{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,19]],"date-time":"2026-09-19T18:57:54Z","timestamp":1789844274838,"version":"4.0.1"},"reference-count":51,"publisher":"MDPI AG","issue":"8","license":[{"start":{"date-parts":[[2021,8,1]],"date-time":"2021-08-01T00:00:00Z","timestamp":1627776000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Vaccines"],"abstract":"<jats:p>Lactococcus garvieae (L. garvieae) is an important pathogen that causes enormous economic losses in both marine and freshwater aquaculture. At present, antibiotics are the only option for farmers to reduce the losses caused by L. garvieae. However, the usage of antibiotics leads to environmental pollution and the production of drug-resistant strains of bacteria. Therefore, vaccination is preferred as an alternative method to prevent infectious diseases. In this study, we describe an effective approach to the production of an oral biofilm vaccine, using bacteria grown on chitosan particles to form biofilms, and thus providing an inactive pathogen that enhances the immune response in fish. We observed the formation of a biofilm on chitosan particles and administered the novel oral biofilm vaccine to fish. We analyzed the immune responses, including antibody production, phagocytic ability, albumin\/globulin ratio and immune-related genes, of vaccinated and control groups of black mullet. Our results show that the phagocytic ability of the biofilm vaccine group was 84%, which is significantly higher than that of the control group, and the antibody production in this group was significantly higher compared with the other group. The mRNA expression levels of immune-related genes (TLR2, IL-1\u03b2, TNF-\u03b1) were significantly upregulated in the spleen after vaccination. In challenge experiments, the relative percent survival (RPS) was 77% in the biofilm vaccine group, 18% in the whole-cell vaccine group, and 0% in the chitosan particle group at 32 days post-vaccination. In addition, we also found that the relative percent survival (RPS) at 1 day post-vaccination was 74% in the biofilm vaccine group, 42% in the whole-cell vaccine group, and 26% in the chitosan particle group. In both long-term and short-term challenge experiments, the viability of the biofilm vaccine group was significantly higher than that of the whole-cell, chitosan particle and PBS groups. We conclude that based on its protective effect, the L. garvieae biofilm vaccine is better than the whole-cell vaccine when challenged several weeks after vaccination. In addition, the biofilm vaccine also has a greater protective effect than the whole-cell vaccine when challenged immediately after vaccination. Therefore, the biofilm vaccine might represent a novel method for the prevention and treatment of L. garvieae infection.<\/jats:p>","DOI":"10.3390\/vaccines9080844","type":"journal-article","created":{"date-parts":[[2021,8,1]],"date-time":"2021-08-01T21:46:44Z","timestamp":1627854404000},"page":"844","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":26,"title":["Protective Efficacy of Novel Oral Biofilm Vaccines against Lactococcus garvieae Infection in Mullet, Mugil cephalus"],"prefix":"10.3390","volume":"9","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-6922-5764","authenticated-orcid":false,"given":"Feng-Jie","family":"Su","sequence":"first","affiliation":[{"name":"Department of Veterinary Medicine, National Taiwan University, No. 1, Section 4, Roosevelt Road, Taipei 10617, Taiwan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Meei-Mei","family":"Chen","sequence":"additional","affiliation":[{"name":"Department of Veterinary Medicine, National Taiwan University, No. 1, Section 4, Roosevelt Road, Taipei 10617, Taiwan"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2021,8,1]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"177","DOI":"10.1016\/j.cimid.2006.06.003","article-title":"Lactococcus garvieae in fish: A review","volume":"29","author":"Vendrell","year":"2006","journal-title":"Comp. Immunol. Microbiol. Infect. Dis."