Agriculture Ministry Key Laboratory of Healthy Freshwater Aquaculture, Key Laboratory of Fish Health and Nutrition of Zhejiang Province, Zhejiang Institute of Freshwater Fisheries, Huzhou, China.
Development Center of Huzhou Agricultural Science and Technology, Huzhou, China.
Front Immunol. 2022 Mar 4;13:852300. doi: 10.3389/fimmu.2022.852300. eCollection 2022.
Largemouth bass iridovirus (LMBV) can cause high mortality and lead to heavy economic loss in the cultivation of largemouth bass, but there was no effective treatment. Here, the present study constructed a recombinant expressing LMBV major capsid protein (). The recombinant GS115-pW317- was then used to immunize largemouth bass oral administration, and mucosal immune response mediated by immunoglobulins (Igs) was measured after oral immunization. Serum antibody levels were measured by ELISA, neutralizing antibody titers were determined by serum neutralization test (SNT), antigen presentation-related gene expressions were detected by RT-PCR, and the histopathological characteristics of immunized fish were assessed after challenging with 0.1 ml 10 TCID/ml LMBV. The relative percentage survival (RPS) was also determined. Our results showed that the serum antibody titers of immunized fish were significantly higher than that of control groups (P < 0.05). IgT and IgM expressions in gut were increased significantly after vaccination with GS115-pW317-; however, much stronger response in gut was observed as compared with gill. The expression levels of major histocompatibility complex () II, 8, and T-cell receptor () were significantly elevated in GS115-pW317- group (P < 0.05), while 4 and I transcription levels remained unchanged after oral immunization ( > 0.05). The RPS of fish orally immunized with 1.0 × 10 CFU/g GS115-pW317- was reached up to 41.6% after challenge with 0.1 ml 10 TCID/ml LMBV. Moreover, orally immunizing with GS115-pW317- can relieve the pathological damage caused by LMBV. Therefore, GS115-pW317- showed a promising potential against LMBV.
大口黑鲈虹彩病毒（LMBV）可导致大口黑鲈养殖过程中高死亡率，造成严重的经济损失，但目前尚无有效的治疗方法。本研究构建了表达 LMBV 主要衣壳蛋白（）的重组。重组 GS115-pW317- 随后用于经口免疫大口黑鲈，经口免疫后测量免疫球蛋白（Igs）介导的黏膜免疫反应。通过酶联免疫吸附试验（ELISA）测量血清抗体水平，通过血清中和试验（SNT）测定中和抗体滴度，通过 RT-PCR 检测抗原呈递相关基因的表达，并在 0.1 ml 10 TCID/ml LMBV 攻毒后评估免疫鱼的组织病理学特征。还确定了相对存活率（RPS）。结果表明，免疫鱼的血清抗体滴度明显高于对照组（P < 0.05）。接种 GS115-pW317- 后，肠道中的 IgT 和 IgM 表达明显增加；然而，与鳃相比，肠道中的反应更强。GS115-pW317- 组主要组织相容性复合体（MHC）II、8 和 T 细胞受体（TCR）的表达水平显著升高（P < 0.05），而经口免疫后 4 和 I 的转录水平保持不变（> 0.05）。经 1.0×10 CFU/g GS115-pW317- 经口免疫的鱼在 0.1 ml 10 TCID/ml LMBV 攻毒后的 RPS 达到 41.6%。此外，经口免疫 GS115-pW317- 可减轻 LMBV 引起的病理损伤。因此，GS115-pW317- 显示出对 LMBV 的潜在应用前景。
