Abstract: Objective To investigate the effect of Trichinella spiralis infection on dectin-2 expression on dendritic cells（DC） in mice. Methods Seventy-two female BABL/c mice were randomized into experimental and control groups（n=36 in each）, and received intragastric administration of 200 muscle larvae of Trichinella spiralis and PBS respectively. Six animals were each sacrificed on days 7, 14, 21, 28, 35 and 42 after administration. The spleen and mesenteric lymph nodes（MLN） were dissected and single cell suspensions were prepared. The expression of dectin-2 on DC in the spleen and MLN was examined by flow cytometry. In another experiment, bone marrow was obtained from C57BL/6 mice, and was treated with granulocyte-macrophage colony-stimulating factor and interleukin 4 to induce bone marrow-derived dendritic cells（BMDC） in vitro. Then 100 μg/ml T. spiralis excretory/secretory（ES） antigen or the same volume of PBS was added. The expression of dectin-2 was determined by flow cytometry at 6, 12, 24, 36 and 48 h. Results The flow cytometry results showed a significant decrease of dectin-2 expression［（7.0±0.7）%］ on spleen DC compared with that of the control group［（15.1±1.6）%］（P<0.01） on day 7, and significant increase of dectin-2 on MLNDC compared with that of the control on days 7, 21 and 28 ［（11.1±3.5）% vs. （6.6±0.4）%, （12.4±1.4）% vs. （4.9±0.4）%, （6.9±1.0）% vs. （4.0±1.4）%］ （P<0.05） after infection. In vitro results showed that dectin-2 expression was （9.4±2.2）%, （6.9±1.8）%, （6.9±0.7）%, （9.1±1.9）%, and（15.9±1.9）% respectively at 6, 12, 24, 36, and 48 h after ES stimulation on BMDC. The expression at 6, 12, 24 and 36 h decreased significantly in comparison to that of the PBS group［（21.3±6.3）%］（P<0.01）. Conclusion Trichinella infection can induce changes of dectin-2 expression on DC of mice.

Key words: Trichinella spiralis, Excretory/secretory antigens, Dendritic cell, Dectin-2