{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,4,8]],"date-time":"2026-04-08T05:08:46Z","timestamp":1775624926989,"version":"3.50.1"},"reference-count":41,"publisher":"MDPI AG","issue":"7","license":[{"start":{"date-parts":[[2026,4,3]],"date-time":"2026-04-03T00:00:00Z","timestamp":1775174400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Animals"],"abstract":"<jats:p>The moderate pathogenicity coupled with high host susceptibility of Eimeria maxima has precipitated substantial economic losses in the poultry industry. Addressing challenges such as emerging drug resistance underscores the imperative for innovative vaccine strategies. This study developed a novel DNA vaccine to solve this challenge by fusing E. maxima elongation factor-1\u03b1 (EmEF1\u03b1) with chicken chemokine XCL1 (ChXCL1) in the pVAX1 vector. The recombinant plasmid, designated pVAX1-ChXCL1-EmEF1\u03b1, was successfully constructed and confirmed to express the ChXCL1-EmEF1\u03b1 fusion protein in vitro. Immunization of chickens with this DNA vaccine elicited a robust and balanced immune response, characterized by significantly increased proportions of CD4+ (11.76%) and CD8+ (5.58%) T lymphocytes, elevated levels of Th1-associated cytokines (IFN-\u03b3 and IL-12), and strong antigen-specific IgG and IgA antibody responses. Following experimental challenge with E. maxima, vaccinated birds exhibited substantial protection: a 66.4% reduction in oocyst shedding, a 71.7% improvement in relative weight gain, marked attenuation of intestinal lesions, and an anticoccidial index (ACI) of 170. These findings demonstrate that the ChXCL1-EmEF1\u03b1 DNA vaccine effectively enhances both cellular and humoral immunity. Collectively, this study validates ChXCL1 as a potent molecular adjuvant and establishes the \u201cantigen\u2013adjuvant\u201d fusion DNA platform as a promising strategy for developing next-generation vaccines against avian coccidiosis.<\/jats:p>","DOI":"10.3390\/ani16071108","type":"journal-article","created":{"date-parts":[[2026,4,6]],"date-time":"2026-04-06T00:19:32Z","timestamp":1775434772000},"page":"1108","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Evaluation of Immunoprotective Effects of DNA Vaccine Based on Eimeria maxima EF-1\u03b1 Antigen and Chicken XCL1 Chemokine"],"prefix":"10.3390","volume":"16","author":[{"given":"Xiao-Feng","family":"Lin","sequence":"first","affiliation":[{"name":"College of Animal Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Xi-Ge","family":"Wang","sequence":"additional","affiliation":[{"name":"College of Animal Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0009-0006-2833-5883","authenticated-orcid":false,"given":"Chang-Sheng","family":"Fu","sequence":"additional","affiliation":[{"name":"College of Animal Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Zhong-Sheng","family":"Zhang","sequence":"additional","affiliation":[{"name":"College of Animal Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Hai-Yan","family":"Wu","sequence":"additional","affiliation":[{"name":"College of Animal Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0009-0002-9806-6886","authenticated-orcid":false,"given":"Pan-Pan","family":"Guo","sequence":"additional","affiliation":[{"name":"College of Animal Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Deng-Feng","family":"Wang","sequence":"additional","affiliation":[{"name":"College of Animal Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Lei","family":"Wang","sequence":"additional","affiliation":[{"name":"College of Animal Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Yu-Tong","family":"Yan","sequence":"additional","affiliation":[{"name":"College of Animal Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-3129-0704","authenticated-orcid":false,"given":"Guang-Wen","family":"Yin","sequence":"additional","affiliation":[{"name":"College of Animal Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, China"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2026,4,3]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"115","DOI":"10.1186\/s13567-020-00837-2","article-title":"Re-calculating the cost of coccidiosis in chickens","volume":"51","author":"Blake","year":"2020","journal-title":"Vet. Res."