Human Anthrax Research Articles

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.

Self-calibrating sensor with logic gate operation for anthrax biomarker based on nanoscaled bimetallic lanthanoid MOF

The bacillus anthracis is one of toxic bacterial spores that can cause human anthrax infections. In this effort, the nanoscaled bimetallic lanthanoid metal-organic framework (Ln-MOF), namely, [Tb0.43Eu1.57(1,4-phda)3(H2O)](H2O)2 was synthesized by tuning the mole ratio of Tb3+ and Eu3+ as a ratiometric luminescent sensor for anthrax biomarker (dipicolinic acid, DPA). The detection limits of this DPA sensor are as low as 5.9 nM in methanol and 0.17 μM in water which are lower than human infectious doses. This sensor can detect DPA via turn-on process with broad ranges at either low concentration (0−800 nM) in methanol or high concentration (20−100 μM) in an aqueous medium. Moreover, the bimetallic Ln-MOF’s emission colors in the presence of DPA are changed from red-orange to orange-yellow in methanol, and red-orange to green in water that can be easily seen in solution and film by naked-eyes. In addition, one-to-two logic gate operation for monitoring DPA concentration levels of this sensor has been developed. The luminescent probe is also applied for DPA detection in real tap-water and urine samples with good performances.

Human anthrax in Kyrgyz Republic: Epidemiology and clinical features

BackgroundBacillus anthracis infects both humans and animals which leads to anthrax disease. The disease is still a global issue as it occurs naturally and has a potential use for bioterrorism/bio-weapons agents. This study aimed to investigate the clinical and epidemiologic features of human anthrax that has been seen in Kyrgyzstan. MethodsThis study was carried out at the Osh Regional Hospital that is located in the southern regions of Kyrgyz Republic. Medical records of patient's diagnosed with cutaneous anthrax between 2005 and 2015 were reviewed. Epidemiology and clinical features of the infection and the effectiveness of antibiotic therapy were investigated. ResultsTwo hundred thirty four anthrax cases were reviewed. Among the patients, men in the 31–50 age group prevailed. Infection episodes that sought medical attention occurred mostly during the summer and autumn. Analysis of epidemiological data shows that anthrax contamination occurred as a result of direct contact with mainly farm animals, slaughtering, butchering and the selling of the meat. Cutaneous lesions were localized mostly in the upper extremities. Among the observed patients, a majority of the cases presented a mild form of the disease. The isolated strains of B. anthracis were mostly susceptible to amoxiclav, ofloxacin, 3rd generation of cephalosporins, doxycycline, ciprofloxacin, rifampicin, penicillin and streptomycin. A majority of the isolates were found to be resistant to ampicillin, gentamicin, chloramphenicol. ConclusionAnthrax is still an endemic disease that has lead to outbreaks in the Kyrgyz Republic. The transmission of human infection is seen by direct contact with ill animals or dead animal products. The common form seen in the clinical setting is cutaneous anthrax. Future studies should focus on the surveillance and infection control measurements associated with the anthrax.

Epidemiological Investigation and Etiological Analysis of a Cutaneous Anthrax Epidemic Caused by Butchering Sick Cattle in Guizhou, China.

