Showing papers on "Anthrax vaccines published in 2016"

Acetalated Dextran Microparticulate Vaccine Formulated via Coaxial Electrospray Preserves Toxin Neutralization and Enhances Murine Survival Following Inhalational Bacillus Anthracis Exposure.

Abstract: Subunit formulations are regarded as the safest type of vaccine, but they often contain a protein-based antigen that can result in significant challenges, such as preserving antigenicity during formulation and administration. Many studies have demonstrated that encapsulation of protein antigens in polymeric microparticles (MPs) via emulsion techniques results in total IgG antibody titers comparable to alum formulations, however, the antibodies themselves are non-neutralizing. To address this issue, a coaxial electrohydrodynamic spraying (electrospray) technique is used to formulate a microparticulate-based subunit anthrax vaccine under conditions that minimize recombinant protective antigen (rPA) exposure to harsh solvents and high shear stress. rPA and the adjuvant resiquimod are encapsulated either in separate or the same acetalated dextran MPs. Using a murine model, the electrospray formulations lead to higher IgG2a subtype titers as well as comparable total IgG antibody titers and toxin neutralization relative to the FDA-approved vaccine (BioThrax). BioThrax provides no protection against a lethal inhalational challenge of the highly virulent Ames Bacillus anthracis anthrax strain, whereas 50% of the mice vaccinated with separately encapsulated electrospray MPs survive. Overall, this study demonstrates the potential use of electrospray for encapsulating protein antigens in polymeric MPs.

A CpG-Ficoll Nanoparticle Adjuvant for Anthrax Protective Antigen Enhances Immunogenicity and Provides Single-Immunization Protection against Inhaled Anthrax in Monkeys.

Abstract: Nanoparticulate delivery systems for vaccine adjuvants, designed to enhance targeting of secondary lymphoid organs and activation of APCs, have shown substantial promise for enhanced immunopotentiation. We investigated the adjuvant activity of synthetic oligonucleotides containing CpG-rich motifs linked to the sucrose polymer Ficoll, forming soluble 50-nm particles (DV230-Ficoll), each containing >100 molecules of the TLR9 ligand, DV230. DV230-Ficoll was evaluated as an adjuvant for a candidate vaccine for anthrax using recombinant protective Ag (rPA) from Bacillus anthracis. A single immunization with rPA plus DV230-Ficoll induced 10-fold higher titers of toxin-neutralizing Abs in cynomolgus monkeys at 2 wk compared with animals immunized with equivalent amounts of monomeric DV230. Monkeys immunized either once or twice with rPA plus DV230-Ficoll were completely protected from challenge with 200 LD50 aerosolized anthrax spores. In mice, DV230-Ficoll was more potent than DV230 for the induction of innate immune responses at the injection site and draining lymph nodes. DV230-Ficoll was preferentially colocalized with rPA in key APC populations and induced greater maturation marker expression (CD69 and CD86) on these cells and stronger germinal center B and T cell responses, relative to DV230. DV230-Ficoll was also preferentially retained at the injection site and draining lymph nodes and produced fewer systemic inflammatory responses. These findings support the development of DV230-Ficoll as an adjuvant platform, particularly for vaccines such as for anthrax, for which rapid induction of protective immunity and memory with a single injection is very important.

Next-Generation Bacillus anthracis Live Attenuated Spore Vaccine Based on the htrA - (High Temperature Requirement A) Sterne Strain

Abstract: Anthrax is a lethal disease caused by the gram-positive spore-producing bacterium Bacillus anthracis. Live attenuated vaccines, such as the nonencapsulated Sterne strain, do not meet the safety standards mandated for human use in the Western world and are approved for veterinary purposes only. Here we demonstrate that disrupting the htrA gene, encoding the chaperone/protease HtrA (High Temperature Requirement A), in the virulent Bacillus anthracis Vollum strain results in significant virulence attenuation in guinea pigs, rabbits and mice, underlying the universality of the attenuated phenotype associated with htrA knockout. Accordingly, htrA disruption was implemented for the development of a Sterne-derived safe live vaccine compatible with human use. The novel B. anthracis SterneΔhtrA strain secretes functional anthrax toxins but is 10–104-fold less virulent than the Sterne vaccine strain depending on animal model (mice, guinea pigs, or rabbits). In spite of this attenuation, double or even single immunization with SterneΔhtrA spores elicits immune responses which target toxaemia and bacteremia resulting in protection from subcutaneous or respiratory lethal challenge with a virulent strain in guinea pigs and rabbits. The efficacy of the immune-protective response in guinea pigs was maintained for at least 50 weeks after a single immunization.

