关键词: 日本血吸虫, 致弱尾蚴, 调节性T细胞, 转录因子Foxp3, 免疫调节

Abstract:

Objective To study the CD4+CD25+Foxp3+Treg cells’ expression differences between the attenuated cercariae immunized mice and the normal infected mice and discuss the immune protection mechanisms of the mice immunized with attenuated cercariae. Methods Forty female BALB/c mice were divided into 2 groups, group A, the attenuated cercariae immunized group (16 ones) and the group B, the normal cercariae infected group (16 ones), and the last 8 ones served as the blank control. The spleen cells and the ratios of PBMC’s CD4+CD25+Foxp3+/CD4+CD25+T cells were compared between the attenuated cercariae immunized mice and normal mice infected by FCM and the Foxp3 expression levels in spleens and livers were assayed by IHC. The transcription factor Foxp3 in the peripheral blood was detected by RT-PCR. Results In group A and group B, CD4+CD25+Foxp3+/CD4+CD25+T ratios in the PBMC 6 weeks post-infection were （14.15±2.62）% and (7.92±2.22）% respectively, P<0.05; the ratios in the spleen cells were (14.52±2.98)% and (8.18±2.84)% respectively, P<.05; 8 weeks post-infection, the ratios in the PBMC were （15.92±2.98）% and;(13.26±2.64）% respectively, P<0.05; the ratios of the spleen cells were (16.42±2.46)% and (13.48±2.36)% respectively, P<0.05; 6 weeks post-infection, the Foxp3 expression levels in livers were “+” and“-” respectively, and those in the spleens were “++” and“+” respectively; 8 weeks post-infection, the Foxp3 expression levels in the livers were “++” and“-” respectively, and those in the spleens were “++” and“+” respectively. Conclusions The expression level of attenuated cercariae immunized group’s CD4+CD25+Foxp3+Treg cells is higher than that in the control group during the late stages, suggesting that CD4+CD25+Foxp3+Treg in the attenuated cercariae immunized mice may play one of the important roles in its immune protection mechanisms.

Key words: Schistosoma japonicum, Attenuated cercariae, T regulatory cells, Transcription factor Foxp3, Immune regulation