A suspected human cutaneous anthrax epidemic caused by butchering sick cattle occurred in Zhijin County of Guizhou Province, Southwest of China, in 2016. Epidemiological investigation and etiological analysis were performed to provide a scientific basis for the source tracking of the epidemic. The epidemic was epidemiologically investigated, and skin blister samples collected from patients and soil samples collected from the butchering spots were used for Bacillus anthracis isolation. The suspicious B. anthracis isolates were identified using conventional methods and PCR, followed by genotyping using multiple-locus variable-number tandem repeats (VNTRs) analysis (MLVA-15) and canonical single-nucleotide polymorphism (canSNP). The genetic relationship of epidemic strains and isolates collected from other regions was analyzed. Epidemiological investigation results showed that the patients may be infected by B. anthracis during butchering sick cattle. Two suspected B. anthracis strains were isolated from blood samples and blister fluids, respectively. Conventional methods identified the two suspected isolates as B. anthracis, while PCR results showed that anti-protective antigen (PA) and capsule (CAP) gene were positive in the two isolates. MLVA-15 showed that the MLVA profiles of the two isolates were 9-20-12-53-16-2-8-8-8-4-4-4-4-10-4, which is different from the MLVA profiles of representative strains from other regions. CanSNP analysis showed that the two strains belonged to cluster A.Br.001/002. Clustering analysis and minimum spanning tree (MST) demonstrated that the two isolates were clustered with strains previously isolated from Guizhou Province. The results indicated that B. anthracis was the pathogen for this epidemic, and the patients were infected during butchering the sick. The genetic characteristics and the relationship of the B. anthracis isolates to strains from other regions indicated that the epidemic was a local occurrence.

Epidemiological and comparative genomic analysis of Bacillus anthracis isolated from northern Vietnam.

To understand the epidemiological and genetic background of anthrax cases occurring in Vietnam from 2011 to 2015, we surveilled and genetically analyzed Bacillus anthracis isolated in the north of the country. Epidemiological surveillance showed that most human cutaneous anthrax cases occurred in association with animal dissection. Whole-genome sequences were obtained from six B. anthracis strains from human patients with cutaneous anthrax in the endemic area. Comparative genomic analysis showed that the genetic homogeneity among Vietnamese B. anthracis strains was very high. All Vietnamese B. anthracis strains belonged to the canSNP lineage of A.Br.011/009, which mostly consists of strains of the trans-Eurasian (TEA) group, including the most closely related strain, Carbosap. To clarify the genetic diversity of Vietnamese strains and strains belonging to A.Br.011/009 and A.Br.008/011 canSNP lineages, we applied a reference genome-based single-nucleotide polymorphism (SNP) and gene-by-gene genomic analysis (whole-genome MLST) strategy. The phylogeny from core genome SNPs revealed that the Vietnamese strains were positioned close to each other; moreover, several SNPs specific to Vietnamese B. anthracis were identified. Whole-genome MLST analysis revealed the differences in the number of SNPs between Vietnamese strains, which could enable discrimination at the strain level.

Genetic diversity of Bacillus anthracis Ames lineage strains in China

BackgroundAnthrax is an endemic disease that persists in the rural regions of China. The global genetic population structure of B.anthracis has also been defined by the canonical single-nucleotide polymorphisms (canSNP) and multiple-locus variable-number tandem repeat analysis (MLVA). Five canSNP lineages were found in China, and the A.Br.Ames lineage has been the second predominant group in recent years in China. The objective of this study was to reveal genetic diversity of the Ames lineage strains by MLVA.MethodsTwo molecular typing methods, canSNP and MLVA with 15markers were used to study the genetic relationship among the Ames lineage strains. The outbreak information associated with these strains was also collected and investigated.ResultsFrom 2007 to 2018, a total of 21 human anthrax infection outbreaks (68 patients) associated with B. anthracis Ames lineage strains were reported in China. Ames lineage strain-associated human anthrax is mainly distributed in the northern part of China, including the provinces of Inner Mongolia, Liaoning, Gansu, and Xinjiang. In the study, a total of 30 Ames lineage strains were included and 10 MLVA15 genotypes were identified. These strains were mainly found in northeast China, Inner Mongolia and Liaoning. In recent years, the Ames lineage strains were isolated in the two provinces every year. The 18 Ames lineage strains isolated from Inner Mongolia were divided into eight MLVA15 genotypes. From 2010 to 2015, there were continuous reports of outbreaks in Keyouzhongqi County, Inner Mongolia, and the strains that were isolated annually in succession belonged to the MLVA15–30 genotype.ConclusionsThe Ames lineage strains are widely distributed in northern China. Their genetic diversity can be illustrated by the results of the MLVA. The genetic characteristics of the Ames lineage strains from outbreaks in different provinces varied. In some areas, human anthrax outbreaks occurred annually in succession, and these related strains grouped together. These observations indicate that the local environment was persistently contaminated with B. anthracis spores, vaccination of livestock should become the fundamental control measure in the areas.