Production of Functionally Active and Immunogenic Non-Glycosylated Protective Antigen from Bacillus anthracis in Nicotiana benthamiana by Co-Expression with Peptide-N-Glycosidase F (PNGase F) of Flavobacterium meningosepticum.

Abstract: Bacillus anthracis has long been considered a potential biological warfare agent, and therefore, there is a need for a safe, low-cost and highly efficient anthrax vaccine with demonstrated long-term stability for mass vaccination in case of an emergency. Many efforts have been made towards developing an anthrax vaccine based on recombinant protective antigen (rPA) of B. anthracis, a key component of the anthrax toxin, produced using different expression systems. Plants represent a promising recombinant protein production platform due to their relatively low cost, rapid scalability and favorable safety profile. Previous studies have shown that full-length rPA produced in Nicotiana benthamiana (pp-PA83) is immunogenic and can provide full protection against lethal spore challenge; however, further improvement in the potency and stability of the vaccine candidate is necessary. PA of B. anthracis is not a glycoprotein in its native host; however, this protein contains potential N-linked glycosylation sites, which can be aberrantly glycosylated during expression in eukaryotic systems including plants. This glycosylation could affect the availability of certain key epitopes either due to masking or misfolding of the protein. Therefore, a non-glycosylated form of pp-PA83 was engineered and produced in N. benthamiana using an in vivo deglycosylation approach based on co-expression of peptide-N-glycosidase F (PNGase F) from Flavobacterium meningosepticum. For comparison, versions of pp-PA83 containing point mutations in six potential N-glycosylation sites were also engineered and expressed in N. benthamiana. The in vivo deglycosylated pp-PA83 (pp-dPA83) was shown to have in vitro activity, in contrast to glycosylated pp-PA83, and to induce significantly higher levels of toxin-neutralizing antibody responses in mice compared with glycosylated pp-PA83, in vitro deglycosylated pp-PA83 or the mutated versions of pp-PA83. These results suggest that pp-dPA83 may offer advantages in terms of dose sparing and enhanced immunogenicity as a promising candidate for a safe, effective and low-cost subunit vaccine against anthrax.

Vaccines and me.

