{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,15]],"date-time":"2026-10-15T05:33:26Z","timestamp":1792042406893,"version":"4.4.0"},"reference-count":50,"publisher":"Frontiers Media SA","license":[{"start":{"date-parts":[[2025,9,9]],"date-time":"2025-09-09T00:00:00Z","timestamp":1757376000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":["frontiersin.org"],"crossmark-restriction":true},"short-container-title":["Front. Microbiol."],"abstract":"<jats:sec><jats:title>Background<\/jats:title><jats:p><jats:italic>Pasteurella multocida<\/jats:italic> (<jats:italic>P. multocida<\/jats:italic>) is a globally significant pathogen causing severe infections in livestock, including hemorrhagic septicemia and respiratory diseases. Current vaccines offer limited serotype-specific protection, particularly against serotype A:3, a major cause of bovine respiratory disease. Extracellular products (ECPs) of bacteria, containing secreted proteins and enzymes, have shown promise as immunogens in other pathogens, but their potential against <jats:italic>P. multocida<\/jats:italic> remains unclear.<\/jats:p><\/jats:sec><jats:sec><jats:title>Methods<\/jats:title><jats:p>Extracellular products were isolated from <jats:italic>P. multocida<\/jats:italic> serotype A:3 strain PmQA-1 and characterized via SDS-PAGE, mass spectrometry, and enzymatic activity assays. Pathogenicity was evaluated by determining the median lethal dose (LD<jats:sub>50<\/jats:sub>) in mice. Mice were immunized with ECPs, formalin-killed cells (FKC), or a combination (FKC + ECPs), and immune responses (serum IgG, splenic lymphocyte proliferation, cytokine expression) were assessed over 28 days. Protective efficacy was tested via challenge with homologous (A:3) and heterologous (B:2, D:4) strains.<\/jats:p><\/jats:sec><jats:sec><jats:title>Results<\/jats:title><jats:p>Extracellular products contained 157 proteins (25\u2013100 kDa), including immunogenic factors like transferrin-binding protein A, and exhibited stable amylase activity. The LD<jats:sub>50<\/jats:sub> of ECPs in mice was 2.69 mg\/mouse, inducing lesions typical of <jats:italic>P. multocida<\/jats:italic> infection. ECP-immunized mice showed peak IgG levels at day 21, enhanced lymphocyte proliferation, and upregulated TNF-\u03b1, IFN-\u03b3, IL-1\u03b2, and IL-10 in key tissues. Challenge experiments demonstrated 100% survival against A:3 and B:2, and 90% against D:4, outperforming FKC and FKC + ECPs.<\/jats:p><\/jats:sec><jats:sec><jats:title>Conclusion<\/jats:title><jats:p>Extracellular products from <jats:italic>P. multocida<\/jats:italic> serotype A:3 induce robust humoral and cellular immunity, providing broad-spectrum protection against multiple serotypes. These findings support ECPs as a promising subunit vaccine candidate for controlling <jats:italic>P. multocida<\/jats:italic> infections in livestock.<\/jats:p><\/jats:sec>","DOI":"10.3389\/fmicb.2025.1674831","type":"journal-article","created":{"date-parts":[[2025,9,9]],"date-time":"2025-09-09T06:02:26Z","timestamp":1757397746000},"update-policy":"https:\/\/doi.org\/10.3389\/crossmark-policy","source":"Crossref","is-referenced-by-count":2,"title":["Immunoprotective effects of extracellular products of Pasteurella multocida on mice"],"prefix":"10.3389","volume":"16","author":[{"given":"Jingtao","family":"Li","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Wan","family":"Liu","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Xiaoyu","family":"Zhang","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yang","family":"Song","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Li","family":"Chen","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Qiumei","family":"Shi","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Tonglei","family":"Wu","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1965","published-online":{"date-parts":[[2025,9,9]]},"reference":[{"key":"B1","doi-asserted-by":"publisher","first-page":"64","DOI":"10.1016\/j.micpath.2017.12.044","article-title":"Aeromonas caviae alters the activities of ecto-enzymes that hydrolyze adenine nucleotides in fish thrombocytes.","volume":"115","author":"Baldissera","year":"2018","journal-title":"Microb. Pathog."