Effect of Anthrax Immune Globulin on Response to BioThrax (Anthrax Vaccine Adsorbed) in New Zealand White Rabbits

ABSTRACTDevelopment of anthrax countermeasures that may be used concomitantly in a postexposure setting requires an understanding of the interaction between these products. Anthrax immune globulin intravenous (AIGIV) is a candidate immunotherapeutic that contains neutralizing antibodies against protective antigen (PA), a component of anthrax toxins. We evaluated the interaction between AIGIV and BioThrax (anthrax vaccine adsorbed) in rabbits. While pharmacokinetics of AIGIV were not altered by vaccination, the vaccine-induced immune response was abrogated in AIGIV-treated animals.

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Binding of the von Willebrand Factor A Domain of Capillary Morphogenesis Protein 2 to Anthrax Protective Antigen Vaccine Reduces Immunogenicity in Mice

mSphere ◽

10.1128/msphere.00556-19 ◽

2020 ◽

Vol 5 (1) ◽

Author(s):

Fabiana Freire Mendes de Oliveira ◽

Sireesha Mamillapalli ◽

Srinivas Gonti ◽

Robert N. Brey ◽

Han Li ◽

...

Keyword(s):

Immune Response ◽

Von Willebrand Factor ◽

Neutralizing Antibodies ◽

Protective Antigen ◽

Antibody Responses ◽

Anthrax Toxin ◽

Anthrax Vaccine ◽

Capillary Morphogenesis ◽

Von Willebrand ◽

Willebrand Factor

ABSTRACT Protective antigen (PA) is a component of anthrax toxin that can elicit toxin-neutralizing antibody responses. PA is also the major antigen in the current vaccine to prevent anthrax, but stability problems with recombinant proteins have complicated the development of new vaccines containing recombinant PA. The relationship between antigen physical stability and immunogenicity is poorly understood, but there are theoretical reasons to think that this parameter can affect immune responses. We investigated the immunogenicity of anthrax PA, in the presence and absence of the soluble von Willebrand factor A domain of the human form of receptor capillary morphogenesis protein 2 (sCMG2), to elicit antibodies to PA in BALB/c mice. Prior studies showed that sCMG2 stabilizes the 83-kDa PA structure to pH, chemical denaturants, temperature, and proteolysis and slows the hydrogen-deuterium exchange rate of histidine residues far from the binding interface. In contrast to a vaccine containing PA without adjuvant, we found that mice immunized with PA in stable complex with sCMG2 showed markedly reduced antibody responses to PA, including toxin-neutralizing antibodies and antibodies to domain 4, which correlated with fewer toxin-neutralizing antibodies. In contrast, mice immunized with PA in concert with a nonbinding mutant of sCMG2 (D50A) showed anti-PA antibody responses similar to those observed with PA alone. Our results suggest that addition of sCMG2 to a PA vaccine formulation is likely to result in a significantly diminished immune response, but we discuss the multitude of factors that could contribute to reduced immunogenicity. IMPORTANCE The anthrax toxin PA is the major immunogen in the current anthrax vaccine (anthrax vaccine adsorbed). Improving the anthrax vaccine for avoidance of a cold chain necessitates improvements in the thermodynamic stability of PA. We address how stabilizing PA using sCMG2 affects PA immunogenicity in BALB/c mice. Although the stability of PA is increased by binding to sCMG2, PA immunogenicity is decreased. This study emphasizes that, while binding of a ligand retains or improves conformational stability without affecting the native sequence, epitope recognition or processing may be affected, abrogating an effective immune response.

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Ocular Tolerability and Immune Response to Corneal Intrastromal AAV-IDUA Gene Therapy in New Zealand White Rabbits

Molecular Therapy — Methods & Clinical Development ◽

10.1016/j.omtm.2020.05.014 ◽

2020 ◽

Vol 18 ◽

pp. 24-32 ◽

Cited By ~ 1

Author(s):

Liujiang Song ◽

Jacquelyn J. Bower ◽

Telmo Llanga ◽

Jacklyn H. Salmon ◽

Matthew L. Hirsch ◽

...

