Efficacy of therapeutically administered gepotidacin in a rabbit model of inhalational anthrax.

Bacillus anthracis is a Gram-positive Centers for Disease Control and Prevention category "A" biothreat pathogen. Without early treatment, inhalation of anthrax spores with progression to inhalational anthrax disease is associated with high fatality rates. Gepotidacin is a novel first-in-class triazaacenaphthylene antibiotic that inhibits bacterial DNA replication by a distinct mechanism of action and is being evaluated for use against biothreat and conventional pathogens. Gepotidacin selectively inhibits bacterial DNA replication via a unique binding mode and has in vitro activity against a collection of B. anthracis isolates including antibacterial-resistant strains, with the MIC90 ranging from 0.5 to 1 µg/mL. In vivo activity of gepotidacin was also evaluated in the New Zealand White rabbit model of inhalational anthrax. The primary endpoint was survival, with survival duration and bacterial clearance as secondary endpoints. The trigger for treatment was the presence of anthrax protective antigen in serum. New Zealand White rabbits were dosed intravenously for 5 days with saline or gepotidacin at 114 mg/kg/d to simulate a dosing regimen of 1,000 mg intravenous (i.v.) three times a day (TID) in humans. Gepotidacin provided a survival benefit compared to saline control, with 91% survival (P-value: 0.0001). All control animals succumbed to anthrax and were found to be blood- and organ culture-positive for B. anthracis. The novel mode of action, in vitro microbiology, preclinical safety, and animal model efficacy data, which were generated in line with Food and Drug Administration Animal Rule, support gepotidacin as a potential treatment for anthrax in an emergency biothreat situation.

CDC Guidelines for the Prevention and Treatment of Anthrax, 2023.

This report updates previous CDC guidelines and recommendations on preferred prevention and treatment regimens regarding naturally occurring anthrax. Also provided are a wide range of alternative regimens to first-line antimicrobial drugs for use if patients have contraindications or intolerances or after a wide-area aerosol release of: Bacillus anthracis spores if resources become limited or a multidrug-resistant B. anthracis strain is used (Hendricks KA, Wright ME, Shadomy SV, et al.; Workgroup on Anthrax Clinical Guidelines. Centers for Disease Control and Prevention expert panel meetings on prevention and treatment of anthrax in adults. Emerg Infect Dis 2014;20:e130687; Meaney-Delman D, Rasmussen SA, Beigi RH, et al. Prophylaxis and treatment of anthrax in pregnant women. Obstet Gynecol 2013;122:885-900; Bradley JS, Peacock G, Krug SE, et al. Pediatric anthrax clinical management. Pediatrics 2014;133:e1411-36). Specifically, this report updates antimicrobial drug and antitoxin use for both postexposure prophylaxis (PEP) and treatment from these previous guidelines best practices and is based on systematic reviews of the literature regarding 1) in vitro antimicrobial drug activity against B. anthracis; 2) in vivo antimicrobial drug efficacy for PEP and treatment; 3) in vivo and human antitoxin efficacy for PEP, treatment, or both; and 4) human survival after antimicrobial drug PEP and treatment of localized anthrax, systemic anthrax, and anthrax meningitis. Changes from previous CDC guidelines and recommendations include an expanded list of alternative antimicrobial drugs to use when first-line antimicrobial drugs are contraindicated or not tolerated or after a bioterrorism event when first-line antimicrobial drugs are depleted or ineffective against a genetically engineered resistant: B. anthracis strain. In addition, these updated guidelines include new recommendations regarding special considerations for the diagnosis and treatment of anthrax meningitis, including comorbid, social, and clinical predictors of anthrax meningitis. The previously published CDC guidelines and recommendations described potentially beneficial critical care measures and clinical assessment tools and procedures for persons with anthrax, which have not changed and are not addressed in this update. In addition, no changes were made to the Advisory Committee on Immunization Practices recommendations for use of anthrax vaccine (Bower WA, Schiffer J, Atmar RL, et al. Use of anthrax vaccine in the United States: recommendations of the Advisory Committee on Immunization Practices, 2019. MMWR Recomm Rep 2019;68[No. RR-4]:1-14). The updated guidelines in this report can be used by health care providers to prevent and treat anthrax and guide emergency preparedness officials and planners as they develop and update plans for a wide-area aerosol release of B. anthracis.