Attitude and perception toward anthrax among cattle owners in selected rural communities in Bangladesh

Anthrax is a zoonotic disease caused by spore forming Bacillus anthracis. Throughout the world, it causes illness in livestock, wildlife and sometimes secondarily infects humans and causes a major public health threat. The study was conducted to assess cattle owners’ awareness, perceptions and attitudes toward anthrax. Data on awareness of anthrax, clinical signs of anthrax in animals and human, its routes of transmission and methods of prevention, the families’ consumption habits of anthrax-infected carcasses, and other family activities that increase exposure to anthrax were collected using an interviewer-administered questionnaire. Overall, the level of awareness amongst the farmers for anthrax was 71.5%. All of the farmers were aware that anthrax occurs in cattle, and 54% indicated the presence of unclotting blood oozing from natural orifices as a consistent finding in cattle that died of anthrax, whereas 71.2% of them indicated the presence of skin lesions as the most common sign of the disease in humans. The good efficacy of human anthrax treatment (62%), slaughter of moribund cattle and selling of meat from cattle found dead to unsuspecting consumers (68%), reluctance to lose animals (28%), and forgetting about anthrax (46.4%) were mentioned as the major reasons for consuming anthrax-infected carcasses. Of the respondents 79.2% of cattle owners indicated that they would not consume meat from cattle found dead, because they were discouraged by veterinary authorities, therefore introducing meat inspection services is likely to have a positive impact in preventing human anthrax outbreaks in selected areas of Bangladesh.
 Bangladesh J. of Livestock Res. 21-25: 168-172, 2018
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Rapid Nanopore Whole-Genome Sequencing for Anthrax Emergency Preparedness.

Human anthrax cases necessitate rapid response. We completed Bacillus anthracis nanopore whole-genome sequencing in our high-containment laboratory from a human anthrax isolate hours after receipt. The de novo assembled genome showed no evidence of known antimicrobial resistance genes or introduced plasmid(s). Same-day genomic characterization enhances public health emergency response.

Laboratory strains of Bacillus anthracis lose their ability to rapidly grow and sporulate compared to wildlife outbreak strains.

Bacillus anthracis is the causative agent of anthrax in animals and humans. The organism lies in a dormant state in the soil until introduced into an animal via, ingestion, cutaneous inoculation or inhalation. Once in the host, spores germinate into rapidly growing vegetative cells elaborating toxins. When animals die of anthrax, vegetative bacteria sporulate upon nutrient limitation in the carcass or soil while in the presence of air. After release into the soil environment, spores form a localized infectious zone (LIZ) at and around the carcass. Laboratory strains of B. anthracis produce fewer proteins associated with growth and sporulation compared to wild strains isolated from recent zoonotic disease events. We verified wild strains grow more rapidly than lab strains demonstrating a greater responsiveness to nutrient availability. Sporulation was significantly more rapid in these wild strains compared to lab strains, indicating wild strains are able to sporulate faster due to nutrient limitation while laboratory strains have a decrease in the speed at which they utilize nutrients and an increase in time to sporulation. These findings have implications for disease control at the LIZ as well as on the infectious cycle of this dangerous zoonotic pathogen.

Sporadic human cutaneous anthrax outbreak in Shaanxi Province, China: report of two cases from 2018

China’s compulsory annual livestock anthrax vaccination policy has remarkably reduced but not completely eradicated human anthrax infections. Herein we describe a sporadic human cutaneous anthrax outbreak involving two cases in 2018 in Shaanxi Province, both involving herdsman who dealt with unvaccinated and potentially sick cattle. Both patients showed Bacillus anthracis-positive blister smear and blood culture. Treatment with penicillin was followed by uneventful recovery for both. The prompt performance of the prophylactic measures successfully interrupted the further transmission of this sporadic human cutaneous anthrax outbreak.

