Fish & shellfish immunology最新文献

{"title":"CiLSM14Aa acts as a cytosolic dsRNA sensor to activate antiviral immunity against GCRV-II","authors":"Hui Jiang ,&nbsp;Chu Zhang ,&nbsp;Pengfei Li ,&nbsp;Yong-An Zhang ,&nbsp;Xiangmou Qin","doi":"10.1016/j.fsi.2026.111162","DOIUrl":"10.1016/j.fsi.2026.111162","url":null,"abstract":"<div><div>The innate immune system relies on pattern recognition receptors (PRRs) to detect viral pathogens and initiate antiviral responses. LSM14A, a conserved RNA-binding protein involved in mRNA metabolism, has recently emerged as a cytosolic nucleic acid sensor in vertebrates. However, its role in teleost immunity remains unclear. In this study, two LSM14A paralogs were identified in grass carp (<em>Ctenopharyngodon idella</em>), designated CiLSM14Aa and CiLSM14Ab, and their functions during infection with grass carp reovirus genotype II (GCRV-II) were investigated. Both CiLSM14Aa and CiLSM14Ab were significantly upregulated following GCRV-II infection or poly(I:C) stimulation. Overexpression of CiLSM14Aa or CiLSM14Ab inhibited GCRV-II replication and enhanced the expression of type I interferon and interferon-stimulated genes (ISGs). Further analysis revealed that CiLSM14Aa and CiLSM14Ab can form homodimers and heterodimers. Notably, only CiLSM14Aa demonstrated direct binding to double-stranded RNA (dsRNA), suggesting a specific role as a cytosolic dsRNA sensor. These results demonstrate the essential antiviral roles of CiLSM14A paralogs and reveal their contributions to the initiation of innate immune defenses against GCRV-II infection.</div></div>","PeriodicalId":12127,"journal":{"name":"Fish & shellfish immunology","volume":"171 ","pages":"Article 111162"},"PeriodicalIF":3.9,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146085048","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 role of VxrB in Vibrio harveyi and evaluation of a VxrB knock-out as a vaccine candidate","authors":"Yinhui Peng ,&nbsp;Xin Lu ,&nbsp;Ming Liu ,&nbsp;Shuo Hu ,&nbsp;Lulu Liu ,&nbsp;Renjie Li ,&nbsp;LuJia Yang ,&nbsp;Xiaohui Cai ,&nbsp;Shuanghu Cai","doi":"10.1016/j.fsi.2026.111186","DOIUrl":"10.1016/j.fsi.2026.111186","url":null,"abstract":"<div><div><em>Vibrio harveyi</em> is a major bacterial pathogen in marine aquaculture and can cause serious disease outbreaks in fish and invertebrates. Two-component systems help bacteria sense environmental change and adjust gene expression, including genes linked to virulence. <em>VxrB</em> is a response regulator that has been connected to virulence control in other <em>Vibrio</em> species, but its role in <em>V. harveyi</em> is not well defined. In this study, we deleted <em>VxrB</em> in a virulent <em>V. harveyi</em> strain and named the mutant VHΔ<em>VxrB</em>. We compared it with the wild-type strain (W-VH) using <em>in vitro</em> assays, gene expression analysis, and infection and vaccination tests in pearl gentian grouper. Deleting <em>VxrB</em> did not change cell morphology by Gram staining or scanning electron microscopy. However, VHΔ<em>VxrB</em> grew more slowly and showed reduced hemolytic activity, while swarming motility increased. RT-qPCR showed that <em>VxrB</em> deletion reduced expression of several virulence-associated genes and lowered expression of the type VI secretion system (T6SS) genes <em>hcp</em> and <em>vgrG</em>. In fish, VHΔ<em>VxrB</em> was less virulent than W-VH, with an LD50 of 1.45 × 10⁸ CFU/mL compared with 4.88 × 10⁷ CFU/mL for the wild type. We also tested VHΔ<em>VxrB</em> as a live attenuated vaccine. Vaccinated fish had higher survival after homologous challenge, with an RPS of 68.75%, and showed no obvious histopathological lesions. Vaccination increased spleen expression of <em>mhc-Iα</em>, <em>myd88</em>, and <em>il-10</em>. Together, these results show that <em>VxrB</em> supports virulence-related programs in <em>V. harveyi</em> and that VHΔ<em>VxrB</em> is a promising attenuated vaccine candidate for pearl gentian grouper.