Department of Veterinary Medicine, College of Veterinary Medicine, National Pingtung University of Science and Technology, Neipu, Pingtung, Taiwan.
International Degree Program of Ornamental Fish Technology and Aquatic Animal Health, International College, National Pingtung University of Science and Technology, Neipu, Pingtung, Taiwan.
J Fish Dis. 2024 Nov;47(11):e14009. doi: 10.1111/jfd.14009. Epub 2024 Aug 29.
Four-finger threadfin, Eleutheronema tetradactylum farming in southern Taiwan has been facing disease problems caused by Streptococcus iniae since 2018. The development of a vaccine against infectious S. iniae in the cultured threadfin industry is necessary. Thus, this study aimed to examine the efficacy of threadfin immunized formalin-killed cells (FKC) from S. iniae GSI-111 for 42 days post-vaccination (dpv) using two doses of FKC alone (a booster at 14 dpv) as group A, and FKC mixed with ISA763A adjuvant using a single dose as group B or double doses as group C. Immunoglobulin (Ig)-M was purified from threadfin, and rabbit anti-threadfin IgM polyclonal antibodies were used to detect antibody level in immunized fish; the vaccinated group A displayed higher levels at 3 dpv and all vaccinated treatments demonstrated high antibody levels between 14 and 42 dpv. All vaccine groups showed significantly higher values of lysozyme activity at 42 dpv compared with the control group; the vaccinated A group peaked at 14 dpv. The expression profiles of pro-inflammatory and immune-related genes, TNF-α, IL-12A, and C2 were upregulated at 3 dpv, while CD8A and chemokine receptor CXCR4 were upregulated at 42 dpv. Finally, the threadfins were challenged with S. iniae at 42 dpv. The average relative percent survival was 96% for vaccination A and B treatments, and 100% for vaccination C treatment. In summary, this study demonstrated that FKC vaccines whether formulated with an adjuvant could stimulate immune response and effective protect threadfins against S. iniae infection.
台湾南部的四指马鲅（Eleutheronema tetradactylum）养殖自 2018 年以来一直面临链球菌（Streptococcus iniae）引起的疾病问题。因此，开发一种针对养殖马鲅传染性链球菌的疫苗是必要的。本研究旨在检测两种剂量的马鲅福尔马林灭活细胞（FKC）单独（在 14 天加强）作为 A 组、FKC 与 ISA763A 佐剂混合使用单次剂量作为 B 组或两次剂量作为 C 组对 42 天（dpv）后的免疫效果。从马鲅中纯化免疫球蛋白（Ig）-M，并用兔抗马鲅 IgM 多克隆抗体检测免疫鱼的抗体水平；免疫 A 组在 3 dpv 时显示出更高的水平，所有免疫组在 14 至 42 dpv 期间均显示出高抗体水平。所有疫苗组在 42 dpv 时溶菌酶活性均显著高于对照组；免疫 A 组在 14 dpv 时达到峰值。促炎和免疫相关基因 TNF-α、IL-12A 和 C2 的表达谱在 3 dpv 时上调，而 CD8A 和趋化因子受体 CXCR4 在 42 dpv 时上调。最后，在 42 dpv 时用 S. iniae 对马鲅进行攻毒。A 组和 B 组疫苗接种的平均相对存活率为 96%，C 组疫苗接种的平均相对存活率为 100%。综上所述，本研究表明，无论是否添加佐剂，FKC 疫苗都能刺激免疫反应，有效保护马鲅免受 S. iniae 感染。