Keyword(s):

Gene Therapy ◽

Immune Response ◽

New Zealand ◽

New Zealand White Rabbits ◽

Idua Gene ◽

Ocular Tolerability

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Vaccination of Rhesus Macaques with the Anthrax Vaccine Adsorbed Vaccine Produces a Serum Antibody Response That Effectively Neutralizes Receptor-Bound Protective Antigen In Vitro

Clinical and Vaccine Immunology ◽

10.1128/cvi.00174-10 ◽

2010 ◽

Vol 17 (11) ◽

pp. 1753-1762 ◽

Cited By ~ 8

Author(s):

Kristin H. Clement ◽

Thomas L. Rudge ◽

Heather J. Mayfield ◽

Lena A. Carlton ◽

Arelis Hester ◽

...

Keyword(s):

Cell Surface ◽

Neutralizing Antibodies ◽

Protective Antigen ◽

Rhesus Macaques ◽

Lethal Factor ◽

Serum Antibody ◽

Target Cells ◽

Furin Cleavage ◽

Anthrax Vaccine

ABSTRACT Anthrax toxin (ATx) is composed of the binary exotoxins lethal toxin (LTx) and edema toxin (ETx). They have separate effector proteins (edema factor and lethal factor) but have the same binding protein, protective antigen (PA). PA is the primary immunogen in the current licensed vaccine anthrax vaccine adsorbed (AVA [BioThrax]). AVA confers protective immunity by stimulating production of ATx-neutralizing antibodies, which could block the intoxication process at several steps (binding of PA to the target cell surface, furin cleavage, toxin complex formation, and binding/translocation of ATx into the cell). To evaluate ATx neutralization by anti-AVA antibodies, we developed two low-temperature LTx neutralization activity (TNA) assays that distinguish antibody blocking before and after binding of PA to target cells (noncomplexed [NC] and receptor-bound [RB] TNA assays). These assays were used to investigate anti-PA antibody responses in AVA-vaccinated rhesus macaques (Macaca mulatta) that survived an aerosol challenge with Bacillus anthracis Ames spores. Results showed that macaque anti-AVA sera neutralized LTx in vitro, even when PA was prebound to cells. Neutralization titers in surviving versus nonsurviving animals and between prechallenge and postchallenge activities were highly correlated. These data demonstrate that AVA stimulates a myriad of antibodies that recognize multiple neutralizing epitopes and confirm that change, loss, or occlusion of epitopes after PA is processed from PA83 to PA63 at the cell surface does not significantly affect in vitro neutralizing efficacy. Furthermore, these data support the idea that the full-length PA83 monomer is an appropriate immunogen for inclusion in next-generation anthrax vaccines.

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Progress towards the Development of a NEAT Vaccine for Anthrax II: Immunogen Specificity and Alum Effectiveness in an Inhalational Model

Infection and Immunity ◽

10.1128/iai.00082-20 ◽

2020 ◽

Vol 88 (8) ◽

Cited By ~ 1

Author(s):

Joseph Jelinski ◽

Austen Terwilliger ◽

Sabrina Green ◽

Anthony Maresso

Keyword(s):

Neutralizing Antibodies ◽

Protective Antigen ◽

Anthrax Toxin ◽

Cell Binding ◽

Lethal Challenge ◽

Anthrax Vaccine ◽

Content Type ◽

Heme Transport ◽

Bacillus Spores ◽

Culture Supernatants

ABSTRACT Bacillus anthracis is the causative agent of anthrax disease, presents with high mortality, and has been at the center of bioweapon efforts. The only currently U.S. FDA-approved vaccine to prevent anthrax in humans is anthrax vaccine adsorbed (AVA), which is protective in several animal models and induces neutralizing antibodies against protective antigen (PA), the cell-binding component of anthrax toxin. However, AVA requires a five-course regimen to induce immunity, along with an annual booster, and is composed of undefined culture supernatants from a PA-secreting strain. In addition, it appears to be ineffective against strains that lack anthrax toxin. Here, we investigated a vaccine formulation consisting of recombinant proteins from a surface-localized heme transport system containing near-iron transporter (NEAT) domains and its efficacy as a vaccine for anthrax disease. The cocktail of five NEAT domains was protective against a lethal challenge of inhaled bacillus spores at 3 and 28 weeks after vaccination. The reduction of the formulation to three NEATs (IsdX1, IsdX2, and Bslk) was as effective as a five-NEAT domain cocktail. The adjuvant alum, approved for use in humans, was as protective as Freund’s Adjuvant, and protective vaccination correlated with increased anti-NEAT antibody reactivity and reduced bacterial levels in organs. Finally, the passive transfer of anti-NEAT antisera reduced mortality and disease severity, suggesting the protective component is comprised of antibodies. Collectively, these results provide evidence that a vaccine based upon recombinant NEAT proteins should be considered in the development of a next-generation anthrax vaccine.