</div></div>","PeriodicalId":12127,"journal":{"name":"Fish & shellfish immunology","volume":"171 ","pages":"Article 111186"},"PeriodicalIF":3.9,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146124234","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 μ-class glutathione S-transferase (SbGSTμ) involved in immune defense and detoxification in the ark shell Scapharca broughtonii","authors":"Guangming Zhang ,&nbsp;Yonghuan Huang ,&nbsp;Zhuanzhuan Li ,&nbsp;Peizhen Ma ,&nbsp;Xiujun Sun ,&nbsp;Liqing Zhou ,&nbsp;Zhihong Liu ,&nbsp;Biao Wu","doi":"10.1016/j.fsi.2026.111188","DOIUrl":"10.1016/j.fsi.2026.111188","url":null,"abstract":"<div><div>Glutathione S-transferases (GSTs) constitute a superfamily of multifunctional detoxification isoenzymes that play essential roles in innate immunity. In this study, a μ-class <em>GST</em> gene was identified from <em>Scapharca broughtonii</em> (designated <em>SbGSTμ</em>) using the RACE approach. The full-length cDNA of <em>SbGSTμ</em> is 1040 bp and encodes a cytosolic protein of 215 amino acids. Sequence analysis revealed that <em>SbGSTμ</em> contains conserved structural features characteristic of the μ-class <em>GST</em> family, including an N-terminal thioredoxin-like domain with glutathione (GSH)-binding sites and a C-terminal domain harboring substrate-binding sites. Tissue distribution analysis showed that <em>SbGSTμ</em> is ubiquitously expressed across all examined tissues, with the highest expression level detected in the foot. Upon challenge with <em>Staphylococcus aureus</em> or <em>Vibrio anguillarum</em>, or exposure to Cu²⁺, <em>SbGSTμ</em> mRNA expression was significantly upregulated compared to controls. Recombinant <em>SbGSTμ</em> protein was successfully expressed in <em>Escherichia coli</em>, purified, and functionally characterized. The enzyme exhibited optimal activity at temperatures between 30 °C and 40 °C and at pH 7.4. Furthermore, benzo [a]pyrene exposure assays demonstrated the detoxification capacity of <em>SbGSTμ</em> through a significant reduction in 8-hydroxy-2′-deoxyguanosine (8-OHdG) levels. Collectively, these findings support the classical role of GSTs in xenobiotic detoxification while providing evidence for their involvement in immunological host defense mechanisms in the ark shell <em>S. broughtonii</em>.</div></div>","PeriodicalId":12127,"journal":{"name":"Fish & shellfish immunology","volume":"171 ","pages":"Article 111188"},"PeriodicalIF":3.9,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146131550","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":"Population-specific transcriptomics of Pacific oyster after exposure to a highly pathogenic, globally distributed virus","authors":"Bernarda Calla ,&nbsp;Neil F. Thompson ,&nbsp;Colleen A. Burge","doi":"10.1016/j.fsi.2026.111154","DOIUrl":"10.1016/j.fsi.2026.111154","url":null,"abstract":"<div><div>Disease outbreaks in marine invertebrates, particularly in cultivated species, have increased as stressful environmental conditions become more frequent. The Ostreid herpesvirus and its microvariants have caused substantial mortalities in Pacific oysters globally, heavily impacting aquaculture production in localities where the virus becomes established. This study investigates the molecular response of Pacific oysters to OsHV-1 μVar infection in two oyster populations: a population of Miyagi oysters, and a population of Midori oysters. Although viral infection elicited a general and significant up-regulation of antiviral defense transcripts that was very similar in both populations and that included RIG-I like receptors and the interferon-like pathway, gene-wise clustering analyses clearly differentiated both populations. Among differences between Midori and Miyagi were several immunity-related genes and histone-coding genes that indicated possible pre-transcriptional mechanisms of gene regulation influencing disease outcomes. Among other differences, genes