Abstract: I started my scientific career thinking I wanted to be an ecologist. I did some field work where I was an undergraduate at Miami University in Ohio but it became clear I wasn’t particularly suited for that type of research. I received a Ph.D. in Biology at the University of Notre Dame working on physiological adaptations to cold, isolating a thermal hysteresis protein (antifreeze protein) from Tenebrio molitor, the meal worm. I then went on to hone my skills as a biochemist at the University of Wisconsin, Department of Biochemistry, but soon got the opportunity to move to the Microbiology Department at the University of Geneva, Switzerland. It was 1981 and molecular biology had suddenly come of age with the ability to sequence DNA. It was an exciting time but also a very na€ıve time thinking that for instance the cloning of complicated enzymes, like the ones I had worked on at Wisconsin, was going to be simple and questions easily answered. I found myself in the laboratory of Daniel Kolokofsky. He was for all intent and purposes a molecular virologist. I knew little of microbiology much less of virology. After a period of time he asked me to consider working on a segmented RNA virus La Crosse Encephalitis Virus (LAC) (Bunyaviridae). His lab was mostly focused on mechanisms of transcription of VSV (Rhabdoviridae) and Sendai virus (Paramyxoviridae). His lab would complete the sequence of Sendai virus while I was there, a milestone at the time. I thought working on a different family of viruses and seeing how they compared to our understanding of their transcription and replication would be interesting. Coincidentally one summer, while I was a graduate student at Notre Dame, I had participated in a survey of mosquitoes in the South Bend, IN area because of an outbreak of LAC. At the time, it was simply to help subsidize my salary. My work with LAC showed that unlike rhabdo and paramyxo viruses, LAC, a bunya virus, utilized a remarkably similar transcription and replication pattern to the recently described cap-snatching mechanism of initiating transcription of influenza viruses. While flu viruses cap-snatched in the nucleus, bunyaviruses and subsequently arenaviruses all initiated transcription in the cytoplasm. It was an exciting time to be starting to work with viruses as the new molecular techniques allowed us to ascertain aspects of their molecular mechanisms much easier than previously. Although if one asks graduate students today what they think of the techniques we were using, I believe primitive might be a word that would be mentioned! In any case I was hooked as a virologist and remain hooked today. After leaving Dan’s lab I moved to Harvard Medical School and Boston’s Children’s Hospital. It was there that I really became a virologist interested in not just understanding their molecular mechanisms but pursuing ways to stop their infections. Boston’s Children’s Hospital, like all pediatric hospitals, has specific interests in diseases of infants such as Respiratory Syncytial virus (RSV). In the 1960s an RSV vaccine developed by NIH was used and had the unexpected consequence of causing more harm than any protection. The vaccine caused disease enhancement. This result was one of the first where vaccines which previously would be automatically considered safe, now had to be tested for the possibility that they might cause worsened disease. There was no good animal model to examine RSV pathogenesis and it remains that way today. The 1980s also saw the outbreak of HIV, including in infants. The first AIDS patient was seen at Boston’s Children’s Hospital sometime between 1983 and 1985. It left an indelible mark on those of us who were there and suddenly realized the extent of the outbreak and that it was nothing like we had ever seen or hopefully see ever again in our lifetime. The history of HIV vaccine development is well documented and has served as an example of how complicated a virus can be that infects the immune system. It became clear that in order to develop a vaccine we need first to understand the virus, the correlates of protection and how to manage such a complicated pathogen. Most of the work I did at Children’s focused on anti-viral treatments such as ribavirin. I also became intrigued by single cell parasitic infections and how little was known of these organisms and their cellular functions. I started to wonder how viruses could play a role in understanding host-cell machinery. Eventually my lab developed a hypothesis that testing the protozoan parasite Leishmania extracts for RNA-dependent RNA-polymerase activity would identify any single, double, segmented or non-segmented virus. We tested the hypothesis and identified a dsRNA virus now known as Leishmaniavirus. There are several strains of this virus and other single-cell organisms are now known to be infected with dsRNA viruses. In 1996, I accepted the job of Chair of Virology and Immunology at Texas Biomedical Research Institute (Texas Biomed) previously known as Southwest Foundation for Biomedical Research. My new job was to rebuild a department of virology and immunology. It was a challenging time to be building a new department. Funding at the National Institute for Allergy and Infectious Diseases (NIAID) was hovering at less than 10%

Licensure strategy for pre- and post-exposure prophylaxis of biothrax vaccine: the first vaccine licensed using the FDA animal rule.

Abstract: Introduction: The availability of a licensed anthrax vaccine that is safe, effective, and easy to administer for both pre- and post-exposure prophylaxis is critical to successfully manage and preve

A Comparison of the Adaptive Immune Response between Recovered Anthrax Patients and Individuals Receiving Three Different Anthrax Vaccines.

Abstract: Several different human vaccines are available to protect against anthrax. We compared the human adaptive immune responses generated by three different anthrax vaccines or by previous exposure to cutaneous anthrax. Adaptive immunity was measured by ELISPOT to count cells that produce interferon (IFN)-γ in response to restimulation ex vivo with the anthrax toxin components PA, LF and EF and by measuring circulating IgG specific to these antigens. Neutralising activity of antisera against anthrax toxin was also assayed. We found that the different exposures to anthrax antigens promoted varying immune responses. Cutaneous anthrax promoted strong IFN-γ responses to all three antigens and antibody responses to PA and LF. The American AVA and Russian LAAV vaccines induced antibody responses to PA only. The British AVP vaccine produced IFN-γ responses to EF and antibody responses to all three antigens. Anti-PA (in AVA and LAAV vaccinees) or anti-LF (in AVP vaccinees) antibody titres correlated with toxin neutralisation activities. Our study is the first to compare all three vaccines in humans and show the diversity of responses against anthrax antigens.