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"1217","DOI":"10.3382\/ps.2013-03807","article-title":"Expression of digestive enzymes and nutrient transporters in Eimeria acervulina-challenged layers and broilers","volume":"93","author":"Su","year":"2014","journal-title":"Poult. Sci."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"102125","DOI":"10.1016\/j.psj.2022.102125","article-title":"The effects of xylo-oligosaccharides on regulating growth performance, nutrient utilization, gene expression of tight junctions, nutrient transporters, and cecal short chain fatty acids profile in Eimeria-challenged broiler chickens","volume":"101","author":"Lin","year":"2022","journal-title":"Poult. Sci."},{"key":"ref_4","doi-asserted-by":"crossref","unstructured":"MacDonald, S.E., Nolan, M.J., Harman, K., Boulton, K., Hume, D.A., Tomley, F.M., Stabler, R.A., and Blake, D.P. (2017). Effects of Eimeria tenella infection on chicken caecal microbiome diversity, exploring variation associated with severity of pathology. PLoS ONE, 12.","DOI":"10.1371\/journal.pone.0184890"},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"209","DOI":"10.1080\/03079457.2021.1912288","article-title":"Spotlight on avian pathology: Eimeria and the disease coccidiosis","volume":"20","author":"Blake","year":"2021","journal-title":"Avian Pathol."},{"key":"ref_6","first-page":"217","article-title":"Current status of anticoccidial drug resistance in China","volume":"37","author":"Bai","year":"2025","journal-title":"Chin. J. Schistosomiasis Control"},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"34111","DOI":"10.1074\/jbc.M113.515544","article-title":"Elongation Factor-1\u03b1 is a novel protein associated with host cell invasion and a potential protective antigen of Cryptosporidium parvum","volume":"288","author":"Matsubayashi","year":"2013","journal-title":"J. Biol. Chem."},{"key":"ref_8","first-page":"3111","article-title":"Preliminary study on the function of Elongation Factor 1\u03b1 of Eimeria tenella","volume":"51","author":"Liang","year":"2020","journal-title":"Acta Veteribaria Et Zootech. Sin."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"79","DOI":"10.1016\/j.vetpar.2017.06.003","article-title":"Vaccination with Eimeria tenella elongation factor-1\u03b1 recombinant protein induces protective immunity against E. tenella and E. maxima infections","volume":"243","author":"Lin","year":"2017","journal-title":"Vet. Parasitol."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"102013","DOI":"10.1016\/j.psj.2022.102013","article-title":"Co-administration of chicken IL-7 or NK-lysin peptide 2 enhances the efficacy of Eimeria elongation factor-1\u03b1 vaccination against Eimeria maxima infection in broiler chickens","volume":"101","author":"Lee","year":"2022","journal-title":"Poult. Sci."},{"key":"ref_11","doi-asserted-by":"crossref","unstructured":"Chen, R., Lin, X.F., Wu, H.Y., Li, L.N., Wang, L., Wang, D.F., Wu, H.Y., Guo, P.P., Mohsin, M., and Yin, G.W. (2025). Synergistic enhancement of Eimeria maxima vaccine efficacy through EF-1\u03b1 antigen and chicken XCL1 chemokine adjuvant combination. Animals, 15.","DOI":"10.3390\/ani15162330"},{"key":"ref_12","doi-asserted-by":"crossref","unstructured":"Lee, Y., Park, I., Wickramasuriya, S.S., and Lillehoj, H.S. (2023). Bacillus subtilis expressing chicken NK-2 peptide enhances the efficacy of EF-1\u03b1 Vaccination in Eimeria maxima-challenged broiler chickens. Animals, 13.","DOI":"10.3390\/ani13081383"},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"2205","DOI":"10.1182\/blood.V97.8.2205","article-title":"The C-class chemokine lymphotactin costimulates the apoptosis of human CD4+ T cells","volume":"97","author":"Cerdan","year":"2001","journal-title":"Blood"},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"1283","DOI":"10.1084\/jem.20100223","article-title":"The XC chemokine receptor 1 is a conserved selective marker of mammalian cells homologous to mouse CD8\u03b1+ dendritic cells","volume":"207","author":"Crozat","year":"2010","journal-title":"J. Exp. Med."