Abstract:

Objective To investigate the dynamic changes of SEA?induced specific IgG，IgM in sera of BALB/c mice infect? ed with Schistosoma japonicum in 18 weeks. Methods After mice were infected with S. japonicum cercarial for 2 weeks，the sera were collected from 2 to 18 weeks post?infection. The serum levels of SEA?specific IgG and IgM antibodies were measured respec? tively by ELISA，and the different fractions of IgG and IgM antibodies were identified by the Western blotting method. Results The ELISA results showed that the serum levels of SEA?specific IgG increased 5，6，9，11 week，after the infection，and SEA? specific IgM increased obviously 5，9 weeks after the infection. The Western blotting results showed that 140，180 kDa molecules were recognized by IgG antibodies in the mouse sera 4 weeks after the infection. The specific IgG antibodies of 43，50 kDa anti? gens appeared 5 weeks after the infection. 60-130 kDa fractions were recognized by IgG in the sera 6 weeks post?infection，and 38，73 kDa proteins were recognized by IgG in the sera 9 weeks post?infection. The IgG antibodies of 26，32，35，80 kDa mole? cules appeared 11 weeks post?infection and reacted strongly 12 weeks post?infection. The IgM antibodies of 100，140，180 kDa molecules appeared 3 weeks after the infection，and 73 kDa protein was recognized by sera 6 weeks after the infection，but the re? action became strong 9 weeks after the infection. The 38，43，50 kDa proteins induced IgM antibodies in 9?week?infection sera and the reaction became stronger 9 weeks after the infection. Conclusions There is a dynamic change in the levels of specific IgG and IgM antibodies induced by S. japonica SEA and the appearance of the antibodies is related to different infection stages. The 43，50，10，140，180 kDa antigens might have the potential value of early immunodiagnosis. The 73 kDa antigen shows high diagnostic value in both acute and chronic schistosomiasis. The 28，32，35，38，80 kDa antigens are not only the diagnostic molecules for chronic schistosomiasis， but they may also have therapeutic effects，and in addition，they may be the candidate vac? cines of the disease.

Key words: Schistosoma japonicum；Soluble egg antigen（SEA）； ELISA；Western?blotting； IgG；IgM

摘要：

目的 观察BALB/c小鼠感染日本血吸虫后18周内血清中可溶性虫卵抗原 （SEA） 特异性IgG、 IgM抗体水平的动态变化。方法 尾蚴感染BALB/c小鼠， 感染2周后开始每周采血并分离血清， 以SEA为抗原， 通过ELISA测定不同感染时间血清IgG、 IgM值； 通过免疫印迹法检测不同感染时间小鼠血清中SEA特异性IgG、 IgM抗体条带。结果 ELISA检测结果表明感染小鼠血清IgG水平在感染5、 6、 9、 11周上升明显； IgM在感染5周和9周时上升明显。免疫印迹试验结果表明感染血吸虫4周后， 小鼠血清中开始出现140、 180、 210 kDa蛋白特异性IgG抗体； 感染5周后出现43、 50 kDa强反应IgG特异性抗体带； 感染6周后在60～130 kDa处出现 IgG特异性弥散带； 感染9周后出现38、 73 kDa 蛋白特异性IgG条带， 其中38 kDa 条带较弱， 随感染时间延长， 条带反应逐渐增强， 直至感染18周； 感染11周后新增26、 32、 35、 80 kDa特异性IgG条带， 并且在12周后增强。感染3周后出现100、 140、 180 kDa IgM特异性反应条带， 感染9周后出现73 kDa特异性IgM强反应条带及 38、 43、 50 kDa弱反应IgM抗体带， 后3条蛋白条带随感染时间延长逐渐变强。 结论 SEA中不同组分抗原对感染宿主的免疫调节具有时间特异性， 其中43、 50、 100、 140、 180 kDa具有早期诊断价值； 73 kDa 既可用于急性血吸虫病诊断， 也可用于慢性血吸虫病诊断； 28、 32、 35、 38、 80 kDa抗原既可作为慢性血吸虫感染的优势抗原， 同时也可能具有一定的抗血吸虫感染作用， 可作为疫苗开发的候选抗原。

关键词: 日本血吸虫； 可溶性虫卵抗原； 酶联免疫吸附试验； 免疫印迹法； IgG抗体； IgM抗体