HEPA/vaccine plan for indoor anthrax remediation.
Ontology highlight
ABSTRACT:
SUBMITTER: Wein LM
PROVIDER: S-EPMC3294362 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:The manufacture of the UK Anthrax vaccine (AVP) focuses on the production of Protective Antigen (PA) from the Bacillus anthracis Sterne strain. Although used for decades, several of AVP's fundamental properties are poorly understood, including its exact composition, the extent to which proteins other than PA may contribute to protection, and whether the degree of protection varies between individuals.This study involved three innovative investigations. Firstly, the composition of AVP was analyzed using liquid chromatography tandem mass-spectrometry (LC-MS/MS), requiring the development of a novel desorption method for releasing B. anthracis proteins from the vaccine's aluminum-containing adjuvant. Secondly, computational MHC-binding predictions using NetMHCIIpan were made for the eight most abundant proteins of AVP, for the commonest HLA alleles in multiple ethnic groups, and for multiple B. anthracis strains. Thirdly, antibody levels and toxin neutralizing antibody (TNA) levels were measured in sera from AVP human vaccinees for both PA and Lethal Factor (LF).It was demonstrated that AVP is composed of at least 138 B. anthracis proteins, including PA (65%), LF (8%) and Edema Factor (EF) (3%), using LC-MS/MS. NetMHCIIpan predicted that peptides from all eight abundant proteins are likely to be presented to T cells, a pre-requisite for protection; however, the number of such peptides varied considerably between different HLA alleles.These analyses highlight two important properties of the AVP vaccine that have not been established previously. Firstly, the effectiveness of AVP within humans may not depend on PA alone; there is compelling evidence to suggest that LF has a protective role, with computational predictions suggesting that additional proteins may be important for individuals with specific HLA allele combinations. Secondly, in spite of differences in the sequences of key antigenic proteins from different B. anthracis strains, these are unlikely to affect the cross-strain protection afforded by AVP.
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2014-05-01 | E-MTAB-2430 | biostudies-arrayexpress
Project description:There is a current biodefense interest in protection against anthrax. Here, we developed a new generation of stable and effective anthrax vaccine. We studied the immune response elicited by recombinant protective antigen (rPA) delivered intranasally with a novel mucosal adjuvant, a mast cell activator compound 48/80 (C48/80). The vaccine formulation was prepared in a powder form by spray-freeze-drying (SFD) under optimized conditions to produce particles with a target size of D(50) = 25 ?m, suitable for delivery to the rabbit nasal cavity. Physicochemical properties of the powder vaccines were characterized to assess their delivery and storage potential. Structural stability of rPA was confirmed by circular dichroism and attenuated total reflectance-Fourier transform infrared spectroscopy, whereas functional stability of rPA and C48/80 was monitored by cell-based assays. Animal study was performed using a unit-dose powder device for direct nasal application. Results showed that C48/80 provided effective mucosal adjuvant activity in rabbits. Freshly prepared SFD powder vaccine formulations or powders stored for over 2 years at room temperature elicited significantly elevated serum PA-specific and lethal toxin neutralization antibody titers that were comparable to that induced by intramuscular immunization with rPA. Nasal delivery of this vaccine formulation may be a viable alternative to the currently licensed vaccine or an attractive vaccine platform for other mucosally transmitted diseases.
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Project description:Interindividual variations in vaccine-induced immune responses are in part due to host genetic polymorphisms in the human leukocyte antigen (HLA) and other gene families. This study examined associations between HLA genotypes, haplotypes, and homozygosity and protective antigen (PA)-specific cellular immune responses in healthy subjects following immunization with Anthrax Vaccine Adsorbed (AVA). While limited associations were observed between individual HLA alleles or haplotypes and variable lymphocyte proliferative (LP) responses to AVA, analyses of homozygosity supported the hypothesis of a "heterozygote advantage." Individuals who were homozygous for any HLA locus demonstrated significantly lower PA-specific LP than subjects who were heterozygous at all eight loci (median stimulation indices [SI], 1.84 versus 2.95, P = 0.009). Similarly, we found that class I (HLA-A) and class II (HLA-DQA1 and HLA-DQB1) homozygosity was significantly associated with an overall decrease in LP compared with heterozygosity at those three loci. Specifically, individuals who were homozygous at these loci had significantly lower PA-specific LP than subjects heterozygous for HLA-A (median SI, 1.48 versus 2.13, P = 0.005), HLA-DQA1 (median SI, 1.75 versus 2.11, P = 0.007), and HLA-DQB1 (median SI, 1.48 versus 2.13, P = 0.002) loci, respectively. Finally, homozygosity at an increasing number (? 4) of HLA loci was significantly correlated with a reduction in LP response (P < 0.001) in a dose-dependent manner. Additional studies are needed to reproduce these findings and determine whether HLA-heterozygous individuals generate stronger cellular immune response to other virulence factors (Bacillus anthracis LF and EF) than HLA-homozygous subjects.