},{"key":"B2","doi-asserted-by":"publisher","first-page":"9","DOI":"10.1016\/j.fsi.2013.10.003","article-title":"Effects of three strains of intestinal autochthonous bacteria and their extracellular products on the immune response and disease resistance of common carp, cyprinus carpio.","volume":"36","author":"Chi","year":"2014","journal-title":"Fish Shellfish Immunol."},{"key":"B3","doi-asserted-by":"publisher","first-page":"4345","DOI":"10.1016\/j.vaccine.2008.06.029","article-title":"Vaccination with pasteurella multocida recombinant OmpA induces strong but non-protective and deleterious th2-type immune response in mice.","volume":"26","author":"Dabo","year":"2008","journal-title":"Vaccine"},{"key":"B4","doi-asserted-by":"publisher","first-page":"207","DOI":"10.1186\/s12917-025-04668-1","article-title":"Pasteurella multocida filamentous hemagglutinin b1 (fhab1) gene is not involved with avian fowl cholera pathogenesis in turkey poults.","volume":"21","author":"Dassanayake","year":"2025","journal-title":"BMC Vet. Res."},{"key":"B5","doi-asserted-by":"publisher","first-page":"135","DOI":"10.1189\/jlb.4A0916-067RR","article-title":"Dihydrolipoamide dehydrogenase-lpd (rv0462)-specific t cell recall responses are higher in healthy household contacts of TB: A novel immunodominant antigen from m.","volume":"102","author":"Devasundaram","year":"2017","journal-title":"Tuberculosis. J. Leukoc. Biol."},{"key":"B6","doi-asserted-by":"publisher","first-page":"692","DOI":"10.3390\/ani14050692","article-title":"Genomic and proteomic analyses of extracellular products reveal major virulence factors likely accounting for differences in pathogenicity to bivalves between vibrio mediterranei strains.","volume":"14","author":"Fan","year":"2024","journal-title":"Animals"},{"key":"B7","doi-asserted-by":"publisher","first-page":"247","DOI":"10.3389\/fimmu.2019.00247","article-title":"Utility of hybrid transferrin binding protein antigens for protection against pathogenic neisseria species.","volume":"10","author":"Fegan","year":"2019","journal-title":"Front. Immunol."},{"key":"B8","doi-asserted-by":"publisher","first-page":"104380","DOI":"10.1016\/j.micpath.2020.104380","article-title":"Molecular pathogenesis of the hyaluronic acid capsule of pasteurella multocida.","volume":"149","author":"Guan","year":"2020","journal-title":"Microb. Pathog."},{"key":"B9","doi-asserted-by":"publisher","first-page":"e0059221","DOI":"10.1128\/jb.00592-21","article-title":"The role and targets of the RNA-binding protein ProQ in the gram-negative bacterial pathogen pasteurella multocida.","volume":"204","author":"Gulliver","year":"2022","journal-title":"J. Bacteriol."},{"key":"B10","doi-asserted-by":"publisher","first-page":"e39973","DOI":"10.1371\/journal.pone.0039973","article-title":"Screening of 71 p. Multocida proteins for protective efficacy in a fowl cholera infection model and characterization of the protective antigen PlpE.","volume":"7","author":"Hatfaludi","year":"2012","journal-title":"PLoS One"},{"key":"B11","doi-asserted-by":"publisher","first-page":"181","DOI":"10.3389\/fcimb.2016.00181","article-title":"Immunization with the MipA, skp, or ETEC_2479 antigens confers protection against enterotoxigenic e. Coli strains expressing different colonization factors in a mouse pulmonary challenge model.","volume":"6","author":"Hays","year":"2016","journal-title":"Front. Cell. Infect. Microbiol."},{"key":"B12","doi-asserted-by":"publisher","first-page":"912","DOI":"10.1128\/CVI.00621-12","article-title":"Cross-protective efficacy of recombinant transferrin-binding protein a of haemophilus parasuis in guinea pigs.","volume":"20","author":"Huang","year":"2013","journal-title":"Clin. Vaccine Immunol."