Human Anthrax in Amhara Region, Ethiopia: A Retrospective Record Review 2013-2017

Yosef Gebreegziabher1*, Kinfe Haile2 and Zewdu Assefa3 1Ethiopian Field Epidemiology and Laboratory Training Program, Ethiopia 2Department of Public Health, St. Paul’s Hospital Millennium Medical College, Ethiopia 3Ethiopian Public Health Institute, Ethiopia *Corresponding Author: Yosef Gebreegziabher Ethiopian Field Epidemiology and Laboratory Training Program, Ethiopia E-mail: tabula.nassa@gmail.com Received Date: October 19, 2020; Accepted Date: November 09, 2020; Published Date: November 16, 2020 Citation: Gebreegziabher Y, Haile K, Assefa Z (2020) Human Anthrax in Amhara Region, Ethiopia:A Retrospective Record Review 2013-2017. Med Clin Rev. Vol. 6 No. 6: 109. DOI: 10.36648/2471-299X.6.6.109

Knowledge, attitudes, and practices related to anthrax and animal care: A case-control study in Georgia.

IntroductionAnthrax is endemic in Georgia and recent outbreaks prompted a livestock-handler case-control study with a component to evaluate anthrax knowledge, attitudes, and practices (KAP) among livestock handlers or owners.MethodsCases were handlers of livestock with confirmed animal anthrax from June 2013-May 2015. Handlers of four matched unaffected animals were selected as controls, two from the same village as the case animal (“village control”) and two from 3–10 km away (“area control”). Descriptive statistics were reported and conditional logistic regression was performed to estimate the magnitude of the association of cases with specific study KAP factors.ResultsCases were more likely male, had lower level college education, less animal care experience, and provided more animal care to their cattle. Cases had lower odds of burying a suddenly dead animal compared to all controls (Odds Ratio [OR]: 0.32, 95% Confidence interval [CI]:0.12, 0.88) and area controls (OR: 0.32, 95% CI: 0.11, 0.91). On an 8-point knowledge scale, cases having an animal with anthrax had a 1.31 times greater knowledge score compared to all controls (95% CI: 1.03, 1.67). Cases had higher odds of ever having human anthrax or knowing another person who had anthrax compared to all controls (OR: 4.56, 95% CI: 1.45, 14.30) and area controls (OR: 7.16, 95% CI: 1.52, 33.80).DiscussionCases were more knowledgeable of anthrax and had better anthrax prevention practices, but these are likely a result of the case investigation and ring vaccination following the death of their animal.ConclusionsThe findings reveal a low level of knowledge and practices related to anthrax control and prevention, and will guide educational material development to fill these gaps.

A One-Health lens for anthrax

A One-Health lens for anthrax

Detection of Bacillus anthracis in animal tissues using InBios active anthrax detect rapid test lateral flow immunoassay.

The Active Anthrax Detect (AAD) Rapid Test lateral flow immunoassay is a point-of-care assay that was under investigational use for detecting Bacillus anthracis capsular polypeptide (polyglutamic acid) in human blood, serum and plasma. Small sample volumes, rapid results and no refrigeration required allow for easy use in either the field or laboratory. Although the test was developed for use in suspect cases of human inhalation anthrax, its features also make it a potentially powerful tool for testing suspect animal cases. We tested animal tissue samples that were confirmed or ruled out for B. anthracis. The AAD Rapid Tests were also deployed in the field, testing animal carcasses during an anthrax outbreak in hippopotami (Hippopotamus amphibius) and Cape buffalo (Syncerus caffer) in Namibia. Evaluation of all samples showed a specificity of 82% and sensitivity of 98%. However, when the assay was used on specimens from only fresh carcasses (dead for <24h), the specificity increased to 96%. The AAD Rapid Test is a rapid and simple screening assay, but confirmatory testing needs to be done, especially when the age of the sample (days animal has been deceased) is unknown. SIGNIFICANCE AND IMPACT OF THE STUDY: In countries where anthrax is endemic, many human outbreaks are often caused by epizootics. Earlier detection of infected animals may allow for identification of exposed people, early implementation of prevention and control methods, and ultimately lessen the number of people and animals affected. Detection of Bacillus anthracis in animal tissues using a simple, rapid and field-deployable method would allow for faster outbreak response. We evaluated a simple sample collection and processing method for use with the Active Anthrax Detect Rapid Test lateral flow immunoassay to screen dead animals for anthrax.