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Project description:BACKGROUND:Strategies to implement post exposure prophylaxis (PEP) in case of an anthrax bioterror event are needed. To increase the number of doses of vaccine available we evaluated reducing the amount of vaccine administered at each of the vaccinations, and reducing the number of doses administered. METHODS:Healthy male and non-pregnant female subjects between the ages of 18 and 65 were enrolled and randomized 1:1:1:1 to one of four study arms to receive 0.5 mL (standard dose) of vaccine subcutaneously (SQ) at: (A) days 0, 14; (B) days 0 and 28; (C) days 0, 14, and 28; or (D) 0.25 mL at days 0, 14, and 28. A booster was provided on day 180. Safety was assessed after each dose. Blood was obtained on days 0, 7, 14, 21, 28, 35, 42, 49, 56, 63, 70, 84, 100, 180, and 201 and both Toxin Neutralizing antibody and anti-PA IgG antibody measured. RESULTS:Almost all subjects developed some local reactions with 46-64% reported to be of moderate severity and 3.3% severe during the primary series. Vaccine groups that included a day 14 dose induced a ? 4 fold antibody rise in more subjects on days 21, 28, and 35 than the arm without a day 14 dose. However, schedules with a full day 28 dose induced higher peak levels of antibody that persisted longer. The half dose regimen did not induce antibody as well as the full dose study arms. CONCLUSION:Depending on the extent of the outbreak, effectiveness of antibiotics and availability of vaccine, the full dose 0, 28 or 0, 14, 28 schedules may have advantages.
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Project description:Bacillus anthracis is a sporulating Gram-positive bacterium that is the causative agent of anthrax and a potential weapon of bioterrorism. The U.S.-licensed anthrax vaccine is made from an incompletely characterized culture supernatant of a nonencapsulated, toxigenic strain (anthrax vaccine absorbed [AVA]) whose primary protective component is thought to be protective antigen (PA). AVA is effective in protecting animals and elicits toxin-neutralizing antibodies in humans, but enthusiasm is dampened by its undefined composition, multishot regimen, recommended boosters, and potential for adverse reactions. Improving next-generation anthrax vaccines is important to safeguard citizens and the military. Here, we report that vaccination with recombinant forms of a conserved domain (near-iron transporter [NEAT]), common in Gram-positive pathogens, elicits protection in a murine model of B. anthracis infection. Protection was observed with both Freund's and alum adjuvants, given subcutaneously and intramuscularly, respectively, with a mixed composite of NEATs. Protection correlated with an antibody response against the NEAT domains and a decrease in the numbers of bacteria in major organs. Anti-NEAT antibodies promote opsonophagocytosis of bacilli by alveolar macrophages. To guide the development of inactive and safe NEAT antigens, we also report the crystal structure of one of the NEAT domains (Hal) and identify critical residues mediating its heme-binding and acquisition activity. These results indicate that we should consider NEAT proteins in the development of an improved antianthrax vaccine.
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Project description:The recent use of Bacillus anthracis as a bioweapon has stimulated the search for novel antitoxins and vaccines that act rapidly and with minimal adverse effects. B. anthracis produces an AB-type toxin composed of the receptor-binding moiety protective antigen (PA) and the enzymatic moieties edema factor and lethal factor. PA is a key target for both antitoxin and vaccine development. We used the icosahedral insect virus Flock House virus as a platform to display 180 copies of the high affinity, PA-binding von Willebrand A domain of the ANTXR2 cellular receptor. The chimeric virus-like particles (VLPs) correctly displayed the receptor von Willebrand A domain on their surface and inhibited lethal toxin action in in vitro and in vivo models of anthrax intoxication. Moreover, VLPs complexed with PA elicited a potent toxin-neutralizing antibody response that protected rats from anthrax lethal toxin challenge after a single immunization without adjuvant. This recombinant VLP platform represents a novel and highly effective, dually-acting reagent for treatment and protection against anthrax.
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