LETHAL TOXIN NEUTRALIZING ANTIBODY RESPONSE INDUCED FOLLOWING ORAL VACCINATION WITH A MICROENCAPSULATED BACILLUS ANTHRACIS STERNE STRAIN 34F2 VACCINE PROOF-OF-CONCEPT STUDY IN WHITE-TAILED DEER (ODOCOILEUS VIRGINIANUS).

Improved methods are needed to prevent wildlife deaths from anthrax. Caused by Bacillus anthracis, naturally occurring outbreaks of anthrax are frequent but unpredictable. The commercially available veterinary vaccine is labeled for subcutaneous injection and is impractical for large-scale wildlife vaccination programs; therefore, oral vaccination is the most realistic method to control and prevent these outbreaks. We reported the induction of an anthrax-specific lethal toxin (LeTx) neutralizing antibody response in mice following oral vaccination with alginate microcapsules containing B. anthracis Sterne strain 34F2 spores, coated with poly-L-lysine (PLL) and vitelline protein B (VpB). We continued evaluating our novel vaccine formulation through this proof-of-concept study in white-tailed deer (WTD; Odocoileus virginianus; n = 9). We orally vaccinated WTD via needle-free syringe with three formulations of the encapsulated vaccine: 1) PLL-VpB-coated microcapsules with 107-8 spores/ml (n = 5), 2) PLL-VpB-coated microcapsules with 109-10 spores/ml (n = 2), and 3) PLL-coated microcapsules with 109-10 spores/ml (n = 2). Although the limited sample sizes require continued experimentation, we observed an anthrax-specific antibody response in WTD serum following oral vaccination with PLL-coated microcapsules containing 109 spores/ ml. Furthermore, this antibody response neutralized anthrax LeTx in vitro, suggesting that continued development of this vaccine may allow for realistic wildlife anthrax vaccination programs.

Single Low-Dose Nanovaccine for Long-Term Protection against Anthrax Toxins.

Anthrax infections caused by Bacillus anthracis are an ongoing bioterrorism and livestock threat worldwide. Current approaches for management, including extended passive antibody transfusion, antibiotics, and prophylactic vaccination, are often cumbersome and associated with low patient compliance. Here, we report on the development of an adjuvanted nanotoxoid vaccine based on macrophage membrane-coated nanoparticles bound with anthrax toxins. This design leverages the natural binding interaction of protective antigen, a key anthrax toxin, with macrophages. In a murine model, a single low-dose vaccination with the nanotoxoids generates long-lasting immunity that protects against subsequent challenge with anthrax toxins. Overall, this work provides a new approach to address the ongoing threat of anthrax outbreaks and bioterrorism by taking advantage of an emerging biomimetic nanotechnology.

Anthrax toxin component, Protective Antigen, protects insects from bacterial infections.

Anthrax is a major zoonotic disease of wildlife, and in places like West Africa, it can be caused by Bacillus anthracis in arid nonsylvatic savannahs, and by B. cereus biovar anthracis (Bcbva) in sylvatic rainforests. Bcbva-caused anthrax has been implicated in as much as 38% of mortality in rainforest ecosystems, where insects can enhance the transmission of anthrax-causing bacteria. While anthrax is well-characterized in mammals, its transmission by insects points to an unidentified anthrax-resistance mechanism in its vectors. In mammals, a secreted anthrax toxin component, 83 kDa Protective Antigen (PA83), binds to cell-surface receptors and is cleaved by furin into an evolutionary-conserved PA20 and a pore-forming PA63 subunits. We show that PA20 increases the resistance of Drosophila flies and Culex mosquitoes to bacterial challenges, without directly affecting the bacterial growth. We further show that the PA83 loop known to be cleaved by furin to release PA20 from PA63 is, in part, responsible for the PA20-mediated protection. We found that PA20 binds directly to the Toll activating peptidoglycan-recognition protein-SA (PGRP-SA) and that the Toll/NF-κB pathway is necessary for the PA20-mediated protection of infected flies. This effect of PA20 on innate immunity may also exist in mammals: we show that PA20 binds to human PGRP-SA ortholog. Moreover, the constitutive activity of Imd/NF-κB pathway in MAPKK Dsor1 mutant flies is sufficient to confer the protection from bacterial infections in a manner that is independent of PA20 treatment. Lastly, Clostridium septicum alpha toxin protects flies from anthrax-causing bacteria, showing that other pathogens may help insects resist anthrax. The mechanism of anthrax resistance in insects has direct implications on insect-mediated anthrax transmission for wildlife management, and with potential for applications, such as reducing the sensitivity of pollinating insects to bacterial pathogens.

