猪链球菌2型一种新的免疫原性蛋白的鉴定及特性分析

Identification and characterization of a novel antigenic protein of Streptococcus suis type 2

摘要:

利用免疫蛋白组学方法,鉴定出链球菌2型(Streptococcus suis type2,SS2)江苏分离株HA9801具有免疫反应性的蛋白HM3。应用同源性比对、信号肽预测、跨膜区预测及亚定位预测等生物信息学方法对该蛋白进行分析,结果显示:同源性最高的蛋白为屎肠球菌胞外溶解物结合蛋白(41%);蛋白序列中含有信号肽结构;7-24位氨基酸为该蛋白的跨膜区;预测蛋白定位为除胞质外的未定位置。PCR扩增出该蛋白的一段基因定向克隆到表达载体pET-32a(+)中并转化入BL21(DE3)宿主菌。重组菌经IPTG诱导后的SDS-PAGE图谱在46kDa处出现融合蛋白的条带。Westernblot表明,此融合蛋白可被SPF微型猪抗SS2血清所识别,提示该蛋白可作为该菌的亚单位疫苗的候选物。

Abstract:

An immunogenic protein, named HM3, of Streptococcus suis type 2 HA9801 was identified by using immunoproteomic assay. Some characters of this protein were analyzed by several online bioinformatical tools, including BLAST, SinglP, HMMTOP and PSORTb. The most homologous sequence of HM3 was extracellular solute-binding protein (gi|69246104) of Enterococcus faecium. The predictions results showed that HM3 contained Signal peptide and one transmembrane region, and Non-Cytoplasmic Localization were also predicted. Partial gene of this protein were amplified from the genome of HA9801 by PCR and inserted into expression plasmid pET-32a (+) after double digested by BamH I and Sal I, then transformed into BL21 (DE3) where they were induced to express by IPTG. After induced, there was specific proteins band of approximately 45kDa on the SDS-PAGE gel. Western-blotting showed that recombinant protein could react with immune serum of HA9801 of SPF (Specefic pathogen Free)mini-swine. This protein could be taken as a vaccine candidate of SS2.