},{"key":"B13","doi-asserted-by":"publisher","first-page":"64","DOI":"10.1515\/bmc-2018-0007","article-title":"Interferon-gamma (IFN-gamma): Exploring its implications in infectious diseases.","volume":"9","author":"Kak","year":"2018","journal-title":"Biomol. Concepts"},{"key":"B14","first-page":"209","article-title":"Effects of extracellular products of vibrio vulnificus on acanthopagrus schlegeli serum components in vitro and in vivo.","volume":"92","author":"Lee","year":"1997","journal-title":"Microbios"},{"key":"B15","doi-asserted-by":"publisher","first-page":"27","DOI":"10.1016\/j.vaccine.2005.07.079","article-title":"Immunogenicity and efficacy of three recombinant subunit pasteurella multocida toxin vaccines against progressive atrophic rhinitis in pigs.","volume":"24","author":"Liao","year":"2006","journal-title":"Vaccine"},{"key":"B16","doi-asserted-by":"publisher","first-page":"1104","DOI":"10.1094\/PHYTO-08-20-0372-R","article-title":"Extracellular amylase is required for full virulence and regulated by the global posttranscriptional regulator RsmA in xanthomonas campestris pathovar campestris.","volume":"111","author":"Lin","year":"2021","journal-title":"Phytopathology"},{"key":"B17","doi-asserted-by":"publisher","first-page":"119","DOI":"10.3354\/dao03337","article-title":"Atlantic salmon challenged with extracellular products from moritella viscosa.","volume":"133","author":"MacKinnon","year":"2019","journal-title":"Dis. Aquat. Org."},{"key":"B18","doi-asserted-by":"publisher","first-page":"970","DOI":"10.1111\/j.1365-2958.2006.05436.x","article-title":"An alpha-(1,4)-amylase is essential for alpha-(1,3)-glucan production and virulence in histoplasma capsulatum.","volume":"62","author":"Marion","year":"2006","journal-title":"Mol. Microbiol."},{"key":"B19","doi-asserted-by":"publisher","first-page":"1361","DOI":"10.1128\/IAI.00122-16","article-title":"The RNA-binding chaperone hfq is an important global regulator of gene expression in pasteurella multocida and plays a crucial role in production of a number of virulence factors, including hyaluronic acid capsule.","volume":"84","author":"Megroz","year":"2016","journal-title":"Infect. Immun."},{"key":"B20","first-page":"140","article-title":"Pasteurella multocida vaccine candidates: A systematic review.","volume":"12","author":"Mostaan","year":"2020","journal-title":"Avicenna J. Med. Biotechnol."},{"key":"B21","doi-asserted-by":"publisher","first-page":"1355","DOI":"10.4049\/jimmunol.2000338","article-title":"Identification of a protective leishmania antigen dihydrolipoyl dehydrogenase and its responding CD4(+) t cells at clonal level.","volume":"205","author":"Mou","year":"2020","journal-title":"J. Immunol."},{"key":"B22","doi-asserted-by":"publisher","first-page":"126476","DOI":"10.1016\/j.vaccine.2024.126476","article-title":"Pseudomonas aeruginosa elongation factor-tu (EF-tu) is an immunogenic protective protein antigen.","volume":"42","author":"Moustafa","year":"2024","journal-title":"Vaccine"},{"key":"B23","doi-asserted-by":"publisher","first-page":"160","DOI":"10.1016\/j.vaccine.2018.11.015","article-title":"Immunization with pneumococcal elongation factor tu enhances serotype-independent protection against streptococcus pneumoniae infection.","volume":"37","author":"Nagai","year":"2019","journal-title":"Vaccine"},{"key":"B24","doi-asserted-by":"publisher","first-page":"e1012686","DOI":"10.1371\/journal.ppat.1012686","article-title":"A surface lipoprotein on pasteurella multocida binds complement factor i to promote immune evasion.","volume":"21","author":"Nguyen","year":"2025","journal-title":"PLoS Pathog."},{"key":"B25","doi-asserted-by":"publisher","first-page":"3547","DOI":"10.4049\/jimmunol.1502339","article-title":"TNF-alpha and macrophages are critical for respiratory syncytial virus-induced exacerbations in a mouse model of allergic airways disease.","volume":"196","author":"Nguyen","year":"2016","journal-title":"J. Immunol."},{"key":"B26","doi-asserted-by":"publisher","first-page":"1261","DOI":"10.1016\/j.rvsc.2012.05.011","article-title":"Immunogenicity and protective efficacy of the recombinant pasteurella lipoprotein e and outer membrane protein h from pasteurella multocida a:3 in mice.","volume":"93","author":"Okay","year":"2012","journal-title":"Res. Vet. Sci."