A recombinant chimeric protein of protective antigen and lethal factor from Bacillus anthracis in polymeric nanocapsules showed a strong immune response in mice: a potential high efficacy vaccine against anthrax.

Anthrax is a serious infectious disease caused by Bacillus anthracis, rod-shaped gram-positive bacteria. The disease infects both humans and animals and causes severe illness.  Many vaccines have been developed for anthrax, but the vaccine with very high efficacy is yet to be developed. To overcome the problems of efficacy posed by the existing vaccines, a recombinant chimeric fusion protein containing domain 1 of lethal factor (LFD1) and domain 4 of Bacillus anthracis protective antigen (PA4) was used as antigen in copolymeric nanocapsules (NCs). Accordingly, the solvent evaporation double emulsion method was used to produce NCs containing recombinant chimeric fusion protein (LFD1-PA4). Zeta sizer and potential of nanoparticles, nanoparticle loading efficiency, release pattern of recombinant protein, and the possible effect of polylactic acid-polyethylene glycol (PLA-PEG) nanoparticle production method were investigated. Mice were used to test and evaluate the immune response. The mean titer of antibody produced against loaded LFD1-PA4 compared to free form showed a significant difference. The difference in antibody titer between the groups of once injected, twice injected, and free antigen was significant, and the highest antibody titer was found in the mice twice injected. In addition, a single-time loaded injection showed significantly higher antibodies than the free form injection indicating that loaded LFD1-PA4 into PLA-PEG nanoparticles elicits a stronger immune response. This study showed that LFD1-PA4 fusion protein from Bacillus anthracis served as an active antigen in mice. Also, the nanocarrier (PLA-PEG) containing the antigen can stimulate the immune system in the mice, owing to their controlled release property.

A multipathogen DNA vaccine elicits protective immune responses against two class A bioterrorism agents, anthrax and botulism.

The potential use of biological agents has become a major public health concern worldwide. According to the CDC classification, Bacillus anthracis and Clostridium botulinum, the bacterial pathogens that cause anthrax and botulism, respectively, are considered to be the most dangerous potential biological agents. Currently, there is no licensed vaccine that is well suited for mass immunization in the event of an anthrax or botulism epidemic. In the present study, we developed a dual-expression system-based multipathogen DNA vaccine that encodes the PA-D4 gene of B. anthracis and the HCt gene of C. botulinum. When the multipathogen DNA vaccine was administered to mice and guinea pigs, high level antibody responses were elicited against both PA-D4 and HCt. Analysis of the serum IgG subtype implied a combined Th1/Th2 response to both antigens, but one that was Th2 skewed. In addition, immunization with the multipathogen DNA vaccine induced effective neutralizing antibody activity against both PA-D4 and HCt. Finally, the protection efficiency of the multipathogen DNA vaccine was determined by sequential challenge with 10 LD50 of B. anthracis spores and 10 LD50 of botulinum toxin, or vice versa, and the multipathogen DNA vaccine provided higher than 50% protection against lethal challenge with both high-risk biothreat agents. Our studies suggest the strategy used for this anthrax-botulinum multipathogen DNA vaccine as a prospective approach for developing emergency vaccines that can be immediately distributed on a massive scale in response to a biothreat emergency or infectious disease outbreak. Key points • A novel multipathogen DNA vaccine was constructed against anthrax and botulism. • Robust immune responses were induced following vaccination. • Suggests a potential vaccine development strategy against biothreat agents.

A putative exosporium lipoprotein GBAA0190 of Bacillus anthracis as a potential anthrax vaccine candidate.