encoding for viral sensing proteins (SAMD9 and NFX-1 zinc finger) showed higher basal and infection-induced expression in Midori, whereas Miyagi oysters exhibited greater up-regulation of ubiquitination pathways. We also compared the general response of Pacific oysters to different OsHV-1 μVars strains, concluding that there is no marked difference between the oyster response to a U.S. OsHV-1 μVar compared to an Australian μVar. These results are important for future work that focuses on developing Pacific oysters that are tolerant to OsHV-1 μVars and to develop additional management strategies to prevent the spread of this viral disease.</div></div>","PeriodicalId":12127,"journal":{"name":"Fish & shellfish immunology","volume":"171 ","pages":"Article 111154"},"PeriodicalIF":3.9,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146046006","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":"Characterization of Toll-like receptor 22 in striped catfish (Pangasianodon hypophthalmus): Recognition of Gram-positive and Gram-negative bacteria","authors":"Thanh-Tan Nguyen ,&nbsp;Hieu Tran-Van","doi":"10.1016/j.fsi.2026.111203","DOIUrl":"10.1016/j.fsi.2026.111203","url":null,"abstract":"<div><div>Toll-like receptor 22 (TLR22) in <em>Pangasianodon hypophthalmus</em> is a key component of the fish innate immune system, responsible for recognizing pathogen-associated molecular patterns (PAMPs). However, its bacterial recognition mechanisms remain largely unexplored, particularly in striped catfish. In this study, four recombinant subunits of TLR22 - TLR22 (LRR1-17), TLR22 (LRR1-13), TLR22 (LRR1-10), and TLR22 (LRR1-4) - were successfully produced in <em>Escherichia coli</em> SHuffle® T7 Express, and protein expression was confirmed via SDS-PAGE and Western blot analysis. Dot blot and ELISA assays were employed to evaluate bacterial-binding activity against <em>Escherichia coli</em>, <em>Aeromonas hydrophila</em>, <em>Streptococcus agalactiae</em>, and <em>Lactiplantibacillus plantarum</em>. Among the subunits, TLR22 (LRR1–4) exhibited the strongest binding affinity, particularly toward Gram-positive bacteria. Furthermore, pre-blocking bacterial peptidoglycan with mouse serum significantly reduced TLR22 (LRR1-4) binding, indicating a likely peptidoglycan-mediated interaction. These findings provide the first experimental evidence that striped catfish TLR22 can recognize both Gram-negative and Gram-positive bacteria, broadening current understanding of its ligand recognition spectrum. This study highlights the potential role of TLR22 in bacterial immune detection and establishes a foundation for further investigations into the molecular mechanisms of fish innate immunity.</div></div>","PeriodicalId":12127,"journal":{"name":"Fish & shellfish immunology","volume":"171 ","pages":"Article 111203"},"PeriodicalIF":3.9,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146164741","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":"Acetylation-mediated regulation of immune function and antibacterial activity of rhamnose-binding lectin in Pinctada fucata martensii","authors":"Qiyuan Zhang ,&nbsp;Runlin Lei ,&nbsp;Chuanjie Liu ,&nbsp;Haiying Liang ,&nbsp;Chaojie Li ,&nbsp;Zixi He","doi":"10.1016/j.fsi.2026.111200","DOIUrl":"10.1016/j.fsi.2026.111200","url":null,"abstract":"<div><div><em>Pinctada fucata martensii</em> is the primary pearl-producing bivalve species in China. However, immune rejection following transplantation reduces pearl formation rates and yields. Previous acetylome analysis revealed elevated acetylation levels at lysine residues K91 and K159 of the rhamnose-binding lectin (PmRBL) in gill tissue after implantation. To investigate its immunoregulatory role, a recombinant mutant protein (rPmKQL), mimicking acetylation at these sites, was generated through site-directed mutagenesis. Both wild-type rPmRBL and rPmKQL were injected into nucleus-transplanted <em>P. f. martensii</em>, followed by assessment