日本血吸虫童虫细胞与非细胞型免疫原在小鼠免疫部位滞留的动态观察

Dynamic observation of the persistence of cell-type and non-cell-type immunogens from Schistosomulum in immunized mice

目的观察日本血吸虫(Schistosoma japonicum,Sj)童虫细胞型免疫原和童虫细胞碎片免疫原免疫小鼠后在免疫部位滞留的动态变化。方法昆明鼠实验组A和B经大腿肌肉分别注射107日本血吸虫原代童虫细胞(pJCs)和相当剂量的童虫细胞碎片(JCFs),对照组C注射PBS。分别在注射后1、3、6、9和12 d,各组随机处理4或2只小鼠,从注射部位定量获取肌肉组织,用Western blot法和免疫组化法观察、比较两种类型抗原滞留的动态变化;用组织病理学方法观察发生的炎症反应。结果Western blot显示,A组在注射后各时间点均检测到分子质量单位为75 ku的特异性抗原条带,B组在注射后第6 d该条带即消失,C组未检出该条带。免疫组化检测结果与Western blot相符。组织病理学检查结果显示,A组在免疫后第12 d仍可见肌细胞间隙内大量炎性细胞浸润,B组在免疫后第12 d炎性细胞基本消失,C组未见炎性反应。结论血吸虫童虫细胞型免疫原较童虫细胞碎片免疫原在免疫部位可滞留更长时间,引起更持久的炎性反应,这可能是其诱生高保护性抗血吸虫病免疫的重要机制之一。

Objective To observe the kinetics of persistence of immunogens in mice immunized with primary juvenile worm cells （pJCs） or fractions of juvenile worm cells （JCFs） from Schistosoma japonicum. Methods Kunming mice in test groups A and B and control group C were intramuscularly injected with 107 pJCs or an equivalent amount of JCFs and PBS, respectively. On days 1, 3, 6, 9, and 12 after injection, 4 mice in test groups or 2 mice in control group were trea ted. and muscular tissues were quantitatively obtained from immunization sites in order to observe and compare the persistence of immunogens in immunized mice by Western blotting and immunohistochemistry and to examine inflammatory response using histopathology. Results In group A, Western blotting revealed a 75 ku specific Sj antigen band that was detected in the muscular tissues at all time points after immunization although this band disappeared in group B on day 6 after immunization. No bands were detected in group C. Immunohistochemistry results agreed with those of Western blotting. Histopathological results revealed a large number of inflammatory cells in muscle interstitial spaces on day 12 after injection in group A but these cells disappeared on day 12 in group B. No inflammatory cell infiltration was found in group C at any time point. Conclusion The immunogen of pJCs may remain for a longer time at the immunization site and provoke a longer-lasting inflammatory response than that of JCFs, which may be an important mechanism for the induction of protective immunity against schistosomiasis.