BACKGROUND: Bacillus ancthracis causes cutaneous, pulmonary, or gastrointestinal forms of anthrax. B. anthracis is a pathogenic bacterium that is potentially to be used in bioterrorism because it can be produced in the form of spores. Currently, protective antigen (PA)-based vaccines are being used for the prevention of anthrax, but it is necessary to develop more safe and effective vaccines due to their prolonged immunization schedules and adverse reactions. METHODS: We selected the lipoprotein GBAA0190, a potent inducer of host immune response, present in anthrax spores as a novel potential vaccine candidate. Then, we evaluated its immune-stimulating activity in the bone marrow-derived macrophages (BMDMs) using enzyme-linked immunosorbent assay (ELISA) and Western blot analysis. Protective efficacy of GBAA0190 was evaluated in the guinea pig (GP) model. RESULTS: The recombinant GBAA0190 (r0190) protein induced the expression of various inflammatory cytokines including tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), monocyte chemoattractant protein-1 (MCP-1), and macrophage inflammatory protein-1α (MIP-1α) in the BMDMs. These immune responses were mediated through toll-like receptor 1/2 via activation of mitogen-activated protein (MAP) kinase and Nuclear factor-κB (NF-κB) pathways. We demonstrated that not only immunization of r0190 alone, but also combined immunization with r0190 and recombinant PA showed significant protective efficacy against B. anthracis spore challenges in the GP model. CONCLUSIONS: Our results suggest that r0190 may be a potential target for anthrax vaccine.

A novel bicistronic DNA vaccine with enhanced protective immune response against Bacillus anthracis through DNA prime-protein boost vaccination approach.

Anthrax, by Bacillus anthracis, remains a dreadful fatal hazard worldwide. The currently used anthrax vaccines are plagued by numerous issues that limit their widespread use. As an immunization approach targeting both extracellular antigens and toxins of B. anthracis may achieve better sterile immunity, the present investigation designed a bicistronic secretory anti-anthrax DNA vaccine targeting immune response against toxin and cells. The efficacy of the vaccine was compared with monocistronic DNA vaccines and the currently used anthrax vaccine. For this, mice were immunized with the developed vaccine containing pag (encoding protective antigen to block toxin) and eag genes (encoding EA1 to target cells) of B. anthracis through DNA-prime/Protein-boost (D/P) and DNA prime/DNA-boost (D/D) approaches. There was a >2 and > 5 fold increase in specific antibody level by D/D and D/P approaches respectively, on 42nd days post-immunization (dpi). Serum cytokine profiling showed that both Th1 and Th2 immune responses were elicited, with more Th2 responses in D/P strategy. More importantly, challenge with 100 times LD50 of B. anthracis at 42nd dpi exhibited maximum cumulative survival (83.33 %) by bicistronic D/P approach. Remarkably, immunization with EA1 delayed mortality onset in infection. The study forms the first report on complement-dependent bactericidal activity of antiEA1 antibodies. In short, co-immunization of PA and EA1 through the developed bicistronic DNA vaccine would be an effective immunization approach in anthrax vaccination. Further, D/P strategy could enhance vaccine-induced immunity against B. anthracis. Altogether, the study generates certain critical insights having direct applications in next-generation vaccine development against anthrax.

Efficacy assessment of a triple anthrax chimeric antigen as a vaccine candidate in guinea pigs: challenge test with Bacillus anthracis 17 JB strain spores.

CONTEXT: Bacillus anthracis secretes a tripartite toxin comprising protective antigen (PA), edema factor (EF), and lethal factor (LF). The human anthrax vaccine is mainly composed of the anthrax protective antigen (PA). Considerable efforts are being directed towards improving the efficacy of vaccines because the use of commercial anthrax vaccines (human/veterinary) is associated with several limitations. OBJECTIVE: In this study, a triple chimeric antigen referred to as ELP (gene accession no: MT590758) comprising highly immunogenic domains of PA, LF, and EF was designed, constructed, and assessed for the immunization capacity against anthrax in a guinea pig model. MATERIALS AND METHODS: Immunization was carried out considering antigen titration and immunization protocol. The immunoprotective efficacy of the ELP was evaluated in guinea pigs and compared with the potency of veterinary anthrax vaccine using a challenge test with B. anthracis 17JB strain spores. RESULTS: The results demonstrated that the ELP antigen induced strong humoral responses. The T-cell response of the ELP was found to be similar to PA, and showed that the ELP could protect 100%, 100%, 100%, 80% and 60% of the animals from 50, 70, 90, 100 and 120 times the minimum lethal dose (MLD, equal 5 × 105 spore/ml), respectively, which killed control animals within 48 h. DISCUSSION AND CONCLUSIONS: It is concluded that the ELP antigen has the necessary requirement for proper immunization against anthrax and it can be used to develop an effective recombinant vaccine candidate against anthrax.

