Department of Preventive Veterinary, College of Veterinary, Northeast Agricultural University, 59 Mucai Street, Harbin, PR China.
BMC Microbiol. 2009 Dec 4;9:249. doi: 10.1186/1471-2180-9-249.
Porcine rotavirus infection is a significant cause of morbidity and mortality in the swine industry necessitating the development of effective vaccines for the prevention of infection. Immune responses associated with protection are primarily mucosal in nature and induction of mucosal immunity is important for preventing porcine rotavirus infection.
Lactobacillus casei expressing the major protective antigen VP4 of porcine rotavirus (pPG612.1-VP4) or VP4-LTB (heat-labile toxin B subunit from Echerichia coli) (pPG612.1-VP4-LTB) fusion protein was used to immunize mice orally. The expression of recombinant pPG612.1-VP4 and pPG612.1-VP4-LTB was confirmed by SDS-PAGE and Western blot analysis and surface-displayed expression on L. casei was verified by immunofluorescence. Mice orally immunized with recombinant protein-expressing L. casei produced high levels of serum immunoglobulin G (IgG) and mucosal IgA. The IgA titers from mice immunized with pPG612.1-VP4-LTB were higher than titters from pPG612.1-VP4-immunized mice. The induced antibodies demonstrated neutralizing effects on RV infection.
These results demonstrated that VP4 administered in the context of an L. casei expression system is an effective method for stimulating mucosal immunity and that LTB served to further stimulate mucosal immunity suggesting that this strategy can be adapted for use in pigs.
猪轮状病毒感染是猪养殖业中发病率和死亡率的重要原因，因此需要开发有效的疫苗来预防感染。与保护相关的免疫反应主要是黏膜性的，诱导黏膜免疫对于预防猪轮状病毒感染很重要。
鼠李糖乳杆菌表达猪轮状病毒的主要保护性抗原 VP4（pPG612.1-VP4）或 VP4-LTB（来自大肠杆菌的不耐热毒素 B 亚单位）（pPG612.1-VP4-LTB）融合蛋白，通过口服免疫小鼠。重组 pPG612.1-VP4 和 pPG612.1-VP4-LTB 的表达通过 SDS-PAGE 和 Western blot 分析进行确认，鼠李糖乳杆菌表面展示的表达通过免疫荧光进行验证。用表达重组蛋白的鼠李糖乳杆菌口服免疫的小鼠产生高水平的血清免疫球蛋白 G（IgG）和黏膜 IgA。用 pPG612.1-VP4-LTB 免疫的小鼠的 IgA 滴度高于用 pPG612.1-VP4 免疫的小鼠的滴度。诱导的抗体对 RV 感染具有中和作用。
这些结果表明，在鼠李糖乳杆菌表达系统中给予 VP4 是刺激黏膜免疫的有效方法，而 LTB 进一步刺激了黏膜免疫，表明该策略可适应于猪。