Development of a Sterne-Based Complement Fixation Test to Monitor the Humoral Response Induced by Anthrax Vaccines

Abstract: Anthrax is a zoonotic disease caused by Bacillus anthracis spore-forming bacterium. Since it is primarily a disease of animals, the control in animals, and humans depend on the prevention in livestock, principally cattle, sheep, and goats. Most veterinary vaccines utilize the toxigenic, uncapsulated (pXO1+/pXO2-) B. anthracis strain 34F2 which affords protection through the production of neutralizing antibodies directed to the toxin components Protective Antigen (PA), Lethal Factor (LF), and Edema Factor (EF). The titration of specific antibodies in sera of vaccinated animals is crucial to evaluate the efficacy of the vaccination and to obtain epidemiological information for an effective anthrax surveillance. In this study, we developed a Sterne-based Complement Fixation Test (CFT) to detect specific antibodies induced in animals vaccinated with Sterne 34F2. We assessed its efficacy in laboratory animals and under field conditions by monitoring the humoral response induced by vaccination in cattle. The results indicated that the Sterne-based CFT is able to correctly identify vaccinated animals. It proved to be a very sensitive and specific test. Moreover, the Sterne-based CFT offers many benefits with regard to costs, standardization and reproducibility of the assay procedure.

Quantitative Determination of Lethal Toxin Proteins in Culture Supernatant of Human Live Anthrax Vaccine Bacillus anthracis A16R

Abstract: Bacillus anthracis (B. anthracis) is the etiological agent of anthrax affecting both humans and animals. Anthrax toxin (AT) plays a major role in pathogenesis. It includes lethal toxin (LT) and edema toxin (ET), which are formed by the combination of protective antigen (PA) and lethal factor (LF) or edema factor (EF), respectively. The currently used human anthrax vaccine in China utilizes live-attenuated B. anthracis spores (A16R; pXO1+, pXO2−) that produce anthrax toxin but cannot produce the capsule. Anthrax toxins, especially LT, have key effects on both the immunogenicity and toxicity of human anthrax vaccines. Thus, determining quantities and biological activities of LT proteins expressed by the A16R strain is meaningful. Here, we explored LT expression patterns of the A16R strain in culture conditions using another vaccine strain Sterne as a control. We developed a sandwich ELISA and cytotoxicity-based method for quantitative detection of PA and LF. Expression and degradation of LT proteins were observed in culture supernatants over time. Additionally, LT proteins expressed by the A16R and Sterne strains were found to be monomeric and showed cytotoxic activity, which may be the main reason for side effects of live anthrax vaccines. Our work facilitates the characterization of anthrax vaccines components and establishment of a quality control standard for vaccine production which may ultimately help to ensure the efficacy and safety of the human anthrax vaccine A16R.

Revisiting the Concept of Targeting Only Bacillus anthracis Toxins as a Treatment for Anthrax.

Abstract: Protective antigen (PA)-based vaccines are effective in preventing the development of fatal anthrax disease both in humans and in relevant animal models. The Bacillus anthracis toxins lethal toxin (lethal factor [LF] plus PA) and edema toxin (edema factor [EF] plus PA) are essential for the establishment of the infection, as inactivation of these toxins results in attenuation of the pathogen. Since the toxins reach high toxemia levels at the bacteremic stages of the disease, the CDC's recommendations include combining antibiotic treatment with antitoxin (anti-PA) immunotherapy. We demonstrate here that while treatment with a highly potent neutralizing monoclonal antibody was highly efficient as postexposure prophylaxis treatment, it failed to protect rabbits with any detectable bacteremia (≥10 CFU/ml). In addition, we show that while PA vaccination was effective against a subcutaneous spore challenge, it failed to protect rabbits against systemic challenges (intravenous injection of vegetative bacteria) with the wild-type Vollum strain or a toxin-deficient mutant. To test the possibility that additional proteins, which are secreted by the bacteria under pathogenicity-stimulating conditions in vitro, may contribute to the vaccine's potency, we immunized rabbits with a secreted protein fraction from a toxin-null mutant. The antiserum raised against the secreted fraction reacts with the bacteria in an immunofluorescence assay. Immunization with the secreted protein fraction did not protect the rabbits against a systemic challenge with the fully pathogenic bacteria. Full protection was obtained only by a combined vaccination with PA and the secreted protein fraction. Therefore, these results indicate that an effective antiserum treatment in advanced stages of anthrax must include toxin-neutralizing antibodies in combination with antibodies against bacterial cell targets.