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"943","DOI":"10.1111\/j.1365-2761.2009.01075.x","article-title":"First isolation and characterization of Lactococcus garvieae from Brazilian Nile tilapia, Oreochromis niloticus (L.), and pintado, Pseudoplathystoma corruscans (Spix & Agassiz)","volume":"32","author":"Evans","year":"2009","journal-title":"J. Fish Dis."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"727","DOI":"10.1046\/j.1365-2761.2002.00415.x","article-title":"Lactococcus garvieae, a cause of disease in grey mullet, Mugil cephalus L., in Taiwan","volume":"25","author":"Chen","year":"2002","journal-title":"J. Fish Dis."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"677","DOI":"10.1146\/annurev.micro.57.030502.090720","article-title":"Bacterial Biofilms: An Emerging Link to Disease Pathogenesis","volume":"57","author":"Parsek","year":"2003","journal-title":"Annu. Rev. Microbiol."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"359","DOI":"10.3389\/fmicb.2018.00359","article-title":"Immune evasion mechanisms of Staphylococcus epidermidis biofilm infection","volume":"9","author":"Le","year":"2018","journal-title":"Front. Microbiol."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"193","DOI":"10.1016\/bs.pmbts.2016.05.007","article-title":"Host responses to biofilm","volume":"142","author":"Watters","year":"2016","journal-title":"Prog. Mol. Biol. Transl. Sci."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"245","DOI":"10.1186\/1471-2180-11-245","article-title":"Biofilm and planktonic pneumococci demonstrate disparate immunoreactivity to human convalescent sera","volume":"11","author":"Sanchez","year":"2011","journal-title":"BMC Microbiol."},{"key":"ref_8","doi-asserted-by":"crossref","unstructured":"Loera-Muro, A., Guerrero-Barrera, A., Tremblay DN, Y., Hathroubi, S., and Angulo, C.J.E.R.o.V. (2021). Bacterial biofilm-derived antigens: A new strategy for vaccine development against infectious diseases. Expert Rev. Vaccines, 1\u201315.","DOI":"10.1080\/14760584.2021.1892492"},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"37","DOI":"10.1016\/S0168-1656(00)00296-0","article-title":"Vaccine potential of poly-1-6 \u03b2-DN-succinylglucosamine, an immunoprotective surface polysaccharide of Staphylococcus aureus and Staphylococcus epidermidis","volume":"83","author":"Mckenney","year":"2000","journal-title":"J. Biotechnol."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"6148","DOI":"10.1016\/j.vaccine.2016.11.001","article-title":"Immunization with LytB protein of Streptococcus pneumoniae activates complement-mediated phagocytosis and induces protection against pneumonia and sepsis","volume":"34","author":"Corsini","year":"2016","journal-title":"Vaccine"},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"S41","DOI":"10.1079\/BJN20041356","article-title":"The role of gut-associated lymphoid tissues and mucosal defence","volume":"93","author":"Forchielli","year":"2005","journal-title":"Br. J. Nutr."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"103","DOI":"10.3354\/dao043103","article-title":"Uptake and processing of biofilm and free-cell vaccines of Aeromonas hydrophila in Indian major carps and common carp following oral vaccination antigen localization by a monoclonal antibody","volume":"43","author":"Azad","year":"2000","journal-title":"Dis. Aquat. Org."},{"key":"ref_13","first-page":"57","article-title":"Bacterial biofilms as oral vaccine candidates in aquaculture","volume":"37","author":"Vinay","year":"2016","journal-title":"Indian J. Comp. Microbiol. Immunol. Infect. Dis."