Evaluation of the AV7909 Anthrax Vaccine Toxicity in Sprague Dawley Rats Following Three Intramuscular Administrations.

AV7909 is a next-generation anthrax vaccine under development for post-exposure prophylaxis following suspected or confirmed Bacillus anthracis exposure, when administered in conjunction with the recommended antibacterial regimen. AV7909 consists of the FDA-approved BioThrax® vaccine (anthrax vaccine adsorbed) and an immunostimulatory Toll-like receptor 9 agonist oligodeoxynucleotide adjuvant, CPG 7909. The purpose of this study was to evaluate the potential systemic and local toxicity of AV7909 when administered via repeat intramuscular injection to the right thigh muscle (biceps femoris) to male and female Sprague Dawley rats. The vaccine was administered on Days 1, 15, and 29 and the animals were assessed for treatment-related effects followed by a 2-week recovery period to evaluate the persistence or reversibility of any toxic effects. The AV7909 vaccine produced no apparent systemic toxicity based on evaluation of clinical observations, body weights, body temperature, clinical pathology, and anatomic pathology. Necrosis and inflammation were observed at the injection sites as well as in regional lymph nodes and adjacent tissues and were consistent with immune stimulation. Antibodies against B. anthracis protective antigen (PA) were detected in rats treated with the AV7909 vaccine, confirming relevance of this animal model for the assessment of systemic toxicity of AV7909. In contrast, sera of rats that received saline or soluble CPG 7909 alone were negative for anti-PA antibodies. Overall, 3 intramuscular immunizations of Sprague Dawley rats with AV7909 were well tolerated, did not induce mortality or any systemic adverse effects, and did not result in any delayed toxicity.

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

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.

Use of Anthrax Vaccine in the United States: Recommendations of the Advisory Committee on Immunization Practices, 2019.

This report updates the 2009 recommendations from the CDC Advisory Committee on Immunization Practices (ACIP) regarding use of anthrax vaccine in the United States (Wright JG, Quinn CP, Shadomy S, Messonnier N. Use of anthrax vaccine in the United States: recommendations of the Advisory Committee on Immunization Practices [ACIP)], 2009. MMWR Recomm Rep 2010;59[No. RR-6]). The report 1) summarizes data on estimated efficacy in humans using a correlates of protection model and safety data published since the last ACIP review, 2) provides updated guidance for use of anthrax vaccine adsorbed (AVA) for preexposure prophylaxis (PrEP) and in conjunction with antimicrobials for postexposure prophylaxis (PEP), 3) provides updated guidance regarding PrEP vaccination of emergency and other responders, 4) summarizes the available data on an investigational anthrax vaccine (AV7909), and 5) discusses the use of anthrax antitoxins for PEP. Changes from previous guidance in this report include the following: 1) a booster dose of AVA for PrEP can be given every 3 years instead of annually to persons not at high risk for exposure to Bacillus anthracis who have previously received the initial AVA 3-dose priming and 2-dose booster series and want to maintain protection; 2) during a large-scale emergency response, AVA for PEP can be administered using an intramuscular route if the subcutaneous route of administration poses significant materiel, personnel, or clinical challenges that might delay or preclude vaccination; 3) recommendations on dose-sparing AVA PEP regimens if the anthrax vaccine supply is insufficient to vaccinate all potentially exposed persons; and 4) clarification on the duration of antimicrobial therapy when used in conjunction with vaccine for PEP.These updated recommendations can be used by health care providers and guide emergency preparedness officials and planners who are developing plans to provide anthrax vaccine, including preparations for a wide-area aerosol release of B. anthracis spores. The recommendations also provide guidance on dose-sparing options, if needed, to extend the supply of vaccine to increase the number of persons receiving PEP in a mass casualty event.

