{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,18]],"date-time":"2026-08-18T05:13:11Z","timestamp":1787029991345,"version":"build-2736575974"},"reference-count":38,"publisher":"MDPI AG","issue":"1","license":[{"start":{"date-parts":[[2026,1,9]],"date-time":"2026-01-09T00:00:00Z","timestamp":1767916800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Russian Ministry of Education and Science","award":["075-15-2025-525"],"award-info":[{"award-number":["075-15-2025-525"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Toxins"],"abstract":"<jats:p>Bacillus anthracis has three main virulence factors: an extracellular capsule and two binary toxins (lethal toxin\u2014consists of a lethal factor and a protective antigen, and edema toxin\u2014consists of an edema factor and a protective antigen). In the Russian Federation, the epidemiological situation regarding anthrax infection remains unfavorable. In the late stages of an anthrax infection, antibiotic therapy becomes ineffective and the patient dies within 24 h as a large amount of lethal toxin accumulates in the patient\u2019s blood. Antibodies capable of neutralising lethal toxin (LT) can be an effective treatment for these patients. The objective of the study was to construct a chimeric monoclonal antibody targeting the protective antigen of the LT and to elucidate its mechanism of toxin neutralization. In this work, a chimeric monoclonal antibody (xi1E10) directed against the protective antigen was successfully produced. Both in vitro and in vivo experiments demonstrated the capacity of xi1E10 to neutralize lethal toxin. Confocal microscopy revealed that xi1E10 effectively suppresses the formation of a functional pore, thereby blocking the translocation of the lethal factor into the cytosol. These findings indicate that the monoclonal antibody xi1E10 represents a promising candidate for the development of a therapeutic drug.<\/jats:p>","DOI":"10.3390\/toxins18010031","type":"journal-article","created":{"date-parts":[[2026,1,9]],"date-time":"2026-01-09T08:09:06Z","timestamp":1767946146000},"page":"31","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":1,"title":["Chimeric Antibody Engineering Against Bacillus anthracis Lethal Toxin: Neutralization Efficacy and Mechanism of Action"],"prefix":"10.3390","volume":"18","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-2838-6879","authenticated-orcid":false,"given":"Olga V.","family":"Kalmantaeva","sequence":"first","affiliation":[{"name":"State Research Center for Applied Microbiology and Biotechnology, 142279 Obolensk, Russia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Maksim A.","family":"Marin","sequence":"additional","affiliation":[{"name":"State Research Center for Applied Microbiology and Biotechnology, 142279 Obolensk, Russia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Anastasia A.","family":"Ershova","sequence":"additional","affiliation":[{"name":"State Research Center for Applied Microbiology and Biotechnology, 142279 Obolensk, Russia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-7478-909X","authenticated-orcid":false,"given":"Alena K.","family":"Ryabko","sequence":"additional","affiliation":[{"name":"State Research Center for Applied Microbiology and Biotechnology, 142279 Obolensk, Russia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yana O.","family":"Romanenko","sequence":"additional","affiliation":[{"name":"State Research Center for Applied Microbiology and Biotechnology, 142279 Obolensk, Russia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-1959-1739","authenticated-orcid":false,"given":"Tatyana I.","family":"Kombarova","sequence":"additional","affiliation":[{"name":"State Research Center for Applied Microbiology and Biotechnology, 142279 Obolensk, Russia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ivan A.","family":"Dyatlov","sequence":"additional","affiliation":[{"name":"State Research Center for Applied Microbiology and Biotechnology, 142279 Obolensk, Russia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Victoria V.","family":"Firstova","sequence":"additional","affiliation":[{"name":"State Research Center for Applied Microbiology and Biotechnology, 142279 Obolensk, Russia"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,1,9]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"47","DOI":"10.21055\/0370-1069-2025-2-47-55","article-title":"The Review of the Situation on Anthrax in 2024 in the World, the Forecast for 2025 in the Russian Federation","volume":"2","author":"Ryazanova","year":"2025","journal-title":"Probl. Osob. Opasnykh Infektsii [Probl. Part. Danger. Infect.]"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"42","DOI":"10.21055\/0370-1069-2016-4-42-46","article-title":"Outbreak of Anthrax in the Yamalo-Nenets Autonomous District in 2016, Epidemiological Peculiarities","volume":"4","author":"Popova","year":"2016","journal-title":"Probl. Osob. Opasnykh Infektsii [Probl. Part. Danger. Infect.]"