中文摘要：

目的探讨吲哚胺2，3双加氧酶（IDO）抑制T细胞增殖的机制。方法通过低色氨酸（10μmol／L）培养基（LTM）和／或添加不同浓度（50、100、200和400μmlol／L）色氨酸代谢产物（TC），观察小鼠树突细胞（DC）与异系CD4＋T细胞培养体系中后者的增殖。Annexin-V及碘化丙锭（PI）双染法测定CD4＋T细胞凋亡。结果LTM中CD4＋T细胞增殖指数（2．718±0．010）及抑制CD4＋T细胞增殖的TC浓度（200μmol／LKYN或50μmol／L3-HAA）较正常色氨酸培养基（NTM）（3．385＋0．013，400μmoL／LKYN或100μmol／L3-HAA）显著降低，差异有统计学意义（P〈0．01）。LTM中CD4＋T细胞早期凋亡率（33．163±0．556）％显著高于NTM（8．867＋0．565）％（P〈0．01）。NTM中CD4＋T细胞凋亡率随3-HAA浓度升高而增加[3-HAA浓度50、100、200和400μmol／L组中分别为（14．433±0．640）％、（22．273±0．629）％、（37．363±0．953）％和（46．643±0．633）％]。结论LTM及TC均可通过诱导凋亡来抑制CD4＋T细胞增殖，两者具有叠加效应。

英文摘要：

Objective To reveal the mechanism of inhibitory effect on CD4＋T lymphocytes proliferation by indoleamine 2,3-Dioxygenase （IDOl. Methods Low-Tryptophan medium （ 10μmol/L） and/ or Tryptophan catabolites （50, 100,200 and 400μmol/L） were used to observe CD4 ± T lymphocytes pro liferation in a mixed culturing system with murine dentritic cells （DC） and allogeneic CD4＋ lymphocytes in vitro. Annexin-V and PI double staining method was used to determine CD4＋ lymphocytes apoptosis. Results Stimulation index in low-Tryptophan medium group （2. 718 ± 0. 010） was decreased significantly （P 〈 0. 01 ） as compared with that in normal Tryptophan medium group （3. 385 ± 0.013）. The inhibitory concentrations of Tryptophan eatabolites in low-Trptophan medium group （200 μmol/L KYN or 50 μmol/L 3-HAA） were lower significantly than those in nomal Trptophan medimn group （400 μmol/L KYN or 100 p, mol/L 3-HAA）. Apoptosis rate of CD4 ~T cells in low-tryptophan medium goup （33. 163 ± 0. 556）% was significantly higher （P 〈 0. 01 ） than that in the control group （ 8. 867 ± 0. 565 ） %. The apoptosis rate was increased with the increase in concentrations of Tryptophan catabolites [ （ 14. 433 ± 0. 640 ） % , （22. 273 ±0. 629）%, （37. 363 ±0. 953）% and （46. 643 ±0. 633）% in the medium of 50, 100, 200 and 400 μmol/L of 3-HAA ]. Conclusion Low-tryptophan medium and tryptophan eatabolites both can inhibit the proliferation of CD4 ± T lymphocytes by inducing apoptosis.