Fish & shellfish immunology最新文献

{"title":"TRIM22 in Litopenaeus vannamei activates Dorsal by accelerating Cactus's degradation to mediate antiviral immunity.","authors":"Xuanzheng Di, Hao Yang, Airong Lv, Xiaodi Wang, Ruiying Li, Ranran Wang, Bin Yin, Sheng Wang, Shaoping Weng, Chaozheng Li, Jianguo He, Haoyang Li","doi":"10.1016/j.fsi.2025.110573","DOIUrl":"10.1016/j.fsi.2025.110573","url":null,"abstract":"<p><p>Tripartite motif protein 22 (TRIM22), an interferon-inducible E3 ubiquitin ligase, mediates antiviral responses in mammals by regulating NF-κB signaling. However, its functional role in invertebrates remains unknown. This study characterizes a TRIM22 ortholog (LvTRIM22) in Pacific white shrimp (Litopenaeus vannamei) and elucidates its molecular mechanism against white spot syndrome virus (WSSV). Upon WSSV infection, LvTRIM22 was transcriptionally upregulated. Co-immunoprecipitation assays revealed that LvTRIM22 bound to LvCactus (an IκB homolog) and mediated its K48-linked polyubiquitination and proteasomal degradation. Dual-luciferase reporter assays demonstrated that LvTRIM22 activated the Toll4-Dorsal-AMPs axis, thereby inducing expression of LvALF1 and LvLYZ1, two antimicrobial peptides with potent anti-WSSV activity. Consistently, knockdown of LvTRIM22 suppressed LvALF1 and LvLYZ1 expression, elevated viral loads, and increased shrimp mortality. All in all, LvTRIM22 acts as a critical E3 ubiquitin ligase that degrades LvCactus to activate the Dorsal-AMPs axis, conferring antiviral immunity against WSSV. This work provides the first evidence of TRIM22-mediated NF-κB regulation in invertebrates and highlights its potential for molecular breeding of WSSV-resistant shrimp.</p>","PeriodicalId":12127,"journal":{"name":"Fish & shellfish immunology","volume":" ","pages":"110573"},"PeriodicalIF":3.9,"publicationDate":"2025-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144667509","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Dietary supplementation of Priestia sp. PPB30 attenuates intestinal colonization and inflammatory response induced by Aeromonas veronii in loach through interfering with the LuxS/AI-2 quorum sensing system.","authors":"Chao Gao, Wenqing Yang, Yuyang Duan, Wenfang Niu, Yuqi Wang, Mengyuan Qin, Yi Li","doi":"10.1016/j.fsi.2025.110576","DOIUrl":"10.1016/j.fsi.2025.110576","url":null,"abstract":"<p><p>Aeromonas veronii, a zoonotic opportunistic pathogen, has posed serious threats to both the aquaculture industry and human health. The quorum sensing (QS) system plays a crucial regulatory role in the expression of virulence factors in A. veronii. Quorum sensing inhibitors (QSIs) provide an alternative control method by disrupting bacterial QS-systems, thereby reducing pathogenicity and virulence without directly killing bacteria. This study primarily explored the interference effect of Priestia sp. PPB30 on the LuxS/AI-2 QS system of A. veronii Z12 and its impact on virulence factors. Screening through a bioluminescence assay revealed that strain PPB30 effectively reduced the levels of autoinducer-2 (AI-2) in A. veronii Z12 without affecting its growth. Following treatment with strain PPB30, significant changes in the expression of LuxS/AI-2 related genes in strain Z12 were observed, along with a reduction in biofilm formation and the expression of virulence factors, including adhesion, hemolysis, extracellular proteases, and motility. Moreover, strain PPB30 reduced the colonization of A. veronii Z12 in the intestines of loaches, but had no inhibitory effect on the colonization level of the LuxS/AI-2 system-deficient mutant strain Z12ΔluxS in the loach intestine. Additionally, we found that dietary supplementation with strain PPB30 effectively alleviated intestinal damage caused by A. veronii Z12 infection and mitigated the host' s inflammatory response. The research findings reveal that Priestia sp. PPB30, as a potential probiotic, offers a novel strategy for the prevention and control of aquaculture pathogens by disrupting the LuxS/AI-2 QS-system, thereby inhibiting the expression of virulence and intestinal colonization of A. veronii Z12.