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Bacillus anthracis Protective Antigen Kinetics in Inhalation Spore-Challenged Untreated or Levofloxacin/ Raxibacumab-Treated New Zealand White Rabbits

Toxins ◽

10.3390/toxins5010120 ◽

2013 ◽

Vol 5 (1) ◽

pp. 120-138 ◽

Cited By ~ 21

Author(s):

Alfred Corey ◽

Thi-Sau Migone ◽

Sally Bolmer ◽

Michele Fiscella ◽

Chris Ward ◽

...

Keyword(s):

New Zealand ◽

Bacillus Anthracis ◽

Protective Antigen ◽

New Zealand White Rabbits

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Killed but Metabolically Active Bacillus anthracis Vaccines Induce Broad and Protective Immunity against Anthrax

Infection and Immunity ◽

10.1128/iai.00530-08 ◽

2009 ◽

Vol 77 (4) ◽

pp. 1649-1663 ◽

Cited By ~ 24

Author(s):

Justin Skoble ◽

John W. Beaber ◽

Yi Gao ◽

Julie A. Lovchik ◽

Laurie E. Sower ◽

...

Keyword(s):

Bacillus Anthracis ◽

Neutralizing Antibodies ◽

Protective Immunity ◽

Protective Antigen ◽

Excision Repair ◽

Uv Light ◽

Lethal Factor ◽

Point Mutations ◽

Anthrax Vaccine ◽

Edema Factor

ABSTRACTBacillus anthracisis the causative agent of anthrax. We have developed a novel whole-bacterial-cell anthrax vaccine utilizingB. anthracisthat is killed but metabolically active (KBMA). Vaccine strains that are asporogenic and nucleotide excision repair deficient were engineered by deleting thespoIIEanduvrABgenes, renderingB. anthracisextremely sensitive to photochemical inactivation with S-59 psoralen and UV light. We also introduced point mutations into thelefandcyagenes, which allowed inactive but immunogenic toxins to be produced. Photochemically inactivated vaccine strains maintained a high degree of metabolic activity and secreted protective antigen (PA), lethal factor, and edema factor. KBMAB. anthracisvaccines were avirulent in mice and induced less injection site inflammation than recombinant PA adsorbed to aluminum hydroxide gel. KBMAB. anthracis-vaccinated animals produced antibodies against numerous anthrax antigens, including high levels of anti-PA and toxin-neutralizing antibodies. Vaccination with KBMAB. anthracisfully protected mice against challenge with lethal doses of toxinogenic unencapsulated Sterne 7702 spores and rabbits against challenge with lethal pneumonic doses of fully virulent Ames strain spores. Guinea pigs vaccinated with KBMAB. anthraciswere partially protected against lethal Ames spore challenge, which was comparable to vaccination with the licensed vaccine anthrax vaccine adsorbed. These data demonstrate that KBMA anthrax vaccines are well tolerated and elicit potent protective immune responses. The use of KBMA vaccines may be broadly applicable to bacterial pathogens, especially those for which the correlates of protective immunity are unknown.

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Neutralizing Antibodies and Persistence of Immunity following Anthrax Vaccination

Clinical and Vaccine Immunology ◽

10.1128/cvi.13.2.208-213.2006 ◽

2006 ◽

Vol 13 (2) ◽

pp. 208-213 ◽

Cited By ~ 17

Author(s):

James F. Hanson ◽

Sarah C. Taft ◽

Alison A. Weiss

Keyword(s):

