Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Northeast Agricultural University, Harbin, PR China.
Comp Immunol Microbiol Infect Dis. 2011 Jan;34(1):73-81. doi: 10.1016/j.cimid.2010.02.004. Epub 2010 Mar 11.
The major structural protein VP2 of porcine parvovirus (PPV) was used as the model parvovirus antigen, which has been expressed in Lactobacillus casei fusing with Escherichia coli heat-labile enterotoxin B subunit (LTB) as mucosal adjuvant. The VP2-LTB DNA fragment was cloned into vector pPG611 or pPG612 to generated inducible surface-displayed and secretion expression systems based on xylose promoter, designated as rLc:pPG611-VP2-LTB (recombinant L. casei) and rLc:pPG612-VP2-LTB, respectively. Expression of the fusion protein was verified by SDS-PAGE, Western blot immunofluorescence and electron microscopy. It was observed that the level of IgG or sIgA from mice orally immunized with VP2-LTB was higher than that from mice received VP2 and negative control, which demonstrated significantly statistically different. Especially, the titer of IgG or sIgA in mice immunized with rLc:pPG612-VP2-LTB is the highest in this study. In summary, LTB as mucosal adjuvant was able to effectively facilitate induction of mucosal and systemic immunity by L. casei-expressing VP2 fusion protein.
猪细小病毒(PPV)的主要结构蛋白 VP2 被用作模式细小病毒抗原,与大肠杆菌不耐热肠毒素 B 亚单位(LTB)融合在乳杆菌中表达作为黏膜佐剂。VP2-LTB DNA 片段被克隆到载体 pPG611 或 pPG612 中,基于木糖启动子,分别生成诱导型表面展示和分泌表达系统,命名为 rLc:pPG611-VP2-LTB(重组乳杆菌)和 rLc:pPG612-VP2-LTB。融合蛋白的表达通过 SDS-PAGE、Western blot 免疫荧光和电子显微镜进行验证。结果观察到,用 VP2-LTB 口服免疫的小鼠的 IgG 或 sIgA 水平高于接受 VP2 和阴性对照的小鼠,这表明存在显著的统计学差异。特别是,在本研究中,用 rLc:pPG612-VP2-LTB 免疫的小鼠的 IgG 或 sIgA 的滴度最高。总之,LTB 作为黏膜佐剂能够有效地促进表达 VP2 融合蛋白的乳杆菌诱导黏膜和系统免疫。