of immune-related gene expression, immune enzyme activities, and gill cell apoptosis. <em>In vitro,</em> we evaluated the antibacterial and agglutination activities of rPmKQL. The acetylation mimic significantly reduced <em>PmRBL</em> transcript levels and altered the time-dependent expression of NF-<em>κ</em>B pathway genes (IRAK-1, TRAF-3, NF-<em>κ</em>B, and IKK) and inflammatory cytokines (TNF-<em>α</em> and IL-17). Furthermore, rPmKQL significantly enhanced the activities of superoxide dismutase (SOD), catalase (CAT), acid phosphatase (ACP), alkaline phosphatase (AKP), and total antioxidant capacity (T-AOC) at 12 h post-injection, and increased AKP activity at later stages, suggesting improved antioxidant and immune capabilities. Both proteins induced gill cell apoptosis, with no significant difference between the two groups. <em>In vitro</em>, rPmKQL exhibited enhanced antibacterial activity against <em>Staphylococcus aureus</em> and stronger agglutination activity against <em>Pseudomonas aeruginosa</em> and <em>S. aureus</em>, but reduced activity against certain Gram-negative bacteria. Collectively, these results suggest that acetylation at K91/K159 modulates PmRBL function in <em>P. f. martensii</em>, providing mechanistic insight into immune regulation and informing strategies for breeding disease-resistant bivalves.</div></div>","PeriodicalId":12127,"journal":{"name":"Fish & shellfish immunology","volume":"171 ","pages":"Article 111200"},"PeriodicalIF":3.9,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146141619","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":"Bacillus subtilis spores influence the capacity of rainbow trout leukocytes to respond to a posterior viral encounter","authors":"Samuel Vicente-Gil ,&nbsp;Esther Morel ,&nbsp;Bárbara Guedes ,&nbsp;Gabriela Gonçalves ,&nbsp;Rafaela Santos ,&nbsp;Silvia Nogales-Mérida ,&nbsp;Claudia Serra ,&nbsp;Patricia Díaz-Rosales ,&nbsp;Carolina Tafalla","doi":"10.1016/j.fsi.2026.111207","DOIUrl":"10.1016/j.fsi.2026.111207","url":null,"abstract":"<div><div>Although the positive effects of probiotics on the general immune status of aquacultured fish has been widely demonstrated using different probiotic strains and fish species, whether probiotics specifically stimulate antiviral responses has only been scarcely addressed. To provide more insights into this matter, we have investigated the capacity of <em>Bacillus subtilis</em> to modulate the transcription of a range on genes related to antiviral responses in rainbow trout (<em>Oncorhynchus mykiss</em>) through two independent experiments. In the first one, fish were fed a <em>B. subtilis</em>-supplemented diet or a control diet and after 15 or 45 days the levels of transcription of these genes evaluated in kidney and spleen. In the second experiment, fish were fed either of the diets and after 30 days, sacrificed and kidney and spleen leukocytes isolated. These leukocytes were then exposed <em>in vitro</em> to either Poly I:C (an analogue of double stranded RNA) or inactivated viral hemorrhagic septicemia virus (VSHV) (or left untreated). After 24 h of incubation, RNA was extracted from these cultures and the levels of transcription of the antiviral genes analyzed. Our results demonstrate that although the supplemented diet had a faint direct effect on the levels of transcription of these genes in spleen and kidney, it significantly increased the transcriptional response of leukocytes to posterior viral stimuli, pointing to the second method as a more suitable approach to screen for antiviral effects and providing novel insights on the capacity of this probiotic strain to up-regulate antiviral responses.