Identification of the pXO1 plasmid in attenuated Bacillus anthracis vaccine strains

Abstract: Anthrax toxins and capsule are the major virulence factors of Bacillus anthracis. They are encoded by genes located on the plasmids pXO1 and pXO2, respectively. The vaccine strain Pasteur II was produced from high temperature subcultures of B. anthracis, which resulted in virulence attenuation through the loss of the plasmid pXO1. However, it is unclear whether the high temperature culture completely abolishes the plasmid DNA or affects the replication of the plasmid pXO1. In this study, we tested 3 B. anthracis vaccine strains, including Pasteur II from France, Qiankefusiji II from Russia, and Rentian II from Japan, which were all generated from subcultures at high temperatures. Surprisingly, we detected the presence of pXO1 plasmid DNA using overlap PCR in all these vaccine strains. DNA sequencing analysis of overlap PCR products further confirmed the presence of pXO1. Moreover, the expression of the protective antigen (PA) encoded on pXO1 was determined by using SDS-PAGE and western blotting. In addition, we mimicked Pasteur's method and exposed the A16R vaccine strain, which lacks the pXO2 plasmid, to high temperature, and identified the pXO1 plasmid in the subcultures at high temperatures. This indicated that the high temperature treatment at 42.5°C was unable to eliminate pXO1 plasmid DNA from B. anthracis. Our results suggest that the attenuation of the Pasteur II vaccine strain is likely due to the impact of high temperature stress on plasmid replication, which in turn limits the copy number of pXO1. Our data provide new insights into the mechanisms of the remaining immunogenicity and toxicity of the vaccine strains.

Recent developments in the understanding and use of anthrax vaccine adsorbed: achieving more with less

Abstract: Anthrax Vaccine Adsorbed (AVA, BioThrax™) is the only Food and Drug Administration (FDA) approved vaccine for the prevention of anthrax in humans. Recent improvements in pre-exposure prophylaxis (PrEP) use of AVA include intramuscular (IM) administration and simplification of the priming series to three doses over 6 months. Administration IM markedly reduced the frequency, severity and duration of injection site reactions. Refinement of animal models for inhalation anthrax, identification of immune correlates of protection and cross-species modeling have created opportunities for reductions in the PrEP booster schedule and were pivotal in FDA approval of a post-exposure prophylaxis (PEP) indication. Clinical and nonclinical studies of accelerated PEP schedules and divided doses may provide prospects for shortening the PEP antimicrobial treatment period. These data may assist in determining feasibility of expanded coverage in a large-scale emergency when vaccine demand may exceed availability. Enhancements to the AVA formulation may broaden the vaccine's PEP application.

Progress toward the Development of a NEAT Protein Vaccine for Anthrax Disease.

Abstract: 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.

ELISA based anthrax antibody titer in cattle induced by locally prepared anthrax vaccine originated from Sterne F-24 strain in Bangladesh.

Abstract: Vaccination is usually practiced to prevent and control anthrax in Bangladesh. For this purpose, vaccine prepared from Sterne F-24 strain of Bacillus anthracis by Livestock Research Institute (LRI), Mohakhali, Dhakahas long been used in this country. However, in some cases anthrax occurred in vaccinated animals in Bangladesh. A total of 100 cattle at LalTeer Livestock Research and Development Farm, LalTeerLivestock Limited, Bangladesh, aging between 3-6 years and weighing between 250-400 kg were randomly selected for vaccination purpose. Blood samples (n=100) were collected before the vaccination for collecting pre-vaccination serum, andthe animals were vaccinated (at 1 mL/animal; 1x10 7 spores/mL) with the anthrax vaccine produced by LRI. All blood samples from the vaccinated animals were collected on day 7, 28, 60, 90, 120, 150, 180, 240, 270, 300, 330, and 360 of post-vaccination, and serum samples were prepared. The antibody levels in the serum samples against anthrax were monitored using an Enzyme-Linked Immunosorbent Assay (ELISA). Over the course of 12 months, the antibody titers were found at the level higher than the reference value. Though there were reports on anthrax suspected cases in this farm, no such cases were reported during the study period. Thus, the vaccine appears to induce adequate antibody response against anthrax in Bangladesh. Microbes and Health, January 2015. 4(1): 36-38