</p>","PeriodicalId":12127,"journal":{"name":"Fish & shellfish immunology","volume":" ","pages":"110576"},"PeriodicalIF":3.9,"publicationDate":"2025-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144667507","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effect of dissolved oxygen concentration changes on the ultrastructure of blood cells in Manila clam (Ruditapes philippinarum).","authors":"Liqing Zhou, Xinyue Jiang, Hongsu Yang, Jiale Li, Jinlong Yang, Xiujun Sun, Biao Wu, Zhihong Liu, Huawang Li","doi":"10.1016/j.fsi.2025.110570","DOIUrl":"10.1016/j.fsi.2025.110570","url":null,"abstract":"<p><p>Manila clam (Ruditapes philippinarum) inhabits environments in which dissolved oxygen (DO) concentrations are prone to changes. Hemocytes are important participants in shellfish immune responses and are sensitive to environmental changes. To investigate the effect of DO concentration changes on the ultrastructure of R. philippinarum hemocytes and provide parameters for healthy breeding and management of this species, three DO concentration change modes were designed: normoxia C treatment; normoxia followed by acute hypoxia for 24 h and acute reoxygenation for 4 h, and normoxia followed by chronic hypoxia for 48 h and then chronic reoxygenation for 8 h. Hemocytes were classified as amoebocytes (AMCs), secretory cells (SECs), thrombocytes (THCs), spherical cells (SPCs), and macrophage-like cells (MACs). Granules were present in AMC, SEC, and SPC cytoplasm, and were rarely observed in THCs and MACs. The granule function and number and morphology of various organelles differed among hemocyte types. SPCs lost their spherical structure and their intracellular ultrastructure was severely damaged, leading to apoptosis. AMCs and SECs also suffered ultrastructural damage and apoptosis. AMCs exhibited weak deformability, decreased ability to engulf and remove foreign substances, and decreased secretion ability of SECs. Acute hypoxia damaged the THC ultrastructure and acute reoxygenation triggered coagulation reactions. Chronic hypoxia and reoxygenation severely affected MAC morphology and ultrastructure. Effects of DO concentration changes on the ultrastructure and function of five hemocyte types in Manila clams were clarified, providing a cellular basis for revealing the response of Manila clams to DO concentration changes.</p>","PeriodicalId":12127,"journal":{"name":"Fish & shellfish immunology","volume":" ","pages":"110570"},"PeriodicalIF":3.9,"publicationDate":"2025-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144682242","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Exploring the use of righting time in predicting the immunological condition of echinoderms: A case study with the sea urchin Echinometra lucunter","authors":"Mariana F. Acipreste ,&nbsp;Annie Mercier ,&nbsp;Jean-François Hamel ,&nbsp;Vincenzo Arizza ,&nbsp;Mirella Vazzana ,&nbsp;Manuela Mauro ,&nbsp;Márcio R. Custódio ,&nbsp;Vinicius Queiroz","doi":"10.1016/j.fsi.2025.110907","DOIUrl":"10.1016/j.fsi.2025.110907","url":null,"abstract":"<div><div>Studies correlating behavior and health are common for vertebrates but are comparatively limited for invertebrates, particularly within the phylum Echinodermata. Behavioral studies in echinoderms are scarce, chiefly focusing on covering and righting behaviors. Given the lack of consensus on the meaning and potential use of the righting time in echinoderms, measured as the time necessary to return to a natural position after being overturned, the present work aimed to establish links between this behavior and reliable but invasive health indicators. Through an experimental infection with the yeast <em>Saccharomyces cerevisiae</em>, we assessed whether the righting time of the sea urchin <em>Echinometra lucunter</em> mirrored a distruption in cellular and humoral immune markers. Our hypothesis posited that for righting