scholarly journals Bacillus subtilis spore vaccines displaying protective antigen induce functional antibodies and protective potency

2020 ◽  
Author(s):  
Yeonsu Oh ◽  
Jung Ae Kim ◽  
Chang-Hwan Kim ◽  
Soo-Keun Choi ◽  
Jae-Gu Pan
Keyword(s):  
Protective Antigen ◽  
Neutralizing Antibody ◽  
Human Consumption ◽  
Antigen Delivery ◽  
Antibody Isotype ◽  
Lethal Challenge ◽  
Bacillus Subtilis Spore ◽  
Mucosal Antibody ◽  
Challenge Experiment ◽  
Functional Antibodies

Abstract Background: Bacillus anthracis is the causative agent of anthrax, a disease of both humans and various animal species, and can be used as a bioterror agent. Effective vaccines are available, but those could benefit from improvements, including increasing the immunity duration, reducing the shot frequency and adverse reactions. In addition, more sophisticated antigen delivery and potentiation systems are urgently required. The protective antigen (PA), one of three major virulence factors associated with anthrax was displayed on the surface of Bacillus subtilis spores, which is a vaccine production host and delivery vector with several advantages such as a low production cost, straightforward administration as it is safe for human consumption and the particulate adjuvanticity. Mice were immunized orally (PO), intranasally (IN), sublingually (SL) or intraperitoneally (IP) with the PA displaying probiotic spore vaccine. Clinical observation, serological analysis and challenge experiment were conducted to investigate the safety and efficacy of the vaccine. Results: A/J mice immunized with the PA spore vaccine via PO, IN, SL, and IP were observed to have increased levels of active antibody titer, isotype profiles and toxin neutralizing antibody in sera, and IgA in saliva. The immunized mice were demonstrated to raise protective immunity against the challenge with lethal B. anthracis spores. Conclusions: In this study, we developed a B. subtilis spore vaccine that displays the PA on its surface and showed that the PA-displaying spore vaccine was able to confer active immunity to a murine model based on the results of antibody isotype titration, mucosal antibody identification, and a lethal challenge experiment.

scholarly journals Bacillus subtilis spore vaccines displaying protective antigen induce functional antibodies and protective potency

2020 ◽  
Author(s):  
Yeonsu Oh ◽  
Jung Ae Kim ◽  
Chang-Hwan Kim ◽  
Soo-Keun Choi ◽  
Jae-Gu Pan
Keyword(s):  
Protective Antigen ◽  
Neutralizing Antibody ◽  
Human Consumption ◽  
Antigen Delivery ◽  
Antibody Isotype ◽  
Lethal Challenge ◽  
Bacillus Subtilis Spore ◽  
Mucosal Antibody ◽  
Challenge Experiment ◽  
Functional Antibodies

Abstract Background: Bacillus anthracis is the causative agent of anthrax, a disease of both humans and various animal species, and can be used as a bioterror agent. Effective vaccines are available, but those could benefit from improvements, including increasing the immunity duration, reducing the shot frequency and adverse reactions. In addition, more sophisticated antigen delivery and potentiation systems are urgently required. The protective antigen (PA), one of three major virulence factors associated with anthrax was displayed on the surface of Bacillus subtilis spores, which is a vaccine production host and delivery vector with several advantages such as a low production cost, straightforward administration as it is safe for human consumption and the particulate adjuvanticity. Mice were immunized orally (PO), intranasally (IN), sublingually (SL) or intraperitoneally (IP) with the PA displaying probiotic spore vaccine. Clinical observation, serological analysis and challenge experiment were conducted to investigate the safety and efficacy of the vaccine. Results: A/J mice immunized with the PA spore vaccine via PO, IN, SL, and IP were observed to have increased levels of active antibody titer, isotype profiles and toxin neutralizing antibody in sera, and IgA in saliva. The immunized mice were demonstrated to raise protective immunity against the challenge with lethal B. anthracis spores. Conclusions: In this study, we developed a B. subtilis spore vaccine that displays the PA on its surface and showed that the PA-displaying spore vaccine was able to confer active immunity to a murine model based on the results of antibody isotype titration, mucosal antibody identification, and a lethal challenge experiment.

