猪链球菌2型假定外膜蛋白Omp40免疫原性的鉴定

Identification of predicted outer membrane protein component's immunogenicity of Streptococcus suis type 2

为了研究猪链球菌2型假定外膜蛋白Omp40的免疫保护性作用,根据已发表的猪链球菌2型猪源98HAH33株的Omp40蛋白的基因序列,选择免疫原性较好的基因序列设计并合成引物,以HA9801株的基因组DNA为模板,采用PCR扩增出Omp40蛋白的部分基因定向克隆至表达载体pET-32a(+)中并转化入BL21(DE3)宿主菌。重组菌经IPTG诱导后的SDS-PAGE图谱显示在52.5 ku处出现融合蛋白的条带。Western-blot结果显示,其与猪源ZY05719株康复血清有良好的免疫反应性。动物试验结果证实,经Omp40蛋白免疫小鼠的血清抗体效价在二免后第7天高达1∶50 800,IL-4和IFN-γ mRNA的表达量在二免后第7天均与对照组相比差异显著(P<0.05),并对猪链球菌2型强致病性株HA9801感染斑马鱼提供22%的免疫保护率。本研究为今后猪链球菌病亚单位疫苗的研究提供了实验依据。

To study the immune protection of putative Omp40 protein of Streptococcus suis type 2（SS2）,primers were designed based on the immunogenic region.The genome of SS2 HA9801 strain was used as a template and the amplified fragment was inserted into the expression plasmid pET-32a（＋）.After inducing with IPTG,a52.5 ku band was identified by SDS-PAGE.Western-blot results showed that this protein had great immunoreactivity to convalescent serum of a pig recovered from SS2 ZY05719 infection.The antibody titer of mouse immunized with Omp40 might reach to 1 ∶ 50 800 on day 7 after the second immunization.Animal experiments indicated Omp40 might influence the mRNA transcription level of IL-4 and IFN-γ significantly （P0.05） on day 7 after the second immunization,which provided the immune protection rate of 22% to zebrafish against virulent SS2 infection.This study contributes to the development of subunit vaccines against SS2 infection.