},{"key":"B27","doi-asserted-by":"publisher","first-page":"1","DOI":"10.1111\/j.1574-6968.1997.tb10401.x","article-title":"Secreted enzymes of aeromonas.","volume":"152","author":"Pemberton","year":"1997","journal-title":"FEMS Microbiol. Lett."},{"key":"B28","doi-asserted-by":"publisher","first-page":"85","DOI":"10.1016\/j.gene.2016.01.041","article-title":"Genomic characterization of pasteurella multocida HB01, a serotype a bovine isolate from china.","volume":"581","author":"Peng","year":"2016","journal-title":"Gene"},{"key":"B29","doi-asserted-by":"publisher","first-page":"167","DOI":"10.1016\/0378-1135(93)90170-c","article-title":"Protection of pasteurella multocida dermonecrotic toxin-challenged rats by toxoid-induced antibody.","volume":"34","author":"Pettit","year":"1993","journal-title":"Vet. Microbiol."},{"key":"B30","doi-asserted-by":"publisher","first-page":"1210","DOI":"10.3390\/pathogens12101210","article-title":"Pasteurella multocida infection in humans.","volume":"12","author":"Piorunek","year":"2023","journal-title":"Pathogens"},{"key":"B31","doi-asserted-by":"publisher","first-page":"e41","DOI":"10.1016\/S0140-6736(19)30953-5","article-title":"Dog licks baby. Baby gets pasteurella multocida meningitis.","volume":"393","author":"Ryan","year":"2019","journal-title":"Lancet"},{"key":"B32","doi-asserted-by":"publisher","first-page":"515","DOI":"10.1007\/s12088-011-0182-6","article-title":"Toxicity of crude extracellular products of aeromonas hydrophila on rohu, labeo rohita (ham.).","volume":"51","author":"Sahu","year":"2011","journal-title":"Indian J. Microbiol."},{"key":"B33","doi-asserted-by":"publisher","first-page":"2493","DOI":"10.1128\/aem.61.7.2493-2498.1995","article-title":"Analysis of antigens present in the extracellular products and cell surface of vibrio anguillarum serotypes o1, o2, and o3.","volume":"61","author":"Santos","year":"1995","journal-title":"Appl. Environ. Microbiol."},{"key":"B34","doi-asserted-by":"publisher","first-page":"384","DOI":"10.1111\/j.1472-765x.2009.02677.x","article-title":"Inhibition of frog antimicrobial peptides by extracellular products of the bacterial pathogen aeromonas hydrophila.","volume":"49","author":"Schadich","year":"2009","journal-title":"Lett. Appl. Microbiol."},{"key":"B35","doi-asserted-by":"publisher","first-page":"1","DOI":"10.1016\/j.rvsc.2014.11.013","article-title":"Recombinant transferrin binding protein a (rTbpA) fragments of pasteurella multocida serogroup b:2 provide variable protection following homologous challenge in mouse model.","volume":"98","author":"Shivachandra","year":"2015","journal-title":"Res. Vet. Sci."},{"key":"B36","doi-asserted-by":"publisher","first-page":"176","DOI":"10.1016\/j.fsi.2018.07.004","article-title":"Immunogenicity of extracellular products from an inactivated vaccine against aeromonas veronii TH0426 in koi, cyprinus carpio.","volume":"81","author":"Song","year":"2018","journal-title":"Fish Shellfish Immunol."},{"key":"B37","doi-asserted-by":"publisher","first-page":"960033","DOI":"10.3389\/fvets.2022.960033","article-title":"Investigation and analysis of etiology associated with porcine respiratory disease complex in china from 2017 to 2021.","volume":"9","author":"Sun","year":"2022","journal-title":"Front. Vet. Sci."},{"key":"B38","doi-asserted-by":"publisher","first-page":"2910","DOI":"10.3389\/fimmu.2018.02910","article-title":"EF-tu from non-typeable haemophilus influenzae is an immunogenic surface-exposed protein targeted by bactericidal antibodies.","volume":"9","author":"Thofte","year":"2018","journal-title":"Front. Immunol."},{"key":"B39","doi-asserted-by":"publisher","first-page":"104375","DOI":"10.1016\/j.micpath.2020.104375","article-title":"Development of novel iron-regulated pasteurella multocida b: 2 bacterin and refinement of vaccine quality in terms of minimum variation in particle size and distribution vis-a-vis critical level of iron in media.","volume":"147","author":"Varshney","year":"2020","journal-title":"Microb. Pathog."