},{"key":"ref_15","doi-asserted-by":"crossref","unstructured":"Matsuo, K., Kitahata, K., Kawabata, F., Kamei, M., Hara, Y., Takamura, S., Oiso, N., Kawada, A., Yoshie, O., and Nakayama, T. (2018). A Highly active form of XCL1\/Lymphotactin functions as an effective adjuvant to recruit cross-presenting dendritic cells for induction of effector and memory CD8+ T cells. Front. Immunol., 9.","DOI":"10.3389\/fimmu.2018.02775"},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"624","DOI":"10.1002\/eji.201445080","article-title":"Vaccine molecules targeting Xcr1 on cross-presenting DCs induce protective CD8+ T cell responses against Influenza virus","volume":"45","author":"Fossum","year":"2015","journal-title":"Eur. J. Immunol."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"1820","DOI":"10.1038\/s41598-018-38080-7","article-title":"Dendritic cell targeted Ccl3- and Xcl1-fusion DNA vaccines differ in induced immune responses and optimal delivery site","volume":"9","author":"Braathen","year":"2019","journal-title":"Sci. Rep."},{"key":"ref_18","doi-asserted-by":"crossref","unstructured":"Sun, Z.J., Wu, Z.Y., and Su, X.C. (2025). Developing an effective therapeutic HPV vaccine to eradicate large tumors by genetically fusing Xcl1 and incorporating IL-9 as molecular adjuvants. Vaccines, 13.","DOI":"10.3390\/vaccines13010049"},{"key":"ref_19","first-page":"4047","article-title":"Cloning and bioinformatics analysis of XCL1 gene CDS in Gushi chicken","volume":"48","author":"Tian","year":"2021","journal-title":"China Anim. Husb. Vet. Med."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"267","DOI":"10.1016\/S0264-410X(01)00270-5","article-title":"Adjuvant effects of IL-1beta, IL-2, IL-8, IL-15, IFN-alpha, IFN-gamma TGF-beta4 and lymphotactin on DNA vaccination against Eimeria acervulina","volume":"20","author":"Min","year":"2001","journal-title":"Vaccines"},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"171","DOI":"10.1111\/imm.13426","article-title":"Development of novel reagents to chicken FLT3, XCR1 and CSF2R for the identification and characterization of avian conventional dendritic cells","volume":"165","author":"Wu","year":"2021","journal-title":"Immunology"},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"518","DOI":"10.1080\/00071668.2020.1759787","article-title":"Efficacy of recombinant N- and C-terminal derivative of EmIMP1 against E. maxima infection in chickens","volume":"61","author":"Chen","year":"2020","journal-title":"Br. Poult. Sci."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"1861","DOI":"10.1007\/s00436-021-07105-y","article-title":"Evaluation of immunoprotective effects of recombinant protein and DNA vaccine based on Eimeria tenella surface antigen 16 and 22 in vivo","volume":"120","author":"Zhao","year":"2021","journal-title":"Parasitol. Res."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"235","DOI":"10.1007\/s00436-021-07364-9","article-title":"Evaluation of immunoprotective effects of recombinant proteins and DNA vaccines derived from Eimeria tenella surface antigen 6 and 15 in vivo","volume":"121","author":"Geng","year":"2021","journal-title":"Parasitol. Res."},{"key":"ref_25","doi-asserted-by":"crossref","unstructured":"Krzysica, P., Verhoog, L., de Vries, S., Smits, C., Savelkoul, H.F.J., and Tijhaar, E. (2022). Optimization of Capture ELISAs for Chicken Cytokines Using Commercially Available Antibodies. Animals, 12.","DOI":"10.3390\/ani12213040"},{"key":"ref_26","doi-asserted-by":"crossref","unstructured":"Wang, L., Guo, W.Z., Haq, S.U., Guo, Z.T., Cui, D.A., Yang, F., Cheng, F., Wei, X.J., and Lv, J.W. (2021). Anticoccidial activity of qinghao powder against Eimeria tenella in broiler chickens. Front. Vet. Sci., 8.","DOI":"10.3389\/fvets.2021.709046"},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"30","DOI":"10.1016\/0014-4894(70)90063-9","article-title":"Anticoccidial drugs: Lesion scoring techniques in battery and floor-pen experiments with chickens","volume":"28","author":"Johnson","year":"1970","journal-title":"Exp. Parasitol."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"233","DOI":"10.1016\/j.vetpar.2005.11.024","article-title":"Counting coccidial oocysts in chicken faeces: A comparative study of a standard McMaster technique and a new rapid method","volume":"136","author":"Haug","year":"2006","journal-title":"Vet. Parasitol."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"3870902","DOI":"10.1155\/2020\/3870902","article-title":"Efficacy of an oral solution prepared from the ultrasonic extract of radix dichroae roots against Eimeria tenella in broiler chickens","volume":"2020","author":"Wang","year":"2020","journal-title":"Evid.