scholarly journals Bacillus subtilis spore vaccines displaying protective antigen induce functional antibodies and protective potency

2020 ◽  
Author(s):  
Yeonsu Oh ◽  
Jung Ae Kim ◽  
Chang-Hwan Kim ◽  
Soo-Keun Choi ◽  
Jae-Gu Pan
Keyword(s):  
Protective Antigen ◽  
Neutralizing Antibody ◽  
Human Consumption ◽  
Antigen Delivery ◽  
Antibody Isotype ◽  
Lethal Challenge ◽  
Bacillus Subtilis Spore ◽  
Mucosal Antibody ◽  
Challenge Experiment ◽  
Functional Antibodies

Abstract Background: Bacillus anthracis is the causative agent of anthrax, a disease of both humans and various animal species, and can be used as a bioterror agent. Effective vaccines are available, but those could benefit from improvements, including increasing the immunity duration, reducing the shot frequency and adverse reactions. In addition, more sophisticated antigen delivery and potentiation systems are urgently required. The protective antigen (PA), one of three major virulence factors associated with anthrax was displayed on the surface of Bacillus subtilis spores, which is a vaccine production host and delivery vector with several advantages such as a low production cost, straightforward administration as it is safe for human consumption and the particulate adjuvanticity. Mice were immunized orally (PO), intranasally (IN), sublingually (SL) or intraperitoneally (IP) with the PA displaying probiotic spore vaccine. Clinical observation, serological analysis and challenge experiment were conducted to investigate the safety and efficacy of the vaccine. Results: A/J mice immunized with the PA spore vaccine via PO, IN, SL, and IP were observed to have increased levels of active antibody titer, isotype profiles and toxin neutralizing antibody in sera, and IgA in saliva. The immunized mice were demonstrated to raise protective immunity against the challenge with lethal B. anthracis spores. Conclusions: In this study, we developed a B. subtilis spore vaccine that displays the PA on its surface and showed that the PA-displaying spore vaccine was able to confer active immunity to a murine model based on the results of antibody isotype titration, mucosal antibody identification, and a lethal challenge experiment.

scholarly journals Search for Correlates of Protective Immunity Conferred by Anthrax Vaccine

2001 ◽  
Vol 69 (5) ◽  
pp. 2888-2893 ◽  
Author(s):  
Shaul Reuveny ◽  
Moshe D. White ◽  
Yaakov Y. Adar ◽  
Yaron Kafri ◽  
Zeev Altboum ◽  
...  
Keyword(s):  
Antibody Titer ◽  
Neutralizing Antibodies ◽  
Protective Immunity ◽  
Protective Antigen ◽  
Surrogate Marker ◽  
Neutralizing Antibody ◽  
Enzyme Linked Immunosorbent Assay ◽  
Lethal Challenge ◽  
Anthrax Spores ◽  
Antibody Titers

ABSTRACT Vaccination by anthrax protective antigen (PA)-based vaccines requires multiple immunization, underlying the need to develop more efficacious vaccines or alternative vaccination regimens. In spite of the vast use of PA-based vaccines, the definition of a marker for protective immunity is still lacking. Here we describe studies designed to help define such markers. To this end we have immunized guinea pigs by different methods and monitored the immune response and the corresponding extent of protection against a lethal challenge with anthrax spores. Active immunization was performed by a single injection using one of two methods: (i) vaccination with decreasing amounts of PA and (ii) vaccination with constant amounts of PA that had been thermally inactivated for increasing periods. In both studies a direct correlation between survival and neutralizing-antibody titer was found (r 2 = 0.92 and 0.95, respectively). Most significantly, in the two protocols a similar neutralizing-antibody titer range provided 50% protection. Furthermore, in a complementary study involving passive transfer of PA hyperimmune sera to naive animals, a similar correlation between neutralizing-antibody titers and protection was found. In all three immunization studies, neutralization titers of at least 300 were sufficient to confer protection against a dose of 40 50% lethal doses (LD50) of virulent anthrax spores of the Vollum strain. Such consistency in the correlation of protective immunity with anti-PA antibody titers was not observed for antibody titers determined by an enzyme-linked immunosorbent assay. Taken together, these results clearly demonstrate that neutralizing antibodies to PA constitute a major component of the protective immunity against anthrax and suggest that this parameter could be used as a surrogate marker for protection.

