity but Dispensable for Vaccine-Mediated Protective Immunity

2019 ◽  
Vol 220 (4) ◽  
pp. 624-634
Author(s):  
Chen Chen ◽  
Erin J van Schaik ◽  
Anthony E Gregory ◽  
Adam Vigil ◽  
Phillip L Felgner ◽  
...  
Keyword(s):  
Coxiella Burnetii ◽  
Cellular Immunity ◽  
Protective Immunity ◽  
Cell Vaccine ◽  
Specific Antibody Response ◽  
Whole Cell ◽  
Humoral Immune ◽  
Whole Cell Vaccine ◽  
Secondary Lymphoid Organs ◽  
Dc Maturation

Abstract Background Protective immunity against Coxiella burnetii infection is conferred by vaccination with virulent (PI-WCV), but not avirulent (PII-WCV) whole-cell inactivated bacterium. The only well-characterized antigenic difference between virulent and avirulent C. burnetii is they have smooth and rough lipopolysaccharide (LPS), respectively. Methods Mice were vaccinated with PI-WCV and PII-WCV. Humoral and cellular responses were evaluated using protein chip microarrays and ELISpots, respectively. Dendritic cell (DC) maturation after stimulation with PI-WVC and PII-WVC was evaluated using flow cytometry. Vaccine-challenge studies were performed to validate the importance of the receptor CCR7. Results Other than specific antibody response to PI-LPS, similar antibody profiles were observed but IgG titers were significantly higher after vaccination with PI-WCV. Furthermore, higher frequency of antigen-specific CD4+ T cells was detected in mice immunized with PI-WCV. PI-WCV–stimulated DCs displayed significantly higher levels of CCR7 and migratory ability to secondary lymphoid organs. Challenge-protection studies in wild-type and CCR7-deficient mice confirmed that CCR7 is critical for PI-WCV–induced cellular immunity. Conclusions PI-WVC stimulates protective immunity to C. burnetii in mice through stimulation of migratory behavior in DCs for protective cellular immunity. Additionally, the humoral immune response to LPS is an important component of protective immunity.

scholarly journals TH17-Mediated Protection against Pneumococcal Carriage by a Whole-Cell Vaccine Is Dependent on Toll-Like Receptor 2 and Surface Lipoproteins

2015 ◽  
Vol 22 (8) ◽  
pp. 909-916 ◽  
Author(s):  
K. Moffitt ◽  
A. Howard ◽  
S. Martin ◽  
E. Cheung ◽  
M. Herd ◽  
...  
Keyword(s):  
Vaccine Development ◽  
Protective Efficacy ◽  
Cell Vaccine ◽  
Membrane Localization ◽  
Toll Like Receptor ◽  
Gene Encoding ◽  
Whole Cell ◽  
Interleukin 17A ◽  
Whole Cell Vaccine ◽  
Toll Like Receptor 2

ABSTRACTA pneumococcal whole-cell vaccine (WCV) confers TH17-mediated immunogenicity and reduces nasopharyngeal (NP) carriage in mice. Activation of Toll-like receptor 2 (TLR2) has been shown to be important for generating TH17 responses, and several lipidated pneumococcal proteins have TLR2-activating properties. Here we investigated the roles of TLR2 and lipidation of proteins in WCV-induced interleukin-17A (IL-17A) responses and protection against NP carriage. Immunization ofTlr2−/−mice with WCV conferred significantly lower IL-17A levels and reduced protection against NP carriage, compared to wild-type (WT) mice, suggesting that host TLR2 engagement is required for effective immunity and protection elicited by WCV immunization. Using a WCV with deletion oflgt, the gene encoding the enzyme required for lipidation and membrane attachment of prolipoproteins, we show that lipidation and membrane localization of these proteins are critical for the immunogenicity and protective efficacy of the WCV. To evaluate the roles of diacylglyceryl transferase (Lgt)-mediated processes in the recall of WCV-induced protective responses, we colonized WCV-immunized animals with a strain in whichlgtwas deleted. WCV-immunized animals still had significantly reduced colonization burdens, compared to control animals, which suggests that lipidation and membrane localization of pneumococcal prolipoproteins are less critical for the recall of the immune responses elicited by WCV immunization than for the priming of such responses. Elucidation of underlying immune mechanisms and the optimal characteristics of WCV formulations can help guide vaccine development and enhance our understanding of host-pneumococcus interactions.

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