罗非鱼链球菌病弱毒活疫苗和灭活疫苗口服接种抗原示踪及保护率比较

Efficacy of Tilapia Streptococcal Disease Live Attenuated Vaccine and Inactivated Vaccine Antigen DNA Tracer and Protection Rate Comparison Delivered by Oral Administration

为比较罗非鱼链球菌病弱毒活疫苗和灭活疫苗的口服免疫效果,对两种疫苗口服接种罗非鱼后0 h、6 h、12 h、1 d、3 d、5 d、7 d、9 d、11 d、13 d和15 d的脑、肝、脾和后肾组织进行细菌分离检测,采用Taqman实时荧光定量PCR技术对肝、脾、中肠和头肾组织中无乳链球菌DNA进行检测定量示踪抗原,并对两种疫苗口服接种保护率进行比较。罗非鱼口服接种弱毒疫苗6 h、12 h、1 d的脑、肝、脾、后肾均可分离出无乳链球菌,3 d之后脑和11 d之后肝细菌分离为阴性,15 d的脾仍为阳性,后肾3 d之后细菌分离为阴性,灭活疫苗组和空白组均为阴性;实时荧光定量PCR检测结果显示两种疫苗口服灌胃后6 h即可在罗非鱼组织中检测到无乳链球菌,且弱毒组检测值均高于灭活组,弱毒组7 d内肝、脾、中肠、头肾组织中无乳链球菌数量检测值均高于104cells,灭活组5d后各组织检测值均下降为0。罗非鱼弱毒活疫苗和灭活疫苗口服灌胃后15 d腹腔注射攻毒,弱毒组和灭活组相对免疫保护率分别为70.69%和29.31%。研究结果为进一步研究罗非鱼链球菌病口服疫苗及其免疫机理奠定基础。

To compare the oral immunization effect of attenuated live vaccine and inactivated vaccine of tilapia streptococcal disease,bacterial isolation and detection of brain,liver,spleen and kidney of tilapia is performed at 0 h,6 h,12 h、1 d,3 d,5 d,7 d,9 d,11 d,13 d and15 d after oral vaccination with two vaccines separately. Taqman real-time PCR was used for DNA quantitative tracer of Streptococcus agalactiae in the liver,spleen,midgut and head kidney tissue,and the protection rate of two vaccines by oral vaccination was compared. Streptococcus agalactiae could be isolated in the brain,liver,spleen and kidney at 6 h,12 h,1 d after oral vaccination of attenuated live vaccine.Bacterial isolation was negative after 3 d and 11 d in brain and liver separately,positive at 15 d in spleen,negative after 3 d in kidney. Inactivated vaccine group and the control group were negative. Real-time quantitative PCR showed that Streptococcus agalactiae DNA could be detected in tissues of tilapia at 6 h after oral vaccination,and attenuated group detected values were higher than inactivated group. The attenuated group detected values were higher than 104 cells in liver,spleen,midgut and head kidney in 7 d. The inactivated group detected values were 0 after 5 d. The relative percent survival of attenuated group and inactivated group was 70. 69 % and 29. 31 % at 15 d after oral vaccination separately. The results lay the foundation for the further study of tilapia streptococcal disease oral vaccine and immune mechanism.