Animal anthrax in Sirajganj district of Bangladesh from 2010 to 2012

Abstract: A descriptive study was conducted using secondary surveillance data of animal anthrax from the Epidemiology Unit of Department of Livestock Services (DLS) for the years 2010, 2011 and 2012. The objectives of this study were to describe the pattern of animal anthrax in Sirajgong district of Bangladesh from 2010 to 2012 and to assess the current use of anthrax vaccine (Vaccine Coverage) based on animal, time and place. The study found that the disease was more prevalent in this district at the beginning of the early monsoon (Month of May, June when flood water enters) and the late monsoon (Month of September, October, when flood water recedes). Cattle were the predominant animal species affected with anthrax in this district followed by goats and sheep. The overall mean case fatality rate was 30.19%. The numbers of reported anthrax outbreaks in cattle had declined each year with 111 in 2010, 32 in 2011 and 20 in 2012. The annual mean vaccination coverage during the same years was 44.29%, 46.23% and 37.88% respectively. To reduce the number of outbreaks in animals and humans in Sirajganj district the annual vaccination coverage requires improvement. Behavior change through building greater awareness of anthrax is also needed at the farmer level for control and eradication of anthrax in animals as well as human. Asian J. Med. Biol. Res. December 2015, 1(3): 387-395

Prospects of the use of bacteriophage-based virus-like particles in the creation of anthrax vaccines

Abstract: The profitability of vaccine production is less than that of other pharmaceutical goods worldwide. Thus, the cost of the vaccine substance determines the range of vaccines available for use. This is of particular importance for veterinary vaccines. In this review, we have surveyed the published data on exploited vaccines and concluded that the immunogenicity of antigen substances based on whole virions is higher than that of soluble antigens. The physiological basis of this phenomenon remains unknown; however, it may explain why most of the described recombinant vaccines have not yet been put into practice. All practically implemented antiviral vaccines (except that for hepatitis B) are based on viral substances produced by conventional cultural technologies. In light of this observation, an approach to the development of a universal platform for recombinant vaccines produced in the form of virus-like particles is suggested. To this end, a technique of designing fused bifunctional derivatives of bacteriophage proteins containing antigens of interest should be involved. The approach is depicted with the use of the protective anthrax antigen, a conventional vaccine antigen.

Genome Sequence of the Soviet/Russian Bacillus anthracis Vaccine Strain 55-VNIIVViM

Abstract: Bacillus anthracis strain 55-VNIIVViM is a live-attenuated nonencapsulated Soviet/Russian veterinary anthrax vaccine strain. We report here the genome of 55-VNIIVViM and confirm its phylogenetic placement in the global population structure of B. anthracis.

A Study on molecular characterization of Razi Bacillus anthracis Sterne 34F2 substrain in Iran

Abstract: Anthrax, a zoonotic disease caused by Bacillus anthracis, has affected humans since ancient times. For genomic characterization of Razi B. anthracis Sterne 34F2 substrain, single nucleotide polymorphism (SNP) genotyping method developed by Van Erth, variable-number tandem-repeat (VNTR)-8 analysis proposed by Keim, and multiple-locus VNTR analysis (MLVA)-3 introduced by Levy were employed. In the SNPs typing system, where the nucleotide content of the genome at 13 evolutionary canonical loci was collectively analyzed, the originally South African 34F2 substrain was categorized in the A.Br.001/002 subgroup. In the VNTR-8 analysis, fragments with lengths of 314, 229, 162, 580, 532, 158, and 137 bp were identified at the following loci: vrrA, vrrB1, vrrB2, vrrC1, vrrC2, CG3, and pxO1, respectively. In addition, application of Levy's MLVA-3 genotyping method revealed that the genome of this strain carried 941, 451, and 864 bp fragments at AA03, AJ03, and AA07 loci, respectively. The present findings are undoubtedly helpful in meeting the requirements set by the World Organization for Animal Health (OIE) and World Health Organization (WHO) for anthrax vaccine manufacturers including Razi Institute. However, further similar studies are required to promote the current epidemiological knowledge of anthrax in Iran.