time to serve as a reliable health indicator, infected sea urchins should exhibit extended righting times to match any altered immunological responses, analyzed through cellular and humoral immune parameters. The results demonstrated clear alterations in the latter, including elevated total coelomocyte counts and increased proportions of phagocytes, alongside a decreased proportion of vibratile cells and reduced coelomocyte viability. Furthermore, all analyzed biochemical parameters—specifically total protein and echinochrome concentrations, and alkaline phosphatase activity—increased in yeast-infested animals. However, while the righting time of yeast-infected animals showed a tendency to be elevated compared to that of control animals, it did not significantly differ. Consequently, our findings indicate that righting time does not seem to be a sensitive proxy of the health status of <em>E. lucunter</em>, and its application as a stress marker or predictor of sublethal changes in health condition should be approached with caution in this and other echinoderms.</div></div>","PeriodicalId":12127,"journal":{"name":"Fish & shellfish immunology","volume":"167 ","pages":"Article 110907"},"PeriodicalIF":3.9,"publicationDate":"2025-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145216577","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The effect of acute heat stress on the Chinook salmon immune system and their ability to combat Vibrio anguillarum infection and mortality","authors":"Emily J. McKenzie ,&nbsp;Noah P. Rogozynski ,&nbsp;Tania Rodríguez-Ramos ,&nbsp;John W. Heath ,&nbsp;Brian Dixon","doi":"10.1016/j.fsi.2025.110905","DOIUrl":"10.1016/j.fsi.2025.110905","url":null,"abstract":"<div><div>The frequency, duration, and intensity of heatwaves in western Canada is expected to rise in the coming years, and as a result, shallow streams will also experience drastic temperature fluctuations. This poses a problem for salmonids as encountering high water temperatures may increase their susceptibility to infectious disease. An environmentally applicable mock heat shock was performed on juvenile Chinook salmon and their immunological responses were measured for 14 days afterwards. Chinook salmon also received an injection of live <em>Vibrio anguillarum</em> after heat shock to determine if heat rendered them immunocompromised to systemic bacterial infection. <em>il1b, il8, tnfa, il10, tgfb, hsp47, hsp70,</em> and <em>hsp90</em> transcripts were quantified by qPCR in the spleen, gills, and hindgut. Heat shock did not affect mortality rates due to vibriosis compared to controls. Additionally, heat shock mitigated the pro-inflammatory and anti-inflammatory responses needed to combat infection by initially upregulating <em>il1b, tnfa, il8,</em> and <em>il10,</em> then returning to control levels by three days post-infection. Transcripts of <em>hsp47</em> and <em>hsp90</em> were upregulated in response to both heat shock and <em>V. anguillarum</em>. This research reports the first HSP47 protein measurements in Chinook salmon in plasma, which did not differ between any treatment groups. Plasma cortisol and lactate concentrations significantly increased, then returned to basal levels 6-h post-heat shock. Altogether, these data indicate that the experimental heat shock had a positive preconditioning effect on Chinook salmon and provides new insights on the interactions between the host, environment, and pathogen over a 14-day period.