BA3338, a surface layer homology domain possessing protein augments immune response and protection efficacy of protective antigen against Bacillus anthracis in mouse model.

AIM: Category A classified Bacillus anthracis is highly fatal pathogen that causes anthrax and creates challenges for global security and public health. In this study, development of a safe and ideal next-generation subunit anthrax vaccine has been evaluated in mouse model. METHOD AND RESULTS: Protective antigen (PA) and BA3338, a surface layer homology (SLH) domain possessing protein were cloned, expressed in heterologous system and purified by IMAC. Recombinant PA and BA3338 with alum were administered in mouse alone or in combination. The humoral and cell-mediated immune response was measured by ELISA and vaccinated animals were challenged with B. anthracis spores via intraperitoneal route. The circulating IgG antibody titre of anti-PA and anti-BA3338 was found significantly high in the first and second booster sera. A significant enhanced level of IL-4, IFN-γ and IL-12 was observed in antigens stimulated supernatant of splenocytes of PA + BA3338 vaccinated animals. A combination of PA and BA3338 provided 80% protection against 20 LD50 lethal dose of B. anthracis spores. CONCLUSION: Both antigens induced admirable humoral and cellular immune response as well as protective efficacy against B. anthracis spores. SIGNIFICANCE AND IMPACT OF THE STUDY: This study has been evaluated for the first time using BA3338 as a vaccine candidate alone or in combination with well-known anthrax vaccine candidate PA. The findings of this study demonstrated that BA3338 could be a co-vaccine candidate for development of dual subunit vaccine against anthrax.

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

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.

Is there an association between Stevens-Johnson Syndrome and vaccination? A systematic review.

AIMS AND BACKGROUND: It is essential to make sure that vaccines are safe, effective, and of good quality. In the past years, there have been some reports of adverse effects regarding vaccination. One of these adverse effects is the development of Stevens-Johnson syndrome. Stevens-Johnson syndrome is a rare, severe, skin disorder, that usually occurs after medication. In Europe, its estimated incidence is of 2-3 cases/million population/year. Therefore, the aim of this study was to investigate, through a systematic review, the association between vaccination and the development of Stevens-Johnson syndrome. MATERIALS AND METHODS: We performed a systematic review using PubMed, Scopus and Web of Science databases. We included studies dated between January 2000 and February 2018. The main selection criterion was the reporting of the disease, following vaccination. RESULTS: Ten studies were selected, from a total of 391 studies. Of these, 5 were case reports, 3 were cohort studies and 2 were case-control. All the studies were regarding cases of Stevens-Johnson syndrome after vaccination. The selected studies reported cases following vaccines such as influenza vaccine, smallpox, anthrax and tetanus vaccine, MMR vaccine, varicella vaccine, DTaP-IPV vaccine or rabies vaccine. None of the cohort studies reported statistically significant associations between vaccination and the syndrome. In the case-control studies, it was not observed significant increased risk for the Stevens-Johnson syndrome following the administration of vaccines. Regarding the case reports, there was not sufficient evidence to form a positive association between these two factors, and more studies are needed. CONCLUSIONS: In this review it was not possible to establish a positive relation between vaccination and the development of Stevens-Johnson syndrome.

Development of a novel multiepitope chimeric vaccine against anthrax.

Bacillus anthracis (BA), the etiological agent of anthrax, secretes protective antigen (PA), lethal factor (LF), and edema factor (EF) as major virulence mediators. Amongst these, PA-based vaccines are most effective for providing immunity against BA, but their low shelf life limits their usage. Previous studies showed that B-cell epitopes, ID II and ID III present in PA domain IV possess higher toxin neutralization activity and elicit higher antibody titer than ID I. Moreover, N-terminal region of both LF and EF harbors PA-binding sites which share 100% identity with each other. Here, in this study, we have developed an epitope-based chimeric vaccine (ID-LFn) comprising ID II-ID III region of PA and N-terminal region of LF. We have also evaluated its protective efficacy as well as stability and found it to be more stable than PA-based vaccine. Binding reactivities of ID-LFn with anti-PA/LF/EF antibodies were determined by ELISA. The stability of chimeric vaccine was assessed using circular dichroism spectroscopy. ID-LFn response was characterized by toxin neutralization, lymphocyte proliferation isotyping and cytokine profiling. The protective efficacy was analyzed by challenging ID-LFn-immunized mice with B. anthracis (pXO1+ and pXO2+). ID-LFn was found to be significantly stable as compared to PA. Anti-ID-LFn antibodies recognized PA, LF as well as EF. The T-cell response and the protective efficacy of ID-LFn were found to be almost similar to PA. ID-LFn exhibits equal protective efficacy in mice and possesses more stability as compared to PA along with the capability of recognizing PA, LF and EF at the same time. Thus, it can be considered as an improved vaccine against anthrax with better shelf life. ID-LFn, a novel multiepitope chimeric anthrax vaccine: ID-LFn comprises of immunodominant epitopes of domain 4 of PA and N-terminal homologous stretch of LF and EF. The administration of this protein as a vaccine provides protection against anthrax.

