[The regulatory effect of dendritic cells on Th17 cell differentiation and function in mouse infected with Plasmodium yoelii].

Objective: To investigate the regulatory effect of dendritic cells (DCs) on Th17 cell differentiation and function during mouse infection with Plasmodium yoelii 17XL strain (Py17XL) and the underlying mechanisms. Methods: Twelve female BALB/c mice were randomly assigned into the infection group (Py17XL), the TLR4 blocking group (Py17XL + TLR4), TLR9 blocking group (Py17XL + TLR9), and TLR4 and TLR9 combined blocking group (Py17XL + TLR4+TLR9)(n=3 in each group). Mice in the Py17XL + TLR4 or the Py17XL + TLR9 group received intraperitoneal injection of 10 µg anti-TLR4 or 50 µg anti-TLR9 antibody (both 0.4 ml) to block DCs function at one day before infection. The Py17XL group received same volume of PBS. All groups were then given intraperitoneal injection of 1×10(6) red blood cells (RBCs) infected with Py17XL. The RBC infection rate was calculated on days 0, 3 and 5 after infection, and spleen cell suspension was prepared, in which the CD11c+TLR9+ and Th17 cells were counted by flow cytometry. The levels of IFN-γ and IL-10 in supernatant of spleen cell culture were determined by ELISA. Results: Flow cytometry showed that DCs were successfully blocked. On day 5 after infection, 28%,29%, 31% and 16.3% mice showed parasitemia in the Py17XL group, the Py17XL + TLR4 group, the Py17XL + TLR9 group, and the Py17XL + TLR4 + TLR9 group, respectively, and on day 7, the proportions were 43.3%, 47.5%, 32.5% and 8%. Mice in the Py17XL group and the Py17XL + TLR4 group all died, while those in other groups began to die from day 6. There was a slow rise of parasitemia rate in the Py17XL + TLR9 group and the Py17XL + TLR4 + TLR9 group compared with the Py17XL group, with a significant extension of survival to days 11 and 15. Results of flow cytometry showed that the proportions of Th17 cells were 1.2% and 1.44% in the Py17XL + TLR9 group and the Py17XL + TLR4 + TLR9 group on day 5, both sighificantly decreased compared with the Py17XL group (1.9%)(P < 0.05, P < 0.01). ELISA revealed that the levels of IFN-γ and IL-10 on day 5 in the Py17XL + TLR4 + TLR9 group [(232.4 ± 15.5) pg/ml and(1791.2 ± 58.2) pg/ml, respectively] were significantly higher than those in the Py17XL group[(90.7 ± 50.1) pg/ml and (962.6 ± 409.0) pg/ml](P < 0.05, P < 0.01). Conclusions: The differentiation and function of Th17 cells are regulated by DCs during Py17XL infection. Blockade of DCs decreases parasitemia and extends lifetime of mice. Further studies are needed to clarify the exact mechanisms.

[Exploration and Application of Discussion-based Teaching Method in Teaching of Medical Parasitology].

In this study, students majoring in Clinical Medicine were enrolled to explore the effect of discussion-based teaching method in the teaching of medical parasitology. One hundred and fifty-six students (with an entry year of 2011) in classes 1-3 received the discussion-based teaching while 153 students in classes 4-6 received traditional teaching. The effect of teaching was evaluated in terms of final examination score and questionnaire, and compared between the groups. The final examination score of students receiving the discussion-based teaching （86.1±6.6） was significantly higher than those receiving the traditional teaching（74.2±8.3）（P<0.05）. The discussion-based teaching method was graded as "excellent" by 89.1%（136/156）of the students, and was considered to be superior to the traditional teaching by 96.8%（151/156）of the students. The results indicate that the discussion-based teaching method can enhance interactions between participants, change the ways of thinking, and provide inspirations for learning and exploration.