</div></div>","PeriodicalId":12127,"journal":{"name":"Fish & shellfish immunology","volume":"167 ","pages":"Article 110905"},"PeriodicalIF":3.9,"publicationDate":"2025-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145211861","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Assessment of immune and pro-apoptotic functions of mitogen-activated protein kinase-interacting kinase 2 (MKNK2) in yellowtail clownfish (Amphiprion clarkii)","authors":"H.A.C.R. Hanchapola ,&nbsp;D.S. Liyanage ,&nbsp;W.K.M. Omeka ,&nbsp;Yasara Kavindi Kodagoda ,&nbsp;M.A.H. Dilshan ,&nbsp;D.C.G. Rodrigo ,&nbsp;G.A.N.P. Ganepola ,&nbsp;B.P.M. Vileka Jayamali ,&nbsp;Gaeun Kim ,&nbsp;Jeongeun Kim ,&nbsp;Qiang Wan ,&nbsp;Jihun Lee ,&nbsp;Jehee Lee","doi":"10.1016/j.fsi.2025.110904","DOIUrl":"10.1016/j.fsi.2025.110904","url":null,"abstract":"<div><div>Mitogen-activated protein kinase-interacting serine/threonine-protein kinase 2 (MKNK2) regulates protein synthesis by phosphorylating eukaryotic initiation factor 4E (<em>eIF4E</em>). In this study, we characterized the yellowtail clownfish (<em>Amphiprion clarkii) MKNK2</em> gene, <em>AcMKNK2</em>, by investigating its transcriptional responses and functional properties using different functional assays. The <em>AcMKNK2</em> gene contains a 1425 bp open reading frame encoding 467 amino acids. The protein has a predicted molecular weight of 53.25 kDa and an isoelectric point value of 6.10. Two conserved active motifs (²¹⁰ENIL²¹³ and ²²⁹DLG²³¹) and a protein kinase ATP binding site were identified in the AcMKNK2 amino acid sequence. The highest constitutive expression of <em>AcMKNK2</em> was found in muscle tissue under normal physiological conditions, while significant upregulation was observed under stimulations with polyinosinic:polycytidylic acid (poly(I:C)), lipopolysaccharide (LPS), and <em>Vibrio harveyi</em> in the blood, gill, and head kidney tissues. Subcellular localization analysis revealed that the AcMKNK2 protein is localized to the nucleus. Furthermore, AcMKNK2 overexpression increased the production of reactive oxygen species and the <em>Bax</em>/<em>Bcl-</em>2 mRNA expression ratio in fathead minnow cells exposed to H₂O₂, emphasizing the pro-apoptotic activities under oxidative stress conditions. Furthermore, RAW267.4 cells overexpressing <em>AcMKNK2</em> demonstrated a significant increase in the expression of M1 marker genes and NO production after LPS stimulation. Overall, these findings suggest that AcMKNK2 mediates cellular stress responses and regulates host immunity in yellowtail clownfish by driving pro-apoptotic pathways and enhancing pro-inflammatory mechanisms.</div></div>","PeriodicalId":12127,"journal":{"name":"Fish & shellfish immunology","volume":"167 ","pages":"Article 110904"},"PeriodicalIF":3.9,"publicationDate":"2025-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145211816","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Molecular characterization and expression analysis of the TRAF gene family in the fourfinger threadfin (Eleutheronema tetradactylum)","authors":"Linjuan Wang ,&nbsp;Yifei Pan ,&nbsp;Huijuan Zhang ,&nbsp;Minxuan Jin ,&nbsp;Anna Zheng ,&nbsp;Jingheng Lu ,&nbsp;Weibin Liu ,&nbsp;Jiandong Zhang ,&nbsp;Baogui Tang ,&nbsp;Jiansheng Huang ,&nbsp;Bei Wang ,&nbsp;Jing Li ,&nbsp;Zhongliang Wang","doi":"10.1016/j.fsi.2025.110906","DOIUrl":"10.1016/j.fsi.2025.110906","url":null,"abstract":"<div><div>Originally characterized as adapter proteins linking TNF receptors to downstream signaling cascades, tumor necrosis factor receptor-associated factors (TRAFs) have since been recognized as pivotal signal transducers for multiple receptor families, regulating diverse biological processes. To date, seven mammalian <em>TRAF</em> members (<em>TRAF1</em>-<em>7</em>) have been identified, with well-documented roles in mediating innate immune responses. However, the functional significance of <em>TRAFs</em> in the innate immunity of the fourfinger threadfin (<em>Eleutheronema tetradactylum</em>) remains poorly understood. In this study, we identified and characterized eight <em>TRAF</em> genes in <em>E. tetradactylum</em>, designated <em>EtTRAF2a</em>, <em>EtTRAF2b</em>, <em>EtTRAF2-like</em>, <em>EtTRAF3</em>, <em>EtTRAF4a</em>, <em>EtTRAF5</em>, <em>EtTRAF6</em>, and <em>EtTRAF7</em>. Comprehensive sequence analysis revealed structural features conserved, including a C-terminal MATH domain and an N-terminal RING domain in all EtTRAFs, whereas EtTRAF7 uniquely contained seven WD40 repeat domains in its C-terminal