</div></div>","PeriodicalId":12127,"journal":{"name":"Fish & shellfish immunology","volume":"171 ","pages":"Article 111207"},"PeriodicalIF":3.9,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146185958","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":"Integrated immune responses in Manila clam: Antimicrobial activity, immune-related enzymes activity and gene expression profiles following Vibrio anguillarum challenge","authors":"Yongchao Li,&nbsp;Tianshuo Huang,&nbsp;Pengxiang Lin,&nbsp;Jie Yu,&nbsp;Hongtao Nie","doi":"10.1016/j.fsi.2026.111166","DOIUrl":"10.1016/j.fsi.2026.111166","url":null,"abstract":"<div><div>This study examines the innate immune response of the Manila clam (<em>Ruditapes philippinarum</em>) to <em>Vibrio anguillarum</em> infection. Clams were experimentally challenged with <em>V. anguillarum</em>, and samples were collected at different time to assess hemocyte counts, antibacterial and bacteriolytic activity, acid phosphatase (ACP) and lysozyme (LZM) activity, and expression of immune-related genes (<em>CTL-3</em>, <em>Defensin</em>, <em>NFκB1</em>, <em>IκBα</em>, <em>TNF-αL</em>, <em>IL17</em>). Results showed a significant increase in total hemocyte count after <em>V. anguillarum</em> challenge. Antibacterial activity in hemolymph peaked at 6 h post challenge (hpc) with a 2.2-fold increase, while bacteriolytic activity reached 2.4-fold at 24 hpc. ACP activity in hepatopancreas and gills peaked at 12 hpc (1.3- and 1.6-fold increases), and LZM activity peaked at 6 hpc (1.4- and 1.5-fold). Gene expression was dynamically upregulated in a tissue-specific manner, with key genes such as <em>CTL-3</em>, <em>Defensin</em>, and <em>NFκB1</em> showing early peaks in hepatopancreas. The concentration of TNF-α and IL17 also rose significantly after <em>V. anguillarum</em> challenge. The concentration of TNF-α showed a significant difference from the control group at 6–72 hpc (<em>P</em> &lt; 0.05), and the concentration of IL17 showed a significant difference from the control group at 24–72 hpc (<em>P</em> &lt; 0.05). These findings demonstrate that <em>V. anguillarum</em> induces a rapid and integrated immune response in Manila clam, involving both cellular and humoral components, and provide new insights into bivalves innate immunity.</div></div>","PeriodicalId":12127,"journal":{"name":"Fish & shellfish immunology","volume":"171 ","pages":"Article 111166"},"PeriodicalIF":3.9,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146085017","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":"Indole-3-propionic acid enhances intestinal health and protects against Aeromonas hydrophila infection in high-fat-diet fed Nile tilapia (Oreochromis niloticus)","authors":"Fei-Fei Ding ,&nbsp;Shi-Qi Deng ,&nbsp;Yu-Xin Fan ,&nbsp;Shi-Yan Qiao ,&nbsp;Gang Wang","doi":"10.1016/j.fsi.2026.111180","DOIUrl":"10.1016/j.fsi.2026.111180","url":null,"abstract":"<div><div>High fat diet (HFD) is widely utilized in aquaculture to promote growth and feed protein retention, but overconsumption of fat will induce systemic metabolic disorders of fish accompanied by impaired intestinal health and lower pathogen resistance. Indole-3-propionic acid (IPA) has been widely reported to enhance intestinal health in mammals. Our previous study has proven that IPA alleviated lipid metabolism disorder and lipotoxic liver injury in Nile tilapia (<em>Oreochromis niloticus</em>). However, it remains unclear whether IPA can sustain fish intestinal health. In this study, 540 Nile tilapia (2.53 ± 0.02 g) were allotted in 6 groups with 3 tanks each and fed with control diet or high-fat diet supplemented with different levels of IPA (0, 20, 40, 80, 160 mg/kg) respectively. After 8 weeks, it was observed that 80 mg/kg IPA proved the most beneficial for decreasing intestinal myeloperoxidase (MPO) enzyme activity and improving the survival rate of Nile tilapia infected with <em>Aeromonas hydrophila</em>. Dietary IPA restored intestinal barrier integrity impaired by HFD and increased the genes expression of tight junctional proteins (tjps), such as zona occludens 1 (<em>zo-1</em>) and <em>occludin</em>. The results showed that dietary IPA effectively mitigated HFD caused intestinal oxidative stress, manifesting