Laboratory of Experimental Surgery, Research Centre, Center Hospitalier de l'Université de Montréal-Hôpital Notre-Dame, Department of Surgery, University of Montreal, Montréal, Québec, Canada.
Int Immunopharmacol. 2011 May;11(5):618-29. doi: 10.1016/j.intimp.2010.11.001. Epub 2010 Nov 20.
Although donor alloantigen specific Treg cells play an important role in transplant tolerance, therapeutic applications are limited by their low frequency. In this study, isolated Tregs from Cynomolgus monkeys were efficiently expanded by a co-culture system, and maintained suppressive function on the proliferation of CD4(+) effector cells in vitro. Adoptive transfer of expanded donor alloantigen specific Tregs without any immunosuppressants could prolong survival of MHC-mismatched allografts in Cynomolgus monkeys. To reach the feasibility of clinical transplantation, our objectives focused on whether exposure of monkey Tregs to immunosuppressants could preserve suppressive function in vitro and in vivo. The results showed that low-dose sirolimus selectively expanded Tregs, increased the expression of CD25(bright) and Foxp3 markers, and suppressed TCR- or allo-antigens induced CD4(+) T cell proliferation in vitro. In vivo, after pre-treated with anti-thymocyte globulin (ATG) for consecutive 3days, a 14-day therapy of adoptive infusion of donor alloantigen-specific Tregs combined with low-dose sirolimus delayed acute rejection of renal allografts in Cynomolgus monkeys, showing an MST of 48.5days as compared with those of untreated and sirolimus-treated monkeys (7days and 22days). The frequencies of CD4(+)CD25(bright) T cells were significantly elevated in mesenteric lymph nodes vs. those in inguino lymph nodes and peripheral blood. In summary, expanded donor alloantigen specific Tregs exposed to sirolimus can preserve inhibition in vitro and in vivo. Tregs are more resistant to sirolimus than other T cells. Expanded donor alloantigen specific Tregs combined with sirolimus and ATG prolongs renal allograft survival in monkeys, suggesting that sirolimus might be one of the best synergists for Tregs therapy.
虽然供体同种抗原特异性调节性 T 细胞在移植耐受中发挥重要作用，但由于其频率较低，治疗应用受到限制。在这项研究中，通过共培养系统有效地扩增了食蟹猴的分离 Treg，并在体外维持对 CD4+效应细胞增殖的抑制功能。在没有任何免疫抑制剂的情况下，过继转移扩增的供体同种抗原特异性 Treg 可以延长 MHC 错配同种异体移植物在食蟹猴中的存活时间。为了达到临床移植的可行性，我们的目标集中在猴 Treg 暴露于免疫抑制剂是否可以在体外和体内保持其抑制功能。结果表明，低剂量西罗莫司选择性地扩增了 Treg，增加了 CD25(bright)和 Foxp3 标志物的表达，并抑制了 TCR 或同种抗原诱导的 CD4+T 细胞在体外的增殖。在体内，在用抗胸腺细胞球蛋白（ATG）连续预处理 3 天后，采用同种抗原特异性 Treg 过继输注联合低剂量西罗莫司进行 14 天治疗，可延迟食蟹猴肾移植的急性排斥反应，与未治疗和西罗莫司治疗的猴子相比，其 MST 为 48.5 天（7 天和 22 天）。肠系膜淋巴结中 CD4+CD25(bright)T 细胞的频率明显高于腹股沟淋巴结和外周血中的频率。总之，暴露于西罗莫司的扩增供体同种抗原特异性 Treg 可以在体外和体内保持抑制作用。Treg 比其他 T 细胞对西罗莫司更有抵抗力。与西罗莫司和 ATG 联合使用扩增的供体同种抗原特异性 Treg 可延长猴子的肾移植存活时间，这表明西罗莫司可能是 Treg 治疗的最佳协同剂之一。
