马链球菌兽疫亚种的保护性抗原SzP蛋白的鉴定与评价

Identification and evaluation of a surface protective antigen,SzP of Streptococcus equi ssp. zooepidemicus

马链球菌兽疫亚种是引起猪链球菌病的主要病原之一。该菌的致病机理尚不清楚,且缺乏合适的疫苗,使猪链球菌病很难得到有效的控制。本实验通过构建SzP重组表达载体,纯化重组蛋白,对其的免疫效力进行了评价。结果表明该蛋白可以诱导高滴度的血清IgG抗体,并且可提供一定的免疫保护效力。进一步研究表明该蛋白是一个重要的体内诱导抗原,可诱导高水平的Th1和Th2型免疫应答。揭示了SzP蛋白在致病过程中起到重要作用,为新型疫苗的研制及致病机制的研究奠定了基础。

Streptococcus equi ssp. zooepidemicus （SEZ） is an important pathogen associated with opportunistic infections of pigs in China. The absence of suitable vaccines or the knowledge of virulence markers could block the step for controlling SEZ infection. M-like protein （SzP） has been identified as an immunogenic protein in the previous study but its protective efficacy was not clear. In the present study, the purified recombinant SzP could elicit a significant humoral antibody response and could confer significant protection against challenge with lethal dose of SEZ in mice model. In addition, the SzP was an in vivo-induced antigen confirmed by the real-time PCR and could induce significant Thl-/Th2-immune responses. Our findings suggested that SzP played an important role in the pathogenesis of SEZ and could be a target for the development of an effective vaccine against SEZ infection.