as lower levels of reactive oxygen species (ROS) and malondialdehyde (MDA) and higher activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px). Dietary IPA promoted the gene and protein expression of aryl hydrocarbon receptor (Ahr) in intestine. Further investigation suggested that IPA could activate Ahr and affect nuclear factor-E2-related factor 2 (NRF2) signaling to reduce oxidative stress. Moreover, IPA might suppress enteritis by inhibiting the Ahr-mediated nuclear factor kappa light-chain-enhancer of activated B (NF-κB) signaling pathway. These findings indicated that IPA has the potential to improve intestinal health and pathogen resistance in HFD-fed fish, offering crucial insights for the application of innovative additives in aquatic feeds.</div></div>","PeriodicalId":12127,"journal":{"name":"Fish & shellfish immunology","volume":"171 ","pages":"Article 111180"},"PeriodicalIF":3.9,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146118308","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":"Bivalent inactivated whole cell vaccine confers protection against Aeromonas jandaei and Edwardsiella tarda in oscar fish (Astronotus ocellatus)","authors":"Qurat Ul Ain ,&nbsp;Arun Sudhagar ,&nbsp;Sagar Gorakh Satkar ,&nbsp;Arathi Dharmaratnam ,&nbsp;Gayatree Behera ,&nbsp;Anutosh Paria ,&nbsp;Mattalakkal Unnikrishnan Rekha ,&nbsp;Thipramalai Thangappan Ajith Kumar","doi":"10.1016/j.fsi.2026.111190","DOIUrl":"10.1016/j.fsi.2026.111190","url":null,"abstract":"<div><div>In recent years, multiple pathogenic organisms have been isolated from diseased fish, highlighting the need for combination vaccines to prevent infections caused by various pathogens. This study presents a comparative evaluation of heat- and formalin-inactivated bivalent vaccines targeting <em>Aeromonas jandaei</em> and <em>Edwardsiella tarda</em> tested in Oscar fish (<em>Astronotus ocellatus</em>). Formalin and heat-inactivated vaccines were prepared after optimizing the inactivation conditions. A concentration of 0.3% formalin applied overnight was optimal for formalin inactivation, while heating at 70 °C for 1 h was suitable for heat inactivation. After a combined bacterial challenge 12 weeks from the primary dose, the relative percentage survival (RPS) was 92.6% for the formalin-inactivated vaccine (VFI) and 82.5% for the heat-inactivated vaccine (VHI), indicating strong protective efficacy. Biochemical analysis showed that the vaccinated groups had significantly lower glutamic oxaloacetic transaminase (GOT) and glutamate pyruvic transaminase (GPT) levels post-infection, while oxidative stress assessment revealed enhanced antioxidant defence in the vaccinated fish, with catalase activity peaking on the 2nd dpc in the VFI group. Immune-related gene expression analysis (IgM-H, IL-8, MHC-IIα, and CC-1) revealed significantly higher expression levels in the vaccinated groups than in the control group. Additionally, specific serum antibody against both <em>A. jandaei</em> and <em>E. tarda</em> were significantly elevated in the vaccinated groups compared to those in the controls. The highest anti-<em>A. jandaei</em> antibodies occurred in week 5 after the final booster in both the VFI and VHI groups, whereas anti-<em>E. tarda</em> antibodies peaked in week 4 after the final booster, underscoring the vaccine's robust humoral immune response. Overall, this study demonstrated that both inactivated bivalent vaccines (VFI and VHI) effectively stimulated immune responses in Oscar fish. However, VFI exhibited a slightly superior performance compared to VHI in terms of survival, protective efficacy, and enhanced immune responses against both <em>A. jandaei</em> and <em>E. tarda</em>.</div></div>","PeriodicalId":12127,"journal":{"name":"Fish & shellfish immunology","volume":"171 ","pages":"Article 111190"},"PeriodicalIF":3.9,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146131416","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}