The global distribution of Bacillus anthracis and associated anthrax risk to humans, livestock and wildlife.

Bacillus anthracis is a spore-forming, Gram-positive bacterium responsible for anthrax, an acute infection that most significantly affects grazing livestock and wild ungulates, but also poses a threat to human health. The geographic extent of B. anthracis is poorly understood, despite multi-decade research on anthrax epizootic and epidemic dynamics; many countries have limited or inadequate surveillance systems, even within known endemic regions. Here, we compile a global occurrence dataset of human, livestock and wildlife anthrax outbreaks. With these records, we use boosted regression trees to produce a map of the global distribution of B. anthracis as a proxy for anthrax risk. We estimate that 1.83 billion people (95% credible interval (CI): 0.59-4.16 billion) live within regions of anthrax risk, but most of that population faces little occupational exposure. More informatively, a global total of 63.8 million poor livestock keepers (95% CI: 17.5-168.6 million) and 1.1 billion livestock (95% CI: 0.4-2.3 billion) live within vulnerable regions. Human and livestock vulnerability are both concentrated in rural rainfed systems throughout arid and temperate land across Eurasia, Africa and North America. We conclude by mapping where anthrax risk could disrupt sensitive conservation efforts for wild ungulates that coincide with anthrax-prone landscapes.

The Ser/Thr protein kinase PrkC imprints phenotypic memory in Bacillus anthracis spores by phosphorylating the glycolytic enzyme enolase

Bacillus anthracis is the causative agent of anthrax in humans, bovine, and other animals. B. anthracis pathogenesis requires differentiation of dormant spores into vegetative cells. The spores inherit cellular components as phenotypic memory from the parent cell, and this memory plays a critical role in facilitating the spores' revival. Because metabolism initiates at the beginning of spore germination, here we metabolically reprogrammed B. anthracis cells to understand the role of glycolytic enzymes in this process. We show that increased expression of enolase (Eno) in the sporulating mother cell decreases germination efficiency. Eno is phosphorylated by the conserved Ser/Thr protein kinase PrkC which decreases the catalytic activity of Eno. We found that phosphorylation also regulates Eno expression and localization, thereby controlling the overall spore germination process. Using MS analysis, we identified the sites of phosphorylation in Eno, and substitution(s) of selected phosphorylation sites helped establish the functional correlation between phosphorylation and Eno activity. We propose that PrkC-mediated regulation of Eno may help sporulating B. anthracis cells in adapting to nutrient deprivation. In summary, to the best of our knowledge, our study provides the first evidence that in sporulating B. anthracis, PrkC imprints phenotypic memory that facilitates the germination process.