},{"key":"ref_3","doi-asserted-by":"crossref","unstructured":"Avril, A., Guillier, S., and Rasetti-Escargueil, C. (2024). Development of Effective Medical Countermeasures Against the Main Biowarfare Agents: The Importance of Antibodies. Microorganisms, 12.","DOI":"10.3390\/microorganisms12122622"},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"56","DOI":"10.3201\/eid2301.160608","article-title":"Analysis of Anthrax Immune Globulin Intravenous with Antimicrobial Treatment in Injection Drug Users, Scotland, 2009\u20132010","volume":"23","author":"Cui","year":"2017","journal-title":"Emerg. Infect. Dis."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"1452","DOI":"10.3201\/eid2009.131481","article-title":"Confirmed Bacillus anthracis infection among persons who inject drugs, Scotland, 2009\u20132010","volume":"20","author":"Booth","year":"2014","journal-title":"Emerg. Infect. Dis."},{"key":"ref_6","doi-asserted-by":"crossref","unstructured":"Couse, Z., Cui, X., Li, Y., Moayeri, M., Leppla, S., and Eichacker, P.Q. (2021). A review of the efficacy of FDA-approved B. anthracis anti-toxin agents when combined with antibiotic or hemodynamic support in infection-or toxin-challenged preclinical models. Toxins, 13.","DOI":"10.3390\/toxins13010053"},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"833","DOI":"10.1038\/385833a0","article-title":"Crystal structure of the anthrax toxin protective antigen","volume":"385","author":"Petosa","year":"1997","journal-title":"Nature"},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"545","DOI":"10.1038\/nature14247","article-title":"Atomic structure of anthrax protective antigen pore elucidates toxin translocation","volume":"521","author":"Jiang","year":"2015","journal-title":"Nature"},{"key":"ref_9","doi-asserted-by":"crossref","unstructured":"Sun, J., and Jacquez, P. (2016). Roles of Anthrax Toxin Receptor 2 in Anthrax Toxin Membrane Insertion and Pore Formation. Toxins, 8.","DOI":"10.3390\/toxins8020034"},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"98","DOI":"10.32607\/actanaturae.11387","article-title":"Mechanism of blocking the activity of Bacillus anthracis lethal toxin by monoclonal antibodies","volume":"13","author":"Romanenko","year":"2021","journal-title":"Acta Naturae"},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"707","DOI":"10.1099\/13500872-142-3-707","article-title":"Characterization of lethal factor binding and cell receptor binding domains of protective antigen of Bacillus anthracis using monoclonal antibodies","volume":"142","author":"Little","year":"1996","journal-title":"Microbiology"},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"221","DOI":"10.1111\/j.1600-065X.2010.00969.x","article-title":"Progress and novel strategies in vaccine development and treatment of anthrax","volume":"239","author":"Chitlaru","year":"2011","journal-title":"Immunol. Rev."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"101","DOI":"10.2147\/IDR.S47305","article-title":"Raxibacumab: Potential role in the treatment of inhalational anthrax","volume":"7","author":"Kummerfeldt","year":"2014","journal-title":"Infect. Drug Resist."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"35","DOI":"10.2217\/17460913.4.1.35","article-title":"Anti-toxin antibodies in prophylaxis and treatment of inhalation anthrax","volume":"4","author":"Schneemann","year":"2009","journal-title":"Future Microbiol."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"823","DOI":"10.1007\/s40265-016-0577-0","article-title":"Obiltoxaximab: First global approval","volume":"76","author":"Greig","year":"2016","journal-title":"Drugs"},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"4878","DOI":"10.1128\/AAC.00546-16","article-title":"Revisiting the concept of targeting only Bacillus anthracis toxins as a treatment for anthrax","volume":"60","author":"Glinert","year":"2016","journal-title":"Antimicrob. Agents Chemother."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"365","DOI":"10.1089\/hs.2015.0032","article-title":"Antitoxin treatment of inhalation anthrax: A systematic review","volume":"1","author":"Huang","year":"2015","journal-title":"Health Secur."},{"key":"ref_18","doi-asserted-by":"crossref","unstructured":"Rubinson, L., Corey, A., and Hanfling, D. (2017). Estimation of time period for effective human inhalational anthrax treatment including antitoxin therapy. PLoS Curr., 9.","DOI":"10.1371\/currents.outbreaks.7896c43f69838f17ce1c2c372e79d55d"},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"232","DOI":"10.33029\/0206-4952-2021-42-3-232-242","article-title":"Toxin-neutralizing activity of monoclonal antibodies against the lethal toxin of Bacillus anthracis","volume":"42","author":"Romanenko","year":"2021","journal-title":"Immunology"},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"5425","DOI":"10.1128\/IAI.00261-07","article-title":"Human monoclonal antibodies against anthrax lethal factor and protective antigen act independently to protect against Bacillus anthracis infection and enhance endogenous immunity to anthrax","volume":"75","author":"Albrecht","year":"2007","journal-title":"Infect. Immun."