scholarly journals Detoxified Lethal Toxin as a Potential Mucosal Vaccine against Anthrax

2008 ◽  
Vol 15 (4) ◽  
pp. 612-616 ◽  
Author(s):  
Qingfu Xu ◽  
Mingtao Zeng
Keyword(s):  
Protective Antigen ◽  
Lethal Factor ◽  
Lethal Dose ◽  
Neutralizing Antibody ◽  
Lethal Toxin ◽  
Antibody Responses ◽  
Mucosal Vaccine ◽  
Enhancement Effect ◽  
Anthrax Lethal Toxin ◽  
Mucosal Antibody

ABSTRACT The nontoxic mutant lethal factor (mLF; which has the E687C substitution) and functional protective antigen (PA63) of Bacillus anthracis were evaluated for their use as mucosal vaccines against anthrax in A/J mice. Intranasal vaccination of three doses of 30 μg of mLF or 60 μg of PA63 elicited significant serum and mucosal antibody responses, with anthrax lethal toxin-neutralizing titers of 40 and 60 in immune sera, respectively. However, only 30% and 60% of the vaccinated animals in the two groups could survive a challenge with 100 times the 50% lethal dose of B. anthracis Sterne spores, respectively. In contrast, vaccination with three doses of the combination of 30 μg of mLF and 60 μg of PA63, the detoxified lethal toxin, elicited antibody responses against LF and PA significantly higher than those elicited after vaccination with mLF or PA63 individually by use of the same dose and schedule. Vaccination with the detoxified lethal toxin resulted in significantly higher lethal toxin-neutralizing antibody titers in sera (titer, 90). Animals vaccinated with three doses of the detoxified lethal toxin were completely protected against the spore challenge. The data suggest that mLF and PA63 have a mutual enhancement effect for evoking systemic and mucosal immune responses and that the detoxified lethal toxin can be used as an efficient mucosal vaccine against anthrax.

scholarly journals Protection against Anthrax Lethal Toxin Challenge by Genetic Immunization with a Plasmid Encoding the Lethal Factor Protein

2001 ◽  
Vol 69 (7) ◽  
pp. 4509-4515 ◽  
Author(s):  
Brian M. Price ◽  
Adriane L. Liner ◽  
Sukjoon Park ◽  
Stephen H. Leppla ◽  
Alfred Mateczun ◽  
...  
Keyword(s):  
Plasmid Dna ◽  
Expression Vector ◽  
Protective Antigen ◽  
Lethal Factor ◽  
Lethal Toxin ◽  
Biologically Active ◽  
Gene Gun ◽  
Anthrax Lethal Toxin ◽  
Antibody Isotype ◽  
Lethal Challenge

ABSTRACT The ability of genetic vaccination to protect against a lethal challenge of anthrax toxin was evaluated. BALB/c mice were immunized via gene gun inoculation with eucaryotic expression vector plasmids encoding either a fragment of the protective antigen (PA) or a fragment of lethal factor (LF). Plasmid pCLF4 contains the N-terminal region (amino acids [aa] 10 to 254) of Bacillus anthracis LF cloned into the pCI expression plasmid. Plasmid pCPA contains a biologically active portion (aa 175 to 764) ofB. anthracis PA cloned into the pCI expression vector. One-micrometer-diameter gold particles were coated with plasmid pCLF4 or pCPA or a 1:1 mixture of both and injected into mice via gene gun (1 μg of plasmid DNA/injection) three times at 2-week intervals. Sera were collected and analyzed for antibody titer as well as antibody isotype. Significantly, titers of antibody to both PA and LF from mice immunized with the combination of pCPA and pCLF4 were four to five times greater than titers from mice immunized with either gene alone. Two weeks following the third and final plasmid DNA boost, all mice were challenged with 5 50% lethal doses of lethal toxin (PA plus LF) injected intravenously into the tail vein. All mice immunized with pCLF4, pCPA, or the combination of both survived the challenge, whereas all unimmunized mice did not survive. These results demonstrate that DNA-based immunization alone can provide protection against a lethal toxin challenge and that DNA immunization against the LF antigen alone provides complete protection.

