A Combination Vaccine against Encephalomyocarditis Virus and Porcine Circovirus Type 2 Induces Protective Immune Response in Pigs

Encephalomyocarditis virus (EMCV) and porcine circovirus type 2 (PCV2) are common causative agents with high infection rate in pig farms, thus a combined vaccine against both EMCV and PCV2 is highly desirable. In the present study, we developed an oil-adjuvant combination vaccine candidate comprising of inactivated EMCV and PCV2, and evaluated the safety and immunogenicity in mice and swine. The combination vaccine was found to elicit serum antibodies and had strong neutralization activity, more importantly, passive immunization with the combined vaccine protected swine against either EMCV or PCV2 lethal infections, whereas the monovalent vaccine only prevent the one of two virus challenge. Our results demonstrated the combined vaccine was safe and induced protective immune response in mice and swine as evident from sero-conservation as well as challenge studies in swine, indicating that component vaccines did not interfere with the immunogenicity of each other.

鸭源鸡杆菌ompW、gtxA双基因缺失株的构建及其相关特性分析

鸭源鸡杆菌(Gallibacterium anatis,G.anatis)是家禽中常见的条件性致病菌,主要引起蛋鸡生殖道疾病,造成产蛋量下降。【目的】为探究RTX样毒素GtxA及外膜蛋白(OmpW)对鸭源鸡杆菌生物学特性和致病力的影响。【方法】本研究采用自然转化法对突变株RZ△ompW进一步缺失gtxA构建突变株RZ△ompW△gtxA,通过分析其生长特性、黏附能力、引起细胞凋亡程度及对小鼠致病性等,探究其与生物学特性及致病性可能的关系。【结果】结果显示,RZ△ompW△gtxA能稳定遗传gtxA的缺失;单双基因突变株溶血活性均消失、与RZ株相比菌落形态及生长速率并未出现显著改变;相比RZ、RZ△ompW和RZ△gtxA,双基因缺失株RZ△ompW△gtxA在不同时段对鸡原代输卵管上皮细胞的黏附能力显著降低(P<0.05),诱导鸡输卵管上皮原代细胞发生凋亡的能力明显减弱,对小鼠的致病力显著降低。【结论】GtxA毒素和外膜蛋白OmpW在鸭源鸡杆菌毒力、黏附宿主细胞及诱导其细胞凋亡中起重要作用,且可能存在明显的协同关系。本研究为鸭源鸡杆菌感染机制的阐明奠定基础。