A cutaneous Anthrax outbreak in Koraput District of Odisha-India 2015

BackgroundCutaneous anthrax in humans is associated with exposure to infected animals or animal products and has a case fatality rate of up to 20% if untreated. During May to June 2015, an outbreak of cutaneous anthrax was reported in Koraput district of Odisha, India, an area endemic for anthrax. We investigated the outbreak to identify risk factors and recommend control measures.MethodWe defined a cutaneous anthrax case as skin lesions (e.g., papule, vesicle or eschar) in a person residing in Koraput district with illness onset between February 1 and July 15, 2015. We established active surveillance through a house to house survey to ascertain additional cases and conducted a 1:2 unmatched case control study to identify modifiable risk factors. In case control study, we included cases with illness onset between May 1 and July 15, 2015. We defined controls as neighbours of case without skin lesions since last 3 months. Ulcer exudates and rolled over swabs from wounds were processed in Gram stain in the Koraput district headquarter hospital laboratory.ResultWe identified 81 cases (89% male; median age 38 years [range 5–75 years]) including 3 deaths (case fatality rate = 4%). Among 37 cases and 74 controls, illness was significantly associated with eating meat of ill cattle (OR: 14.5, 95% CI: 1.4–85.7) and with close handling of carcasses of ill animals such as burying, skinning, or chopping (OR: 342, 95% CI: 40.5–1901.8). Among 20 wound specimens collected, seven showed spore-forming, gram positive bacilli, with bamboo stick appearance suggestive of Bacillus anthracis.ConclusionOur investigation revealed significant associations between eating and handling of ill animals and presence of anthrax-like organisms in lesions. We immediately initiated livestock vaccination in the area, educated the community on safe handling practices and recommended continued regular anthrax animal vaccinations to prevent future outbreaks.

ANTHRAX GLOBAL EPIZOOTOLOGY. 2. DISEASE INCIDENCE IN HUMANS AS INDICATOR OF EPIZOOTIC AND RISK FACTORS

The paper deals with the assessment of the implied associations between the epizootic and epidemic components of the veterinary anthrax epidemiology of animals and humans, as well as with the epidemic risk factors. Analysis of the statistical data for 2007–2017, available in ProMED international database, demonstrated that African, Asian and Near Eastern regions are permanently infected with human anthrax at the incidence rate of 1.0. The disease is very rarely reported in Europe, and it is exotic in the USA and South America. During the study period, the overall incidence amounted to over 3,700 humans: at an average of 340 humans annually ranging from min 81 to max 856. Total mortality amounted to 234 humans with average annual mortality of 21 humans ranging from min 6 to max 58, average annual lethality (patients’ mortality %) – 9.8 ranging from min 3.3 to max 39.5. For the assessment of the genuine interrelation of the incidence in humans and mortality in animals, we compared the statistic samples of the annual infection incidence in a number of the most epidemically and epizootically affected African, Asian and Near Eastern countries as the basic features of the epidemic and epizootic components of the veterinary anthrax epidemiology. The analysis demonstrated no statistical relation between the reported disease incidence in animals and humans. Substantial share of the disease incidence in humans is accounted for unidentifed sources of the infection. Consumption of infected products from domestic (up to 70%) and wild animals prevails among the trivial risk factors of zoonogenous infection in humans, while consumption of meat from domestic animals and contacts with diseased animals prevail among the lethality risk factors. The obtained results are indicative of multiple unidentifed aspects of veterinary anthrax epidemiology.

Plant-Made Antibodies: Properties and Therapeutic Applications.

A cost-effective plant platform for therapeutic monoclonal antibody production is both flexible and scalable. Plant cells have mechanisms for protein synthesis and posttranslational modification, including glycosylation, similar to those in animal cells. However, plants produce less complex and diverse Asn-attached glycans compared to animal cells and contain plant-specific residues. Nevertheless, plant-made antibodies (PMAbs) could be advantageous compared to those produced in animal cells due to the absence of a risk of contamination from nucleic acids or proteins of animal origin. In this review, the various platforms of PMAbs production are described, and the widely used transient expression system based on Agrobacterium-mediated delivery of genetic material into plant cells is discussed in detail. We examined the features of and approaches to humanizing the Asn-linked glycan of PMAbs. The prospects for PMAbs in the prevention and treatment of human infectious diseases have been illustrated by promising results with PMAbs against human immunodeficiency virus, rotavirus infection, human respiratory syncytial virus, rabies, anthrax and Ebola virus. The pre-clinical and clinical trials of PMAbs against different types of cancer, including lymphoma and breast cancer, are addressed. PMAb biosafety assessments in patients suggest that it has no side effects, although this does not completely remove concerns about the potential immunogenicity of some plant glycans in humans. Several PMAbs at various developmental stages have been proposed. Promise for the clinical use of PMAbs is aimed at the treatment of viral and bacterial infections as well as in anti-cancer treatment.

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.