},{"key":"ref_14","doi-asserted-by":"crossref","unstructured":"Rombout, J., and Kiron, V.J.F.v. (2014). Mucosal vaccination of fish. Fish Vaccination, Blackwell.","DOI":"10.1002\/9781118806913.ch6"},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"519","DOI":"10.1006\/fsim.1998.0206","article-title":"Biofilm vaccine of Aeromonas hydrophila\u2013standardization of dose and duration for oral vaccination of carps","volume":"9","author":"Azad","year":"1999","journal-title":"Fish Shellfish. Immunol."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"613","DOI":"10.1016\/j.fsi.2003.09.012","article-title":"Evaluation of biofilm of Aeromonas hydrophila for oral vaccination of Clarias batrachus\u2014A carnivore model","volume":"16","author":"Nayak","year":"2004","journal-title":"Fish Shellfish. Immunol."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"132","DOI":"10.1016\/j.fsi.2021.04.019","article-title":"Identification of novel vaccine candidates in the whole-cell Aeromonas hydrophila biofilm vaccine through reverse vaccinology approach","volume":"114","author":"Kaur","year":"2021","journal-title":"Fish Shellfish. Immunol."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"817","DOI":"10.1007\/s10499-019-00372-8","article-title":"Streptococcosis in Oreochromis sp.: Is feed-based biofilm vaccine of Streptococcus agalactiae effective?","volume":"27","author":"Kahieshesfandiari","year":"2019","journal-title":"Aquac. Int."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"746","DOI":"10.1016\/j.fsi.2019.09.053","article-title":"Evaluation of biofilm of Vibrio anguillarum for oral vaccination of Asian seabass, Lates calcarifer (BLOCH, 1790)","volume":"94","author":"Ram","year":"2019","journal-title":"Fish Shellfish. Immunol."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"81","DOI":"10.1016\/j.fsi.2021.02.017","article-title":"Modulation of the mucosal immune response of red tilapia (Oreochromis sp.) against columnaris disease using a biomimetic-mucoadhesive nanovaccine","volume":"112","author":"Kitiyodom","year":"2021","journal-title":"Fish Shellfish. Immunol."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"213","DOI":"10.1016\/j.fsi.2019.09.064","article-title":"Enhanced efficacy of immersion vaccination in tilapia against columnaris disease by chitosan-coated \u201cpathogen-like\u201d mucoadhesive nanovaccines","volume":"95","author":"Kitiyodom","year":"2019","journal-title":"Fish Shellfish. Immunol."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"983","DOI":"10.1128\/JCM.36.4.983-985.1998","article-title":"Identification of Lactococcus garvieae by PCR","volume":"36","author":"Zlotkin","year":"1998","journal-title":"J. Clin. Microbiol."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"210","DOI":"10.1016\/j.fsi.2020.01.016","article-title":"Effects of dietary chitosan and nano-chitosan loaded clinoptilolite on growth and immune responses of rainbow trout (Oncorhynchus mykiss)","volume":"98","author":"Oushani","year":"2020","journal-title":"Fish Shellfish. Immunol."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"249","DOI":"10.1111\/j.1472-765X.2007.02298.x","article-title":"A new colorimetric microtitre model for the detection of Staphylococcus aureus biofilms","volume":"46","author":"Tote","year":"2007","journal-title":"Lett. Appl. Microbiol."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"135","DOI":"10.1016\/0044-8486(95)01224-9","article-title":"Enhanced resistance against Edwardsiella tarda infection in tilapia (Oreochromis niloticus) by administration of protein-bound polysaccharide","volume":"143","author":"Park","year":"1996","journal-title":"Aquaculture"},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"45","DOI":"10.3354\/dao02581","article-title":"Vaccination strategies to protect goldfish Carassius auratus against Aeromonas hydrophila infection","volume":"104","author":"Deepa","year":"2013","journal-title":"Dis. Aquat. Org."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"593","DOI":"10.1016\/j.fsi.2016.10.006","article-title":"Transcriptome analysis of grey mullet (Mugil cephalus) after challenge with Lactococcus garvieae","volume":"58","author":"Byadgi","year":"2016","journal-title":"Fish Shellfish. Immunol."