An Optimal Control Model to Reduce and Eradicate Anthrax Disease in Herbivorous Animals.

Anthrax is a fatal infectious disease which can affect animals and humans alike. Anthrax outbreaks occur periodically in animals, and they are of particular concern in herbivores, due to substantial economic consequences associated with animal death. The purpose of this study is to develop optimal control interventions that focus on vaccinating susceptible animals and/or removing infected carcasses. Our mathematical goal is to minimize the infectious animal population while reducing the cost of interventions. Optimal control interventions are derived theoretically, and numerical results with conclusions are presented.

Development of a novel chimeric PA-LF antigen of Bacillus anthracis, its immunological characterization and evaluation as a future vaccine candidate in mouse model.

Tremendous efforts are being made to develop an anthrax vaccine with long term protection. The main component of traditional anthrax vaccine is protective antigen (PA) with the trace amount of other proteins and bacterial components. In this study, we developed a recombinant PA-LF chimera antigen of Bacillus anthracis by fusing the PA domain 2-4 with lethal factor (LF) domain 1 and evaluated its protective potential against B. anthracis in mouse model. The anti-PA-LF chimera serum reacted with both PA and LF antigen, individually. The chimera elicited a strong antibody titer in mice with predominance of IgG1 isotype followed by IgG2b, IgG2a and IgG3. Cytokines were assessed in splenocytes of immunized mice and a significant up-regulation in the expression of IL-4, IL-10, IFN-γ and TNF-α was observed. The PA-LF chimera immunized mice exhibited 80% survival after challenge with virulent spores of B. anthracis. Pathological studies showed normal architecture in vital organs (spleen, lung, liver and kidney) of recovered immunized mice on 20 DPI after spore challenge. These findings suggested that PA-LF chimera of B. anthracis elicited good humoral as well as cell mediated immune response in mice, and thus, can be a potent vaccine candidate against anthrax.

A new triple chimeric protein as a high immunogenic antigen against anthrax toxins: theoretical and experimental analyses.

Background: Anthrax is a zoonotic disease caused by Bacillus anthracis and it can be deadly in 6 days. Considerable efforts have been conducted toward developing more effective veterinary and human anthrax vaccines because these common vaccines have several limitations. B. anthracis secretes a tripartite toxin, comprising protective antigen (PA), edema factor (EF), and lethal factor (LF). Several studies have shown important role of PA in protection of anthrax. LF and EF induce production of toxin neutralizing antibodies too. PA in fusion form with LF/EF has synergistic effects as a potential subunit vaccine. Methods: In this study, for the first time, a triple chimeric protein called ELP was modeled by fusing three different domains of anthrax toxic antigens, the N-terminal domains of EF and LF, and the C-terminal domain of PA as a high immunogenic antigen using Modeller 9.19 software. Immunogenicity of the ELP was assessed in guinea pigs using enzyme-linked immunosorbent assay (ELISA) test and MTT assay. Results: Theoretical studies and molecular dynamics (MD) simulation results suggest that the ELP model had acceptable quality and stability. Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) analysis of the purified ELP, its domains, and PA were matched with their molecular size and confirmed by western blotting analysis. In the immune guinea pigs, antibody was produced against all of the ELP domains. It was observed that ELP induced strong humoral response and could protect murine macrophage cell line (RAW 264.7 cells) against anthrax lethal toxin (LeTx). Conclusions: ELP chimeric antigen could be considered as a high immunogenic antigen.