摘要
目的研究空肠弯曲菌多价DNA疫苗的免疫保护效应。方法以壳聚糖包裹含空肠弯曲菌主要结构蛋白cadF和peb1A编码基因的重组质粒pcDNA3.1(+)-cadF和pcDNA3.1(+)-peblA,制备空肠弯曲菌多价DNA疫苗。以含60μgDNA的不同效价的DNA疫苗于实验开始的0、7、14和21d滴鼻免疫BALB/c小鼠4次,检测其诱导特异性免疫应答的效应。末次免疫后8w,分别采用空肠弯曲菌HS∶19或HS∶2单次和HS∶19重复攻击的方式进行灌胃攻击。攻击后,对该疫苗的免疫保护作用进行评价,包括该疫苗阻止空肠弯曲菌肠道定植和肠外扩散的效力,以及防御空肠弯曲菌感染导致周围神经、小肠和肝脏组织损伤的效应。结果空肠弯曲菌多价DNA疫苗滴鼻免疫小鼠后,不仅诱导了高水平的血清IFN-γ、IL-4和IgA、IgG,而且诱导了高水平的粘膜IgA抗体,末次免疫后第4w其P/N值分别达4.82、4.61、20.58、30.13和6.87;其免疫小鼠外周血CD+4、CD+8T细胞数也显著性升高,分别达56.46%和12.84%;同时,伴有肠壁SIgA的同步性分泌增强。并且,其诱导的特异性免疫应答能有效保护免疫后小鼠免遭空肠弯曲菌的感染攻击,明显减少该细菌的肠道定植和血行扩散,其抑制空肠弯曲菌肠道定植效应为99.3%,其抵御感染向肝脏扩散的效力高达100.0%;显著降低被攻击小鼠周围神经、小肠及肝脏组织的病变发生率。结论空肠弯曲菌多价DNA疫苗在抗空肠弯曲菌感染的过程中具有明显的免疫保护作用。
To investigate the immune protective efficacy of polyvalent DNA vaccines against Campylobacter jejuni （C. jejuni） in mice challenged with C. jejuni invasion, polyvalent DNA vaccines against C. jejunl were prepared by embedding recombinant plasmids pcDNA3. 1 （＋）-cadF and pcDNA3. 1 （＋）-peblA with chitosan. On days 0,7,14 and 21, BALB/c mice were divided to 9 groups and were immunized with various DNA vaccines via nasal administrated. ELISA assay was carried to detect IFN-γ, IL-4 and IgA, IgG from the sera and IgA from the stools in weeks 2,4,6,8 after the last immunization. Flow cytometry assay was carried to detect the numbers of CD4^＋ and CI8^＋ T cells in peripheral blood of mice at the 4th week after the last immunization. Six mice were selected randomly and sacrificed from each group at the 8th week after the last immunization. The expression of intestinal SIgA was detected by immunohistochemistry assay. Mice were attacked singly or repeatedly with intragastric administration of C. jejuni HS ： 2 or HS ： 19 respectively at the 8th week after the last immunization. After loeing attacked with C. jejuni, the immune protective efficacy of the vaccines was assessed including： （1） effect to prevent the event the colonization of C. jejunl in intestine and the spread of C. jejuni to outside of intestine, （2） the histopathology of mice in peripheral nerves,intestines and livers. It was founl that the intrauasal immunization with polyvalent DNA vaccines against C. jejuni generated high levels of IFN-γ, IL-4 and IgA, IgG from the sera and IgA from the stools, and the P/N value went up to 4. 82, 4. 61, 20. 58, 30. 13 and 6.87 respectively. The numbers of CD4^＋ and CD8^＋ T cells were the highest and went up to 56.46% and 12.84% at the 4th week after the last immunization. The expression of intestinal SIgA increased correspondingly. After be attacked with C. jejuni, polyvalent DNA vaccines against C. jejuni group could provide protective efficacy with 99.30% and 100.0 % rates of resistance to intestinal colonization and systemic spread of C. jejunl respectively, meanwhile it could effectively prevent damages in peripheral nerves,intestines and livers. Of the infected mice Polyvalent DNA vaccines against C. jejuni can provide protective efficacy against C. jejuni attack.
出处
《中国人兽共患病学报》
CAS
CSCD
北大核心
2007年第2期115-120,共6页
Chinese Journal of Zoonoses
基金
国家自然科学基金资助项目(30371500)