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"1004","DOI":"10.3390\/toxins3081004","article-title":"Monoclonal antibody therapies against anthrax","volume":"3","author":"Chen","year":"2011","journal-title":"Toxins"},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"2505092","DOI":"10.1080\/19420862.2025.2505092","article-title":"Impact of antibody Fc engineering on translational pharmacology, and safety: Insights from industry case studies","volume":"17","author":"Brennan","year":"2025","journal-title":"MAbs"},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"2587580","DOI":"10.1080\/19420862.2025.2587580","article-title":"Pharmacokinetic and biodistribution analysis of monoclonal antibodies: A comprehensive study of antibody biodistribution and partitioning coefficients in mice","volume":"17","author":"Rabow","year":"2025","journal-title":"MAbs"},{"key":"ref_24","doi-asserted-by":"crossref","unstructured":"Gogesch, P., Dudek, S., van Zandbergen, G., Waibler, Z., and Anzaghe, M. (2021). The Role of Fc Receptors on the Effectiveness of Therapeutic Monoclonal Antibodies. Int. J. Mol. Sci., 22.","DOI":"10.3390\/ijms22168947"},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"72","DOI":"10.1208\/s12248-025-01060-7","article-title":"Effect of FcRn Binding on Monoclonal Antibody Disposition in the Brain","volume":"27","author":"Huang","year":"2025","journal-title":"AAPS J."},{"key":"ref_26","doi-asserted-by":"crossref","unstructured":"Jeon, J.H., Kim, Y.H., Choi, M.K., Kim, K.A., Lee, H.R., Jang, J., Kim, Y.R., Chun, J.H., Eo, S.K., and Kim, T.S. (2014). Bacillus anthracis genomic DNA enhances lethal toxin-induced cytotoxicity through TNF-\u03b1 production. BMC Microbiol., 14.","DOI":"10.1186\/s12866-014-0300-9"},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"1405","DOI":"10.1080\/14712598.2020.1801626","article-title":"Anthrax prevention through vaccine and post-exposure therapy","volume":"20","author":"Manish","year":"2020","journal-title":"Expert Opin. Biol. Ther."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"767","DOI":"10.1080\/19420862.2017.1323159","article-title":"Affinity of human IgG subclasses to mouse Fc\u03b3 receptors","volume":"9","author":"Dekkers","year":"2017","journal-title":"MAbs"},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"652","DOI":"10.1002\/cpdd.410","article-title":"Safety, Pharmacokinetics, and Immunogenicity of Obiltoxaximab After Intramuscular Administration to Healthy Humans","volume":"7","author":"Nagy","year":"2018","journal-title":"Clin. Pharmacol. Drug Dev."},{"key":"ref_30","doi-asserted-by":"crossref","unstructured":"Kontermann, R., and D\u00fcbel, S. (2001). Cloning Hybridoma cDNA by RACE. Antibody Engineering, Springer. Springer Lab Manuals.","DOI":"10.1007\/978-3-662-04605-0"},{"key":"ref_31","doi-asserted-by":"crossref","unstructured":"Haryadi, R., Ho, S., Kok, Y.J., Pu, H.X., Zheng, L., Pereira, N.A., and Song, Z. (2015). Optimization of heavy chain and light chain signal peptides for high level expression of therapeutic antibodies in CHO cells. PLoS ONE, 10.","DOI":"10.1371\/journal.pone.0116878"},{"key":"ref_32","unstructured":"(2021). Sanitary and Epidemiological Requirements for the Prevention of Infectious Diseases. Standard No. Sanitary rules and regulations \u2116 3.3686-21."},{"key":"ref_33","unstructured":"(2016). Environment, Housing and ManagementGuidelines for Accommodation and Care of Animals. (Standard No. State Standard \u2116 33215-2014)."},{"key":"ref_34","unstructured":"(2016). Guidelines for Accommodation and Care of Animals. Species-Specific Provisions for Laboratory Rodents and Rabbits. Standard No. State Standard \u2116 33216-2014."},{"key":"ref_35","unstructured":"(2010). Protection of Animals Used for Scientific Purposes. Standard No. Directive \u2116 2010\/63\/EU of the European Parliament and of the Council."},{"key":"ref_36","unstructured":"National Research Council (US) (2011). Committee for the Update of the Guide for the Care and Use of Laboratory Animals. Guide for the Care and Use of Laboratory Animals, National Academies Press (US). [8th, ed.]."},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"671","DOI":"10.1038\/nmeth.2089","article-title":"NIH Image to ImageJ: 25 years of image analysis","volume":"9","author":"Schneider","year":"2012","journal-title":"Nat. Methods"},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"213","DOI":"10.1111\/j.1365-2818.2006.01706.x","article-title":"A guided tour into subcellular colocalization analysis in light microscopy","volume":"224","author":"Bolte","year":"2006","journal-title":"J. Microsc."}],"container-title":["Toxins"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2072-6651\/18\/1\/31\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,1,9]],"date-time":"2026-01-09T08:15:26Z","timestamp":1767946526000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2072-6651\/18\/1\/31"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,1,9]]},"references-count":38,"journal-issue":{"issue":"1","published-online":{"date-parts":[[2026,1]]}},"alternative-id":["toxins18010031"],"URL":"https:\/\/doi.org\/10.3390\/toxins18010031","relation":{},"ISSN":["2072-6651"],"issn-type":[{"value":"2072-6651","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,1,9]]}}}