The largemouth bass virus (LMBV) is a commonly encountered pathogen in aquaculture and presents significant challenges to development of the largemouth bass industry due to the lack of effective treatment methods. Here, the inhibitory potential and underlying mechanisms of adamantoyl chloride (AdCl) against LMBV were assessed both in vitro and in vivo . The results showed that AdCl (IC 50 = 72.35 μM) significantly inhibited replication of LMBV in epithelioma papulosum cyprini (EPC) cells. The results of the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide and cytopathic effect (CPE) assays confirmed that AdCl inhibited replication of LMBV in EPC cells and significantly reduced the CPE effect, respectively. As a potential mechanism, AdCl inhibited apoptosis as determined by fluorescence and transmission electron microscopy. The results of flow cytometry showed that the apoptosis rate was decreased by 69 % in the AdCl-treated group as compared to the LMBV-infected group. Additionally, AdCl inhibited viral release. In vivo , the survival rate was 16.2 % higher in the AdCl-treated group as compared to the LMBV-infected group (26.9 % vs. 10.7 %, respectively). Additionally, the results of quantitative reverse transcription polymerase chain reaction (RT-qPCR) showed that AdCl significantly reduced the viral load of the fish liver, spleen, and kidneys at 3, 6, and 9 days postinfection. In addition, RT-qPCR analysis found that AdCl upregulated expression of immune-related genes to suppress replication of LMBV. Collectively, these results confirmed the anti-LMBV activities of AdCl for use in the aquaculture industry.
In situ mineralization successfully fabricated a nano-selenium-functionalized LMBV inactivated vaccine (SeNPs/LMBV). • The SeNPs/LMBV vaccine exhibited SOD- and CAT-like antioxidant activities, modulating the immune microenvironment. • The SeNPs/LMBV vaccine significantly enhanced neutralizing antibody titers and upregulated immune-related genes. • The SeNPs/LMBV vaccine provided robust protection against lethal LMBV challenge with a 77.5% relative percent survival. Largemouth bass ranavirus (LMBV) is a major viral pathogen threatening the sustainable development of the largemouth bass ( Micropterus salmoides ) aquaculture industry. However, conventional inactivated vaccines generally exhibit limited immunogenicity and insufficient immune protection. Herein, a nano-selenium-functionalized inactivated vaccine (SeNPs/LMBV inactivated vaccine) was successfully constructed through an in situ mineralization strategy, in which selenium ions were initially assembled onto the surface of inactivated LMBV particles through electrostatic interactions and subsequently reduced into elemental selenium nanoparticles. Transmission electron microscopy revealed that selenium nanoparticles with sizes of approximately 20-50 nm were uniformly assembled on the surface of inactivated LMBV particles, forming a stable nano-bio interface structure. The obtained SeNPs/LMBV inactivated vaccine exhibited significant superoxide dismutase (SOD)-like and catalase (CAT)-like antioxidant activities, indicating potent antioxidant capacity. Biosafety evaluations demonstrated that the SeNPs/LMBV inactivated vaccine caused no obvious cytotoxicity or histopathological damage at the experimental dosage, suggesting favorable biocompatibility. Moreover, immunization with the SeNPs/LMBV inactivated vaccine significantly enhanced serum neutralizing antibody titers and upregulated the expression of immune-related genes, including TNF-α, IL-1β, IFN-γ, and IgM, compared with the conventional inactivated vaccine. Following lethal LMBV challenge, the relative percent survival (RPS) of the SeNPs/LMBV-immunized group reached 77.5%. Collectively, these findings demonstrate that in situ mineralization of nano-selenium can effectively enhance the immune protective efficacy of inactivated LMBV vaccines, providing a promising strategy for the prevention and control of LMBV infection and highlighting the potential application of nano-selenium adjuvants in aquatic viral vaccines. Download: Download high-res image (156KB) Download: Download full-size image
危险品化学品经营许可证（带存储）