scholarly journals The immune landscape of IgA induction in the gut

2021 ◽  
Author(s):  
Claudia Seikrit ◽  
Oliver Pabst
Keyword(s):  
Protective Immunity ◽  
Immunoglobulin A ◽  
Antibody Responses ◽  
Dark Side ◽  
Secretory Immunoglobulin A ◽  
Antibody Isotype ◽  
Mucosal Antibody ◽  
Key Concepts ◽  
Basic Understanding ◽  
Secretory Immunoglobulin

AbstractAntibodies are key elements of protective immunity. In the mucosal immune system in particular, secretory immunoglobulin A (SIgA), the most abundantly produced antibody isotype, protects against infections, shields the mucosal surface from toxins and environmental factors, and regulates immune homeostasis and a peaceful coexistence with our microbiota. However, the dark side of IgA biology promotes the formation of immune complexes and provokes pathologies, e.g., IgA nephropathy (IgAN). The precise mechanisms of how IgA responses become deregulated and pathogenic in IgAN remain unresolved. Yet, as the field of microbiota research moved into the limelight, our basic understanding of IgA biology has been taking a leap forward. Here, we discuss the structure of IgA, the anatomical and cellular foundation of mucosal antibody responses, and current concepts of how we envision the interaction of SIgA and the microbiota. We center on key concepts in the field while taking account of both historic findings and exciting new observations to provide a comprehensive groundwork for the understanding of IgA biology from the perspective of a mucosal immunologist.

scholarly journals A Chimeric Protein That Functions as both an Anthrax Dual-Target Antitoxin and a Trivalent Vaccine

2010 ◽  
Vol 54 (11) ◽  
pp. 4750-4757 ◽  
Author(s):  
Gaobing Wu ◽  
Yuzhi Hong ◽  
Aizhen Guo ◽  
Chunfang Feng ◽  
Sha Cao ◽  
...  
Keyword(s):  
Protective Antigen ◽  
Vaccine Candidate ◽  
Lethal Factor ◽  
Lethal Dose ◽  
Chimeric Protein ◽  
Dominant Negative ◽  
Lethal Challenge ◽  
Edema Factor ◽  
Trivalent Vaccine

ABSTRACT Effective measures for the prophylaxis and treatment of anthrax are still required for counteracting the threat posed by inhalation anthrax. In this study, we first demonstrated that the chimeric protein LFn-PA, created by fusing the protective antigen (PA)-binding domain of lethal factor (LFn) to PA, retained the functions of the respective molecules. On the basis of this observation, we attempted to develop an antitoxin that targets the binding of lethal factor (LF) and/or edema factor (EF) to PA and the transportation of LF/EF. Therefore, we replaced PA in LFn-PA with a dominant-negative inhibitory PA (DPA), i.e., PAF427D. In in vitro models of anthrax intoxication, the LFn-DPA chimera showed 3-fold and 2-fold higher potencies than DPA in protecting sensitive cells against anthrax lethal toxin (LeTx) and edema toxin (EdTx), respectively. In animal models, LFn-DPA exhibited strong potency in rescuing mice from lethal challenge with LeTx. We also evaluated the immunogenicity and immunoprotective efficacy of LFn-DPA as an anthrax vaccine candidate. In comparison with recombinant PA, LFn-DPA induced significantly higher levels of the anti-PA immune response. Moreover, LFn-DPA elicited an anti-LF antibody response that could cross-react with EF. Mice immunized with LFn-DPA tolerated a LeTx challenge that was 5 times its 50% lethal dose. Thus, LFn-DPA represents a highly effective trivalent vaccine candidate for both preexposure and postexposure vaccination. Overall, we have developed a novel and dually functional reagent for the prophylaxis and treatment of anthrax.