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"448","DOI":"10.1128\/iai.63.2.448-455.1995","article-title":"A pneumolysin-negative mutant of Streptococcus pneumoniae causes chronic bacteremia rather than acute sepsis in mice","volume":"63","author":"Benton","year":"1995","journal-title":"Infect. Immun."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"135","DOI":"10.1016\/S0140-6736(01)05321-1","article-title":"Antibiotic resistance of bacteria in biofilms","volume":"358","author":"Stewart","year":"2001","journal-title":"Lancet"},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"6585","DOI":"10.4049\/jimmunol.1002794","article-title":"Staphylococcus aureus biofilms prevent macrophage phagocytosis and attenuate inflammation in vivo","volume":"186","author":"Thurlow","year":"2011","journal-title":"J. Immunol."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"435","DOI":"10.1146\/annurev.mi.41.100187.002251","article-title":"Bacterial biofilms in nature and disease","volume":"41","author":"Costerton","year":"1987","journal-title":"Annu. Rev. Microbiol."},{"key":"ref_32","first-page":"257","article-title":"Adjuvants and immunostimulants for enhancing vaccine potency in fish","volume":"90","author":"Anderson","year":"1997","journal-title":"Dev. Boil. Stand."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"353","DOI":"10.3109\/08820139209069375","article-title":"Effectiveness of an oral enteric coated vibrio vaccine for use in salmonid fish","volume":"21","author":"Wong","year":"1992","journal-title":"Immunol. Investig."},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"167","DOI":"10.1006\/fsim.1994.1016","article-title":"The effects of different adjuvants on intestinal antigen absorption and subsequent immune responses of the tilapian Oreochromis mossambicus","volume":"4","author":"Jenkins","year":"1994","journal-title":"Fish Shellfish. Immunol."},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"373","DOI":"10.1016\/0145-305X(93)90008-E","article-title":"Route of immunization influences the generation of antibody secreting cells in the gut of rainbow trout (Oncorhynchus mykiss)","volume":"17","author":"Davidson","year":"1993","journal-title":"Dev. Comp. Immunol."},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"87","DOI":"10.1111\/j.1365-2109.2012.03207.x","article-title":"Efficacy of feed-based adjuvant vaccine against Streptococcus agalactiae in Oreochromis spp. in Malaysia","volume":"45","author":"Yusoff","year":"2013","journal-title":"Aquac. Res."},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"1740","DOI":"10.1016\/j.fsi.2013.02.029","article-title":"Adjuvants and immunostimulants in fish vaccines: Current knowledge and future perspectives","volume":"35","author":"Tafalla","year":"2013","journal-title":"Fish Shellfish. Immunol."},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"220","DOI":"10.1016\/j.vetimm.2008.07.002","article-title":"Chitosan microspheres as candidate plasmid vaccine carrier for oral immunisation of Japanese flounder (Paralichthys olivaceus)","volume":"126","author":"Tian","year":"2008","journal-title":"Veter- Immunol. Immunopathol."},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"1256","DOI":"10.1016\/j.dci.2011.03.007","article-title":"Advances in fish vaccine delivery","volume":"35","author":"Plant","year":"2011","journal-title":"Dev. Comp. Immunol."},{"key":"ref_40","doi-asserted-by":"crossref","unstructured":"Siripornadulsil, S., Dabrowski, K., and Sayre, R. (2007). Microalgal vaccines. Transgenic microalgae as green cell factories. Transgenic Microalgae as Green Cell Factories, Springer.","DOI":"10.1007\/978-0-387-75532-8_11"},{"key":"ref_41","doi-asserted-by":"crossref","first-page":"e00555","DOI":"10.1016\/j.btre.2020.e00555","article-title":"Isolation and characterization of Lactococcus garvieae from the fish gut for in vitro fermentation with carbohydrates from agro-industrial waste","volume":"28","author":"Patel","year":"2020","journal-title":"Biotechnol. Rep."