-Based Complement. Altern. Med."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"601","DOI":"10.1007\/s00436-010-1901-3","article-title":"Anticoccidial activity of maslinic acid against infection with Eimeria tenella in chickens","volume":"107","author":"Montero","year":"2010","journal-title":"Parasitol. Res."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"1141","DOI":"10.1016\/S0020-7519(98)00024-1","article-title":"Evaluation of the efficacy of anticoccidial drugs against Eimeria species in the fowl","volume":"28","author":"Chapman","year":"1998","journal-title":"Int. J. Parasitol."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"336","DOI":"10.1093\/ps\/79.3.336","article-title":"Responses of chickens to a recombinant refractile body antigen of Eimeria tenella administered using various immunizing strategies","volume":"79","author":"Kopko","year":"2000","journal-title":"Poult. Sci."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"2764","DOI":"10.1016\/j.vaccine.2015.04.052","article-title":"Induction of protective immunity against Eimeria tenella, Eimeria necatrix, Eimeria maxima and Eimeria acervulina infections using multivalent epitope DNA vaccines","volume":"33","author":"Song","year":"2015","journal-title":"Vaccine"},{"key":"ref_34","doi-asserted-by":"crossref","unstructured":"Kim, W.H., Chaudhari, A.A., and Lillehoj, H.S. (2019). Involvement of T cell immunity in avian coccidiosis. Front. Immunol., 10.","DOI":"10.3389\/fimmu.2019.02732"},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"259","DOI":"10.1016\/j.vetimm.2006.08.006","article-title":"Changes in immune-related gene expression and intestinal lymphocyte subpopulations following Eimeria maxima infection of chickens","volume":"114","author":"Hong","year":"2006","journal-title":"Vet. Immunol. Immunopathol."},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"e70032","DOI":"10.1002\/pro.70032","article-title":"The multifaceted role of XCL1 in health and disease","volume":"34","author":"Syed","year":"2025","journal-title":"Protein Sci."},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"5331","DOI":"10.1016\/j.psj.2020.07.028","article-title":"In vitro effects of 5 recombinant antigens of Eimeria maxima on maturation, differentiation, and immunogenic functions of dendritic cells derived from chicken spleen","volume":"99","author":"Haseeb","year":"2020","journal-title":"Poult. Sci."},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"307","DOI":"10.2307\/1592481","article-title":"Recombinant chicken interferon-gamma-mediated inhibition of Eimeria tenella development in vitro and reduction of oocyst production and body weight loss following Eimeria acervulina challenge infection","volume":"42","author":"Lillehoj","year":"1998","journal-title":"Avian Dis."},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"430","DOI":"10.3382\/ps\/pev365","article-title":"Interleukin-10 neutralizing antibody for detection of intestinal luminal levels and as a dietary additive in Eimeria challenged broiler chicks","volume":"95","author":"Arendt","year":"2016","journal-title":"Poult. Sci."},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"392","DOI":"10.1016\/0167-5699(95)80008-5","article-title":"IgY: Clues to the origins of modern antibodies","volume":"16","author":"Warr","year":"1995","journal-title":"Immunol. Today"},{"key":"ref_41","doi-asserted-by":"crossref","first-page":"77","DOI":"10.1016\/j.vetpar.2013.01.013","article-title":"Meta-analysis of the performance variation in broilers experimentally challenged by Eimeria spp.","volume":"196","author":"Kipper","year":"2013","journal-title":"Vet. Parasitol."}],"container-title":["Animals"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2076-2615\/16\/7\/1108\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,4,8]],"date-time":"2026-04-08T04:36:30Z","timestamp":1775622990000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2076-2615\/16\/7\/1108"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,4,3]]},"references-count":41,"journal-issue":{"issue":"7","published-online":{"date-parts":[[2026,4]]}},"alternative-id":["ani16071108"],"URL":"https:\/\/doi.org\/10.3390\/ani16071108","relation":{},"ISSN":["2076-2615"],"issn-type":[{"value":"2076-2615","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,4,3]]}}}