关键词: 日本血吸虫, Th2免疫应答, 抗原提呈细胞

Abstract: Objective  To observe the changes in various dendritic cell （DC） subsets, macrophages, basophils, eosinophils and mast cells in mouse spleen before and after Schistosoma japonicum infection induced Th2 response.  Methods  C57BL/6 mice were infected with 20 S. japonicum cercariae via abdominal skin. Before infection and at 2, 4, and 6 weeks post-infection, the mice were sacrificed and spleen was removed. The frequencies of non-T, non-B basophils （NTNB）, eosinophils, mast cells, subsets of DC and macrophages in the spleen were measured by flow cytometry.  Results   At 4 weeks after infection, when Th2 cells started to occur, the proportion of CD11c+CD8+DC and CD11c+CD4+DC in B220-CD11c+DC increased from 7.4% and 7.9% before infection to 17.1% and 12.0%, respectively. During the infection, CD11c+CD4-CD8-DC, the majority of B220-CD11c+DC, remained on a nearly constant level（70%）; the percentage of B220+CD11c+ DC in NTNB decreased. The macrophages were subdivided into two subsets: F4/80+CD11bint and F4/80+CD11bhigh. The percentage of F4/80+CD11bint and F4/80＋CD11bhigh in NTNB dropped from 15.4% and 13.7% before infection to 2.7% and 8.6% at 4 weeks post-infection. The proportion of CD11b high macrophages in F4/80+ cells significantly increased from 47.1% before infection to 75.5% at 4 weeks after infection. During S. japonicum infection, eosinophil percentage in the spleen gradually increased, while the frequency of basophils and mast cells in NTNB greatly decreased.  Conclusion  At the time when Th2 response starts to occur, the frequency of CD11c+CD8+DC and CD11c+CD4+DC in CD11c+ dendritic cells increases. Once Th2 immune response established, the eosinophil frequency increases.

Key words: Schistosoma japonicum, Th2 response, Antigen-presentation cell