},{"key":"ref_42","doi-asserted-by":"crossref","first-page":"983","DOI":"10.1111\/are.12050","article-title":"Effect of dietary chitosan on haematology, innate immunity and disease resistance of Asian seabass Lates calcarifer (Bloch)","volume":"45","author":"Ranjan","year":"2014","journal-title":"Aquac. Res."},{"key":"ref_43","doi-asserted-by":"crossref","first-page":"380","DOI":"10.1016\/j.fsi.2014.09.022","article-title":"Toll-like receptor recognition of bacteria in fish: Ligand specificity and signal pathways","volume":"41","author":"Zhang","year":"2014","journal-title":"Fish Shellfish. Immunol."},{"key":"ref_44","doi-asserted-by":"crossref","first-page":"129","DOI":"10.1016\/j.fsi.2015.01.037","article-title":"Characterization and expression analysis of Toll-like receptor 2 gene in large yellow croaker, Larimichthys crocea","volume":"44","author":"Fan","year":"2015","journal-title":"Fish Shellfish. Immunol."},{"key":"ref_45","doi-asserted-by":"crossref","first-page":"375","DOI":"10.1006\/fsim.1999.0241","article-title":"Carp interleukin-1\u03b2 in the role of an immuno-adjuvant","volume":"10","author":"Yin","year":"2000","journal-title":"Fish Shellfish. Immunol."},{"key":"ref_46","doi-asserted-by":"crossref","first-page":"283","DOI":"10.1016\/j.immuni.2008.06.011","article-title":"Tumor necrosis factor signaling mediates resistance to mycobacteria by inhibiting bacterial growth and macrophage death","volume":"29","author":"Clay","year":"2008","journal-title":"Immunity"},{"key":"ref_47","doi-asserted-by":"crossref","first-page":"1579","DOI":"10.1111\/jfd.13260","article-title":"Efficacy of a formalin-inactivated Lactococcus garvieae vaccine in farmed grey mullet Mugil cephalus","volume":"43","author":"Rao","year":"2020","journal-title":"J. Fish Dis."},{"key":"ref_48","doi-asserted-by":"crossref","first-page":"519","DOI":"10.3389\/fimmu.2015.00519","article-title":"Oral Vaccination of Fish\u2014Antigen Preparations, Uptake, and Immune Induction","volume":"6","author":"Mutoloki","year":"2015","journal-title":"Front. Immunol."},{"key":"ref_49","doi-asserted-by":"crossref","first-page":"375","DOI":"10.1016\/j.fsi.2013.04.030","article-title":"Vaccination efficiency of surface antigens and killed whole cell of Pseudomonas putida in large yellow croaker (Pseudosciaena crocea)","volume":"35","author":"Mao","year":"2013","journal-title":"Fish Shellfish. Immunol."},{"key":"ref_50","doi-asserted-by":"crossref","first-page":"581","DOI":"10.1016\/j.fsi.2014.09.021","article-title":"Evaluation of biofilm of Aeromonas hydrophila for oral vaccination of Channa striatus","volume":"41","author":"Siriyappagouder","year":"2014","journal-title":"Fish Shellfish. Immunol."},{"key":"ref_51","doi-asserted-by":"crossref","first-page":"431","DOI":"10.1016\/j.fsi.2019.05.020","article-title":"Valuable method for production of oral vaccine by using alginate and chitosan against Lactococcus garvieae\/Streptococcus iniae in rainbow trout (Oncorhynchus mykiss)","volume":"90","author":"Halimi","year":"2019","journal-title":"Fish Shellfish. Immunol."}],"container-title":["Vaccines"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2076-393X\/9\/8\/844\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T06:38:51Z","timestamp":1760164731000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2076-393X\/9\/8\/844"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2021,8,1]]},"references-count":51,"journal-issue":{"issue":"8","published-online":{"date-parts":[[2021,8]]}},"alternative-id":["vaccines9080844"],"URL":"https:\/\/doi.org\/10.3390\/vaccines9080844","relation":{},"ISSN":["2076-393X"],"issn-type":[{"value":"2076-393X","type":"electronic"}],"subject":[],"published":{"date-parts":[[2021,8,1]]}}}