The role of IDO in T cell anergy of sodium butyrate-induced immature DC

Abstract

Objective To investigate the role of indoleamine 2,3-dioxygense(IDO) in T cell an-ergy of the immature dendritic cells (DCs) induced by sodium butyrate. Methods Human monecyte-de-rived immature DCs were induced with granulocyte macrophage-colony stimulating factor (GM-CSF) and interleukin-4 (IL-4), and divided into 5 groups on the 6th day. Trizol was added to extract total RNA of each group after 24-h induction. IDO mRNA expression was detected by RT-PCR and real-time PCR. 1-methyl-tryptophan(1-MT) was also used to test mixed lymphocyte reaction in sodium butyrate-induced DCs. Cells were harvested after 96-h incubation and fluorescence intensity was detected by FCM. Results IDO mRNA expression in sodium butyrate group was significantly higher (0.84±0.01) than control group (0.55±0.01) and other mature groups (0.53±0.01) by RT-PCR. The result was further confirmed by real-time PCR. In comparison with the control group,the IDO mRNA expression of DCs was increased by (32.03±4.01) fold. The proliferation of lymphocytes was increased in sodium butyrate group with 1-MT by FCM,which suggested 1-MT may antagonize the inhibition of sodium butyrate-indueed lymphocyte pro-liferation. Conclusion Sodium butyrate may inhibit the lymphocyte proliferation by IDO that can degrada-te amino-indole propionic acid in microenvironment. Key words: Dendritic cell; Indoleamine 2,3-dioxygense; Immunotolerance