Neutralizing Antibodies ◽

Protective Antigen ◽

Colorimetric Assay ◽

Lethal Factor ◽

Neutralization Activity ◽

Anthrax Vaccine ◽

Edema Factor ◽

Low Levels ◽

Antibody Levels ◽

Toxic Components

ABSTRACT Anthrax toxin consists of protective antigen (PA) and two toxic components, lethal factor (LF) and edema factor (EF). PA binds to mammalian cellular receptors and delivers the toxic components to the cytoplasm. PA is the primary antigenic component of the current anthrax vaccine. Immunity is due to the generation of antibodies that prevent the PA-mediated internalization of LF and EF. In this study, we characterized sera obtained from vaccinated military personnel. Anthrax vaccine is administered in a series of six injections at 0, 2, and 4 weeks and 6, 12, and 18 months, followed by annual boosters. The vaccination histories of the subjects were highly varied; many subjects had not completed the entire series, and several had not received annual boosters. We developed a simple colorimetric assay using alamarBlue dye to assess the antibody-mediated neutralization of LF-mediated toxicity to the J774A.1 murine macrophage cell line. Recently vaccinated individuals had high antibody levels and neutralizing activity. One individual who had not been boosted for 5 years had low immunoglobulin G antibody levels but a detectable neutralization activity, suggesting that this individual produced low levels of very active antibodies.

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Evaluation of the immune response induced by a nasal anthrax vaccine based on the protective antigen protein in anaesthetized and non-anaesthetized mice

Journal of Pharmacy and Pharmacology ◽

10.1211/jpp.58.4.0003 ◽

2006 ◽

Vol 58 (4) ◽

pp. 439-447 ◽

Cited By ~ 10

Author(s):

Brian R. Sloat ◽

Zhengrong Cui

Keyword(s):

Immune Response ◽

Protective Antigen ◽

Anthrax Vaccine ◽

Antigen Protein

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Recombinant Protective Antigen Anthrax Vaccine Improves Survival when Administered as a Postexposure Prophylaxis Countermeasure with Antibiotic in the New Zealand White Rabbit Model of Inhalation Anthrax

Clinical and Vaccine Immunology ◽

10.1128/cvi.00240-12 ◽

2012 ◽

Vol 19 (8) ◽

pp. 1158-1164 ◽

Cited By ~ 16

Author(s):

Elizabeth K. Leffel ◽

James S. Bourdage ◽

E. Diane Williamson ◽

Matthew Duchars ◽

Thomas R. Fuerst ◽

...

Keyword(s):

Immune Response ◽

New Zealand ◽

Survival Rate ◽

Protective Antigen ◽

Zealand White Rabbit ◽

Postexposure Prophylaxis ◽

Content Type ◽

New Zealand White Rabbit ◽

Inhalation Anthrax ◽

Recombinant Protective Antigen

ABSTRACTInhalation anthrax is a potentially lethal form of disease resulting from exposure to aerosolizedBacillus anthracisspores. Over the last decade, incidents spanning from the deliberate mailing ofB. anthracisspores to incidental exposures in users of illegal drugs have highlighted the importance of developing new medical countermeasures to protect people who have been exposed to “anthrax spores” and are at risk of developing disease. The New Zealand White rabbit (NZWR) is a well-characterized model that has a pathogenesis and clinical presentation similar to those seen in humans. This article reports how the NZWR model was adapted to evaluate postexposure prophylaxis using a recombinant protective antigen (rPA) vaccine in combination with an oral antibiotic, levofloxacin. NZWRs were exposed to multiples of the 50% lethal dose (LD50) ofB. anthracisspores and then vaccinated immediately (day 0) and again on day 7 postexposure. Levofloxacin was administered daily beginning at 6 to 12 h postexposure for 7 treatments. Rabbits were evaluated for clinical signs of disease, fever, bacteremia, immune response, and survival. A robust immune response (IgG anti-rPA and toxin-neutralizing antibodies) was observed in all vaccinated groups on days 10 to 12. Levofloxacin plus either 30 or 100 μg rPA vaccine resulted in a 100% survival rate (18 of 18 per group), and a vaccine dose as low as 10 μg rPA resulted in an 89% survival rate (16 of 18) when used in combination with levofloxacin. In NZWRs that received antibiotic alone, the survival rate was 56% (10 of 18). There was no adverse effect on the development of a specific IgG response to rPA in unchallenged NZWRs that received the combination treatment of vaccine plus antibiotic. This study demonstrated that an accelerated two-dose regimen of rPA vaccine coadministered on days 0 and 7 with 7 days of levofloxacin therapy results in a significantly greater survival rate than with antibiotic treatment alone. Combination of vaccine administration and antibiotic treatment may be an effective strategy for treating a population exposed to aerosolizedB. anthracisspores.

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