},{"key":"B40","doi-asserted-by":"publisher","first-page":"cm2","DOI":"10.1126\/scisignal.3105cm2","article-title":"Interleukin-1beta (IL-1beta) processing pathway.","volume":"3","author":"Weber","year":"2010","journal-title":"Sci. Signal."},{"key":"B41","doi-asserted-by":"publisher","first-page":"1561","DOI":"10.1128\/IAI.69.3.1561-1567.2001","article-title":"Recombinant neisseria meningitidis transferrin binding protein a protects against experimental meningococcal infection.","volume":"69","author":"West","year":"2001","journal-title":"Infect. Immun."},{"key":"B42","doi-asserted-by":"publisher","first-page":"1","DOI":"10.1007\/82_2012_216","article-title":"Pasteurella multocida: Diseases and pathogenesis.","volume":"361","author":"Wilkie","year":"2012","journal-title":"Curr. Top. Microbiol. Immunol."},{"key":"B43","doi-asserted-by":"publisher","first-page":"105426","DOI":"10.1016\/j.psj.2025.105426","article-title":"Evaluation of immunoprotective effects of PlpE multi-epitope protein incorporated within the aluminum hydroxide-adjuvanted inactivated vaccine against pasteurella multocida infection in chickens.","volume":"104","author":"Xiang","year":"2025","journal-title":"Poult. Sci."},{"key":"B44","doi-asserted-by":"publisher","first-page":"1001","DOI":"10.1016\/j.fsi.2022.07.046","article-title":"Immune enhancement effects of inactivated vaccine against extracellular products of aeromonas caviae AC-CY on crucian carp.","volume":"127","author":"Yuan","year":"2022","journal-title":"Fish Shellfish Immunol."},{"key":"B45","doi-asserted-by":"publisher","first-page":"765495","DOI":"10.3389\/fvets.2021.765495","article-title":"Genomic and transcriptomic analysis of bovine pasteurella multocida serogroup a strain reveals insights into virulence attenuation.","volume":"8","author":"Zhan","year":"2021","journal-title":"Front. Vet. Sci."},{"key":"B46","doi-asserted-by":"publisher","first-page":"270","DOI":"10.1016\/j.fsi.2013.11.015","article-title":"Vaccination of channel catfish with extracellular products of aeromonas hydrophila provides protection against infection by the pathogen.","volume":"36","author":"Zhang","year":"2014","journal-title":"Fish Shellfish Immunol."},{"key":"B47","doi-asserted-by":"publisher","first-page":"115","DOI":"10.1007\/5584_2016_198","article-title":"Immunization with streptococcal heme binding protein (shp) protects mice against group a streptococcus infection.","volume":"973","author":"Zhang","year":"2017","journal-title":"Adv. Exp. Med. Biol."},{"key":"B48","doi-asserted-by":"publisher","first-page":"31","DOI":"10.1186\/s13567-024-01285-y","article-title":"Pasteurella multocida activates rassf1-hippo-yap pathway to induce pulmonary epithelial apoptosis.","volume":"55","author":"Zhao","year":"2024","journal-title":"Vet. Res."},{"key":"B49","doi-asserted-by":"publisher","first-page":"17","DOI":"10.1186\/s13567-022-01035-y","article-title":"Immunogenicity and protection of a pasteurella multocida strain with a truncated lipopolysaccharide outer core in ducks.","volume":"53","author":"Zhao","year":"2022","journal-title":"Vet. Res."},{"key":"B50","doi-asserted-by":"publisher","first-page":"251","DOI":"10.2217\/fmb-2021-0112","article-title":"Significance of broad-spectrum racemases for the viability and pathogenicity of aeromonas hydrophila.","volume":"17","author":"Zhao","year":"2022","journal-title":"Future Microbiol."}],"container-title":["Frontiers in Microbiology"],"original-title":[],"link":[{"URL":"https:\/\/www.frontiersin.org\/articles\/10.3389\/fmicb.2025.1674831\/full","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,9,9]],"date-time":"2025-09-09T06:02:27Z","timestamp":1757397747000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.frontiersin.org\/articles\/10.3389\/fmicb.2025.1674831\/full"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2025,9,9]]},"references-count":50,"alternative-id":["10.3389\/fmicb.2025.1674831"],"URL":"https:\/\/doi.org\/10.3389\/fmicb.2025.1674831","relation":{},"ISSN":["1664-302X"],"issn-type":[{"value":"1664-302X","type":"electronic"}],"subject":[],"published":{"date-parts":[[2025,9,9]]},"article-number":"1674831"}}