Li Zhiyong, Yi Yongzhu, Yin Xiangping, Zhang Zhifang, Liu Jixing
Key Laboratory of Animal Virology of Ministry of Agriculture, Lanzhou Veterinary Research Institute, Chinese Academy of Agriculture Sciences, Lanzhou, Gansu, China.
PLoS One. 2008 May 28;3(5):e2273. doi: 10.1371/journal.pone.0002273.
Foot-and-mouth disease (FMD) is a highly contagious disease of livestock that causes severe economic loss in susceptible cloven-hoofed animals. Although the traditional inactivated vaccine has been proved effective, it may lead to a new outbreak of FMD because of either incomplete inactivation of FMDV or the escape of live virus from vaccine production workshop. Thus, it is urgent to develop a novel FMDV vaccine that is safer, more effective and more economical than traditional vaccines.
A recombinant silkworm baculovirus Bm-P12A3C which contained the intact P1-2A and 3C protease coding regions of FMDV Asia 1/HNK/CHA/05 was developed. Indirect immunofluorescence test and sandwich-ELISA were used to verify that Bm-P12A3C could express the target cassette. Expression products from silkworm were diluted to 30 folds and used as antigen to immunize cattle. Specific antibody was induced in all vaccinated animals. After challenge with virulent homologous virus, four of the five animals were completely protected, and clinical symptoms were alleviated and delayed in the remaining one. Furthermore, a PD(50) (50% bovine protective dose) test was performed to assess the bovine potency of the subunit vaccine. The result showed the subunit vaccine could achieve 6.34 PD(50) per dose.
The results suggest that this strategy might be used to develop the new subunit FMDV vaccine.
口蹄疫（FMD）是一种家畜高度传染性疾病，会给易感偶蹄动物造成严重经济损失。尽管传统灭活疫苗已被证明有效，但由于口蹄疫病毒（FMDV）灭活不完全或活病毒从疫苗生产车间逃逸，可能导致口蹄疫新的爆发。因此，迫切需要开发一种比传统疫苗更安全、更有效、更经济的新型FMDV疫苗。
构建了一种重组家蚕杆状病毒Bm-P12A3C，其包含FMDV Asia 1/HNK/CHA/05完整的P1-2A和3C蛋白酶编码区。采用间接免疫荧光试验和夹心ELISA验证Bm-P12A3C能否表达目标盒。将家蚕表达产物稀释30倍后用作抗原免疫牛。所有接种动物均诱导出特异性抗体。用强毒同源病毒攻击后，五只动物中有四只完全得到保护，其余一只动物的临床症状得到缓解且出现延迟。此外，进行了PD(50)（50%牛保护剂量）试验以评估亚单位疫苗的牛效力。结果表明，该亚单位疫苗每剂量可达到6.34个PD(50)。
结果表明该策略可用于开发新型FMDV亚单位疫苗。