Perspectives of development of live recombinant anthrax vaccines based on opportunistic and apathogenic microorganisms

Abstract: Live genetic engineering anthrax vaccines on the platform of avirulent and probiotic micro-organisms are a safe and adequate alternative to preparations based on attenuated Bacillus anthracis strains. Mucosal application results in a direct contact of the vaccine preparations with mucous membranes in those organs arid tissues of the macro-organisms, that are exposed to the pathogen in the first place, resulting in a development of local and systemic immune response. Live recombinant anthrax vaccines could be used both separately as well as in a prime-boost immunization scheme. The review focuses on immunogenic and protective properties of experimental live genetic engineering prearations, created based on members of geni of Salmonella, Lactobacillus and adenoviruses.

Of an improved, human anthrax vaccine

Abstract: Human anthrax vaccines currently licensed in the United States and Western Europe consist of alum-precipitated or aluminum hydroxide-adsorbed supernatant material from fermentor cultures of toxigenic, nonencapsulated strains of Bacillus anthracis. These vaccines have several drawbacks, including the need for frequent boosters, the apparent inability to protect adequately against certain strains of B. anthracis, and occasional local reactogenicity. Studies are being undertaken to develop an improved human anthrax vaccine which is safe and efficacious, and which provides long-lasting immunity. Aspects being studied include the identification of antigens and epitopes responsible for eliciting protective immunity, the mechanisms 'f resistance to anthrax infection, the role of specific antibody in resistance, the differences in immunity elicited by living and chemical vaccines, the potential of new adjuvants to augment immunity, and the feasibility of developing safe vaccine strains having mutationally altered toxin genes. Both living and non-living (chemical) prototype vaccines are being developed and tested.

Immunobiological properties of new unencapsulated Bacillus anthracis 363/11 strain

Abstract: The results of a study on the immunobiological properties of a new, naturally attenuated, unencapsulated Bacillus anthracis 363/11 strain in comparison with the properties of the anthrax vaccine strain 55-VNIIVVIM, which is currently used in Russia and post-Soviet states, are presented in the article. Some differences in the phenotypes of the aforementioned strains are shown. The new strain caused lysis of sheep erythrocytes by α- but not by β-type; the strain had many more active proteinases and synthesized protocatechuic acid (PCA), in contrast to the vaccine strain. It was ascertained that immunization of animals by the new strain protects them from death after infection by field isolates of B. anthracis, while the 55-VNIIVVIM strain does not create this immunity. The data indicate that the new strain can be used to develop and improve anthrax prevention.

Bivalent anthrax vaccine

Abstract: The invention provides a genetic engineering bivalent (rPA+rLF) anthrax vaccine.Active ingredients of the bivalent anthrax vaccine include R178A/K197A mutant protein rPA of anthrax protective antigen and R491A/L514A mutant protein rLF of a lethal factor.The vaccine is prepared from the protective antigen PA and lethal factor LF dominant biological inactivation mutant protein, the advantages are that the protective antigen PA and lethal factor LF cannot be combined, capacity of generating anthrax toxin of a natural composition and action of lethal toxicity are lost, the immunogenicity and protectiveness of the dominant biological inactivation mutant protein rPA are superior to wild protective antigen PA, and the dominant biological inactivation mutant protein rLF can stimulate an organism to increase the immune protective effect; therefore, by means of the bivalent genetic engineering vaccine, the protection effect of the mutant protein rPA is greatly enhanced, five times or more of lethal dose of the lethal toxin can be resisted to, meanwhile the biologically inactivated rPA and rLF can further compete for combining with a receptor to inhibit activity of wild toxin, the purpose of neutralizing anthrax toxin is achieved, and it is inspected to achieve a good protection effect on inhaled infection anthrax.