Proliferation and cytokine production of lymphocytes from Clonorchis sinensis-infected rats in response to stimulators in vitro.

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-gamma, 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 x 10(6) or 9 x 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 x 10(6) cells/well and stimulator concentration of 5 or 10 micrograms/ml, significant lymphocyte activation was observed. Under the same culture condition (5 x 10(6) cells/ well with 10 micrograms/ml stimulator), cytokine IFN-gamma and IL-10 production in vitro increased significantly in MLNC. CONCLUSION: Concentrations of 5 x 10(6) lymphocytes/well and 10 micrograms/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-gamma 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.