scholarly journals Efficacy of a Vaccine Based on Protective Antigen and Killed Spores against Experimental Inhalational Anthrax

2008 ◽  
Vol 77 (3) ◽  
pp. 1197-1207 ◽  
Author(s):  
Yves P. Gauthier ◽  
Jean-Nicolas Tournier ◽  
Jean-Charles Paucod ◽  
Jean-Philippe Corre ◽  
Michèle Mock ◽  
...  
Keyword(s):  
Guinea Pigs ◽  
Protective Immunity ◽  
Protective Antigen ◽  
Virulent Strain ◽  
Neutralizing Antibody ◽  
Cutaneous Anthrax ◽  
Anthrax Vaccines ◽  
Mucosal Secretions ◽  
Highly Virulent ◽  
Lethal Doses

ABSTRACTProtective antigen (PA)-based anthrax vaccines acting on toxins are less effective than live attenuated vaccines, suggesting that additional antigens may contribute to protective immunity. Several reports indicate that capsule or spore-associated antigens may enhance the protection afforded by PA. Addition of formaldehyde-inactivated spores (FIS) to PA (PA-FIS) elicits total protection against cutaneous anthrax. Nevertheless, vaccines that are effective against cutaneous anthrax may not be so against inhalational anthrax. The aim of this work was to optimize immunization with PA-FIS and to assess vaccine efficacy against inhalational anthrax. We assessed the immune response to recombinant anthrax PA fromBacillus anthracis(rPA)-FIS administered by various immunization protocols and the protection provided to mice and guinea pigs infected through the respiratory route with spores of a virulent strain ofB. anthracis. Combined subcutaneous plus intranasal immunization of mice yielded a mucosal immunoglobulin G response to rPA that was more than 20 times higher than that in lung mucosal secretions after subcutaneous vaccination. The titers of toxin-neutralizing antibody and antispore antibody were also significantly higher: nine and eight times higher, respectively. The optimized immunization elicited total protection of mice intranasally infected with the virulentB. anthracisstrain 17JB. Guinea pigs were fully protected, both against an intranasal challenge with 100 50% lethal doses (LD50) and against an aerosol with 75 LD50of spores of the highly virulent strain 9602. Conversely, immunization with PA alone did not elicit protection. These results demonstrate that the association of PA and spores is very much more effective than PA alone against experimental inhalational anthrax.

scholarly journals Analysis of Defined Combinations of Monoclonal Antibodies in Anthrax Toxin Neutralization Assays and Their Synergistic Action

2012 ◽  
Vol 19 (5) ◽  
pp. 731-739 ◽  
Author(s):  
Miriam M. Ngundi ◽  
Bruce D. Meade ◽  
Stephen F. Little ◽  
Conrad P. Quinn ◽  
Cindi R. Corbett ◽  
...  
Keyword(s):  
Cell Culture ◽  
Monoclonal Antibodies ◽  
Protective Antigen ◽  
Neutralizing Antibody ◽  
Synergistic Action ◽  
Anthrax Toxin ◽  
Content Type ◽  
Antagonistic Effects ◽  
Antibody Interactions ◽  
New Vaccines

ABSTRACTAntibodies against the protective antigen (PA) component of anthrax toxin play an important role in protection against disease caused byBacillus anthracis. In this study, we examined defined combinations of PA-specific monoclonal antibodies for their ability to neutralize anthrax toxin in cell culture assays. We observed additive, synergistic, and antagonistic effects of the antibodies depending on the specific antibody combination examined and the specific assay used. Synergistic toxin-neutralizing antibody interactions were examined in more detail. We found that one mechanism that can lead to antibody synergy is the bridging of PA monomers by one antibody, with resultant bivalent binding of the second antibody. These results may aid in optimal design of new vaccines and antibody therapies against anthrax.

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