Abstract: 　Objective To study the rat lymphocyte proliferation, differentiation and cytokine production in response to Clonorchis sinensis infection. Methods The lymphocyte proliferation and cytokine production (IFN γ, IL 2, IL 4, IL 10) in response to mitogen phytohaemagglutinin (PHA), C.sinensis excretory secretory antigen (ES Ag), C.sinensis crude antigen (crude Ag) and Anisakis larvae antigen were detected in vitro from splenic lymphocytes (SLC) and mesenteric lymph node cells (MLNC) of rats infected with C.sinensis . Statistical analysis was performed by Sigma Plot System. Results Lymphocyte proliferations in MLNC were higher than that in SLC. At concentrations of 3×10 6 or 9×10 6 cells/well, lymphocyte proliferations were significantly higher in both SLS and MLNC than in the control with cell alone ( P <0.01). At the lymphocyte concentration of 5×10 6 cells/well and stimulator concentration of 5 or 10 μg/ml, significant lymphocyte activation was observed. Under the same culture condition (5×10 6 cells/well with 10 μg/ml stimulator ), cytokine IFN γ and IL 10 production in vitro increased significantly in MLNC. Conclusion Concentrations of 5×10 6 lymphocytes/well and 10 μg/ml stimulator were selected as the optimal culture condition for activation of lymphocyte proliferation and cytokine production. Since the production of Th1 type cytokine IFN γ and Th2 type cytokine IL 10 was much enhanced from MLNC of C.sinensis infected rats, it is considered that C.sinensis ES Ag may stimulate lymphocyte proliferation and cytokine production in C.sinensis infected rats in vivo .

Key words: Clonorchis sinensis, cytokine, IFN γ, IL 2, IL 4, IL 10, lymphocyte proliferation