Studies on the vaccine against infection of Pathogenic bacterium Edwardsiella tarda

首先，使用代表性菌株EF-1研究了用于产生抗原的培养条件，所述抗原是通常分布在不同血清型的迟缓爱德华氏菌菌株中的37 kDa外膜蛋白（Omp 37 Et）。用从两种不同血清型菌株EF-1和V-1制备的纯化Omp 37 Et免疫鳗鱼保护EF-1菌株活细胞的感染。用EF-1株制备的Omp 37 Et免疫日本比目鱼，保护EF-1和V-1株活细胞的感染。结果表明，Omp 37 Et是不同血清型迟缓艾美耳球虫的共同保护性抗原。此外，免疫鱼的抗体滴度和吞噬细胞活性增加。氨基酸序列分析表明Omp 37 Et的N端有14个氨基酸残基。在对迟缓艾美耳球虫灭活细胞疫苗不同给药方法（腹腔注射、浸泡和口服）的比较中，注射的保护效果最好，其次是口服和浸泡。血清抗体效价和吞噬细胞活性的免疫应答与保护性免疫应答的顺序相同。甲醛灭活细胞疫苗经低pH和鱼消化酶处理后，其抗原性降低。这一事实表明，用抗低pH或低pH酶对疫苗抗原进行包裹或包被，以保护抗原免受这些因素的影响。

Culture conditions for the production of the antigen, a 37 kDa outer membrane protein (Omp37Et), commonly distributed among Edwardsiella tarda strains of different serotypes was investigated using representative strain EF-1, first. Immunization of eel with purified Omp37Et prepared from 2 different serotype strains EF-l and V-l protected infection with live cells of EF-l strain. Immunization of Japanese flounder with Omp37Et prepared from EF-l strain protected infection with live cells of EF-l and V-l strains. The results indicate that the Omp37Et is the common protective antigen of E.tarda against different serotypes of E.tarda. Moreover, the immunized fish showed increase in the antibody titer and phagocyte activity. Amino acid sequeuce analysis of the Omp37Et identified 14 amino acid of N-terminal side. In the comparison of different administration methods, intraperitoneal injection, immersion and oral administration, of the formalin-killed cells vaccine of E.tarda, highest protection was resulted by injection then followed with oral administration and immersion. Immune response in the serum antibody titer and phagocyte activity showed same order as in the protection. Antigenicity of the formalin-killed cell vaccine was lowered by in vitro treatment with low pH and digestive enzymes of fish. The fact indicates that encapsulatio or coating of the vaccine antigen with anti-low pH or -enzymes to protect the antigen from the effect of those factors.