region. Tissue distribution profiling via quantitative real-time PCR (qPCR) demonstrated constitutive expression of all eight <em>EtTRAF</em> genes across eight healthy tissues (skin, liver, brain, gill, spleen, kidney, heart, and intestine), with notably higher transcript levels in the liver and gill. Furthermore, the lipopolysaccharide (LPS) challenge induced significant temporal modulation of <em>EtTRAF</em> expression patterns. Collectively, our systematic investigation of <em>TRAFs</em> in <em>E. tetradactylum</em> provides critical insights into their putative roles in innate immune defense against pathogens and establishes a framework for future functional studies on TRAF-mediated signaling in teleost fishes.</div></div>","PeriodicalId":12127,"journal":{"name":"Fish & shellfish immunology","volume":"167 ","pages":"Article 110906"},"PeriodicalIF":3.9,"publicationDate":"2025-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145206033","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Evolutionary analysis and immune-induced expression and m6A modification of RIPK1 and RIPK2 in the miiuy croaker","authors":"Qianru Xing ,&nbsp;Shang Geng ,&nbsp;Xing Lv ,&nbsp;Yuena Sun ,&nbsp;Tianjun Xu","doi":"10.1016/j.fsi.2025.110903","DOIUrl":"10.1016/j.fsi.2025.110903","url":null,"abstract":"<div><div>Receptor Interacting Protein Kinases (RIPKs), including RIPK1 and RIPK2, are key mediators of inflammatory signaling and inflammatory cell death. In this study, we identified the RIPK1 and RIPK2 genes in the miiuy croaker (<em>Miichthys miiuy</em>) and analyzed their evolutionary conservation and structural characteristics using bioinformatics approaches, highlighting their potential immune functions. Notably, research on the role of N6-methyladenosine (m⁶A) modification in regulating RIPKs remains limited. Here, methylated RNA immunoprecipitation sequencing (MeRIP-seq) revealed significant m⁶A enrichment near the stop codons of RIPK1 and RIPK2 of <em>Miichthys miiuy</em>, which was further confirmed by MeRIP-PCR. Expression analyses showed that RIPK1 and RIPK2 were markedly upregulated after poly(I:C) and LPS stimulation. Interestingly, poly(I:C) increased the m⁶A modification level of RIPK1, whereas LPS reduced the m⁶A level of RIPK2. Moreover, treatment with the methylation inhibitor cycloleucine further elevated their expression. These findings suggest that m⁶A modification may participate in fine-tuning the immune regulatory networks involving RIPK1 and RIPK2, potentially modulating their expression dynamics in response to diverse immune stimuli. This work provides valuable insights into the epigenetic regulation of RIPK family members and offers a foundation for exploring m⁶A-mediated control of fish innate immunity.</div></div>","PeriodicalId":12127,"journal":{"name":"Fish & shellfish immunology","volume":"167 ","pages":"Article 110903"},"PeriodicalIF":3.9,"publicationDate":"2025-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145181942","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Teleost HMGB1 paralogues mediate protective autophagy by interacting with NOD2 and ATG16L1 and activating ROS/Akt/mTOR pathway against Aeromonas hydrophila infection","authors":"Dan Wang,&nbsp;Linan Chen,&nbsp;Xiaoyu Ma,&nbsp;Zhe Wang,&nbsp;Hong Zhou","doi":"10.1016/j.fsi.2025.110902","DOIUrl":"10.1016/j.fsi.2025.110902","url":null,"abstract":"<div><div>As a multifunctional regulator, high mobility group box 1 (HMGB1) plays an important role in DNA transcription, autophagy, infection and inflammation in mammals based on its cellular localization. Unlike in mammals, some teleost has two HMGB1 paralogues, and the DNA-binding and pro-inflammatory functions of extracellular HMGB1 have been characterized in various fish species, but the functional role of intracellular HMGB1 in bacterial infection remains elusive. In this study, the inducible effect of <em>Aeromonas hydrophila</em> (<em>A. hydrophila</em>) on autophagy was identified by using the autophagy related