Studies on the vaccine against infection of Pathogenic bacterium Edwardsiella tarda

首先以具有代表性的EF-1菌株为研究对象，研究了在不同血清型迟发爱德华氏菌中常见的37 kDa外膜蛋白（Omp37Et）的培养条件。用2种不同血清型菌株ef - 1和v - 1制备的纯化的Omp37Et免疫鳗鱼，可保护ef - 1菌株活细胞的感染。用ef - 1株制备的Omp37Et免疫日本牙鲆，可保护ef - 1和v - 1株活细胞的感染。结果表明，Omp37Et是不同血清型迟发性大肠杆菌共同的保护抗原。免疫后的鱼抗体滴度和吞噬细胞活性均有所提高。对Omp37Et进行氨基酸序列分析，鉴定出n端有14个氨基酸。在不同给药方式（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。免疫反应在血清抗体滴度和吞噬细胞活性方面表现出与保护相同的顺序。体外低pH和鱼消化酶处理可降低福尔马林杀伤细胞疫苗的抗原性。事实表明，用抗低pH或-酶包埋或包膜疫苗抗原，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.