Yamasaki Masatoshi, Araki Kyosuke, Maruyoshi Kota, Matsumoto Megumi, Nakayasu Chihaya, Moritomo Tadaaki, Nakanishi Teruyuki, Yamamoto Atsushi
The United Graduate School of Agricultural Sciences, Kagoshima University, 1-21-24 Korimoto, Kagoshima 890-8580, Japan.
Faculty of Fisheries, Kagoshima University, 4-50-20 Shimoarata, Kagoshima 890-0056, Japan.
Fish Shellfish Immunol. 2015 Aug;45(2):437-42. doi: 10.1016/j.fsi.2015.04.038. Epub 2015 May 7.
Edwardsiella tarda is an intracellular pathogen that causes edwardsiellosis in fish. Although vaccine trials with formalin-killed cells (FKC) have been reported, the vaccinations failed in protect against E. tarda infection. On the other hand, a live attenuated vaccine strategy is effective against edwardsiellosis; however, the mechanism underlying its effectiveness in fish is unclear. In the present study, we compared the adaptive immune responses in fish vaccinated with FKCs and live attenuated vaccines to elucidate the induction of adaptive immune responses following vaccination. After challenge with E. tarda, live cell (LC)-vaccinated fish showed high survival rates, high IFN-g and T-bet gene expression levels, and increased cytotoxic T lymphocytes (CTLs). In contrast, all FKC-vaccinated fish died following E. tarda infection. In addition, FKC vaccination induced high IL-4/13A and IL-10 expression levels and increased antibody titers, whereas Th1-like responses were suppressed. These results indicate that LC vaccination contributes to protection against E. tarda infection by inducing cell-mediated immunity (CMI). Thus our study findings could contribute to the development a vaccine that induces CMI against edwardsiellosis.
迟缓爱德华氏菌是一种细胞内病原体，可导致鱼类患爱德华氏菌病。尽管已有使用福尔马林灭活细胞（FKC）进行疫苗试验的报道，但这些疫苗接种未能预防迟缓爱德华氏菌感染。另一方面，减毒活疫苗策略对爱德华氏菌病有效；然而，其在鱼类中发挥作用的机制尚不清楚。在本研究中，我们比较了接种FKC和减毒活疫苗的鱼类的适应性免疫反应，以阐明接种疫苗后适应性免疫反应的诱导情况。在用迟缓爱德华氏菌攻击后，接种活细胞（LC）的鱼类显示出高存活率、高干扰素-γ和T-bet基因表达水平，以及细胞毒性T淋巴细胞（CTL）增加。相比之下，所有接种FKC的鱼类在迟缓爱德华氏菌感染后均死亡。此外，FKC疫苗接种诱导了高白细胞介素-4/13A和白细胞介素-10表达水平以及抗体滴度增加，而Th1样反应受到抑制。这些结果表明，LC疫苗接种通过诱导细胞介导免疫（CMI）有助于预防迟缓爱德华氏菌感染。因此，我们的研究结果可能有助于开发一种诱导针对爱德华氏菌病的CMI的疫苗。