gene 7 (<em>Atg7</em>)-knockdown Epithelioma papulosum cyprini (EPC) cells, where fish HMGB1 paralogues have been defined as the autophagy regulator in our previous study. Consistently, the HMGB1 paralogues were proved to mediate <em>A. hydrophila-</em>induced autophagy by knockout HMGB1 paralogues and using HMGB1 inhibitors in the same cells, and suggested the defensive role of HMGB1 paralogues against <em>A. hydrophila</em> infection. Mechanistically, in accordance with the findings that nucleotide-binding oligomerization domain 2 (NOD2) but not NOD1 was involved in <em>A. hydrophila</em>-induced autophagy, HMGB1 mediated autophagy by interaction with NOD2 and ATG16L1. In addition, transcriptomic and western blotting assays further uncovered that HMGB1 regulated <em>A. hydrophila</em>-induced autophagy potentially by the ROS/AKT/mTOR signaling pathway. Furthermore, the physiological importance of HMGB1-mediated autophagic mechanism was strengthened in the primary neutrophils of grass carp, in which a complete autophagy flux mediated by HMGB1 facilitated <em>A. hydrophila</em> clearance. Notably, two HMGB1 paralogues played the same role in aforementioned events. Taken together, the intracellular role of fish HMGB1 paralogues in the autophagic response to <em>A. hydrophila</em> infection provided new insights into the immunological function of fish HMGB1, and offered clues as to how fish can defend themselves against bacterial infection.</div></div>","PeriodicalId":12127,"journal":{"name":"Fish & shellfish immunology","volume":"167 ","pages":"Article 110902"},"PeriodicalIF":3.9,"publicationDate":"2025-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145181897","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Oral immunization with recombinant L. lactis expressing RGNNV capsid protein protects grouper against RGNNV infection","authors":"Xiaojing Hua ,&nbsp;Haoqi Du ,&nbsp;Yan Zhang ,&nbsp;Yanzhi Yu ,&nbsp;Yuanan Lu ,&nbsp;Xueqin Liu","doi":"10.1016/j.fsi.2025.110900","DOIUrl":"10.1016/j.fsi.2025.110900","url":null,"abstract":"<div><div>Nervous necrosis virus (NNV) is a highly pathogenic positive-sense RNA virus that causes substantial economic losses in global grouper aquaculture industry. Its capsid protein (CP) exhibits strong antigenicity properties and represents a promising immunogen for vaccine development. Among the four major NNV genotypes, Redspotted grouper nervous necrosis virus (RGNNV) is the most prevalent. Lactic Acid Bacteria (LAB) are attractive oral vaccine delivery platforms, capable of inducing both mucosal and systemic immune responses. In this study, <em>Lactococcus lactis</em> (<em>L. lactis</em>) expression system was used with lactose as a screening marker to produce the RGNNV-CP. We successfully constructed the recombinant strain pNZ8149-Usp45-CP/<em>L. lactis</em> NZ3900, and confirmed protein expression by the immunofluorescence assay (IFA) and western blotting. Grouper were orally immunized with this strain and then challenged with RGNNV to assess immune protection. The recombinant L. <em>lactis</em> demonstrated persistent colonization capacity in fish intestinal and enhanced mucosal barrier function, indicating safety for the host. Also, oral vaccination elicited strong neutralizing responses, with serum antibody titers peaking on day 28 post-immunization. Upregulation of immune-related genes in the brain, intestine, and visceral tissues further supported robust immune activation. Vaccinated fish showed reduced viral loads and lower mortality, confirming vaccine's efficacy. These findings highlight pNZ8149-Usp45-CP/<em>L. lactis</em> NZ3900 as a promising antibiotic-free oral vaccine candidate for protecting grouper against RGNNV.</div></div>","PeriodicalId":12127,"journal":{"name":"Fish & shellfish immunology","volume":"167 ","pages":"Article 110900"},"PeriodicalIF":3.9,"publicationDate":"2025-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145174308","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}