肠型点状产气单胞菌口服疫苗对草鱼的免疫保护效应研究

Immunogenecity and Protective Effects of an Oral Vaccine Microparticle Against Aeromonas punctata F.intestinalis in Grass Carp(Ctenopharyngodon idella)

采用生物可降解材料聚丙烯酸树脂制备含肠型点状产气单胞菌的微粒疫苗,口服免疫草鱼,测定实验鱼血清抗体及其对活菌攻击的保护率.实验结果显示,用肠型点状产气单胞菌微粒疫苗进行口服免疫或用全菌疫苗、佐剂疫苗进行注射免疫均可诱导草鱼的血清抗体应答,对肠型点状产气单胞菌攻击的草鱼具有一定的保护作用,保护率分别为52.4%、66.7%及71.4%,对照组仅有16.0%的存活率.可见,口服微粒疫苗对草鱼有显著免疫保护效应,可作为预防肠型点状产气单胞菌感染的疫苗.

Aeromonas punctata f. intestinalis is a common Gram negative bacterial pathogen involved in diseases of grass carp. The killed whole cells of the bacteria were encapsulated in the poly（acrylic acid） microparticles. The efficacy of the resulting vaccine microparticles was evaluated by the serum antibody responses and the protective effects in orally immunized grass carp. Like injection of the whole-cell vaccine or adjuvant vaccine （the whole-cell vaccine containing adjuvant）, oral administration of the vaccine microparticles triggered obvious serum antibody responses. The protective effects of the vaccines were examined by survival rates. After challenge with 50 LD50 of Aeromonas punctata f. intestinalis, the survival rates of fish receiving the oral vaccine microparticles, the injected whole-cell vaccine or the injected adjuvant vaccine were 52.4%, 66.7% or 71.4%, respectively, whereas only 16.0% of the fish receiving free microparticles survived. It is suggested that the oral vaccine microparticles had significant protective effects on grass carp and might be used as an effective fish vaccine against Aeromonas punctata f. intestinalis infection.