Di Ianni Mauro, Del Papa Beatrice, De Ioanni Maria, Moretti Lorenzo, Bonifacio Elisabetta, Cecchini Debora, Sportoletti Paolo, Falzetti Franca, Tabilio Antonio
Hematology and Clinical Immunology Section, Department of Clinical and Experimental Medicine, University of Perugia, Italy.
Exp Hematol. 2008 Mar;36(3):309-18. doi: 10.1016/j.exphem.2007.11.007.
Despite much investigation into T regulatory cells (Tregs), little is known about the mechanism controlling their recruitment and function. Because multipotent mesenchymal stromal cells (MSCs) exert an immune regulatory function and suppress T-cell proliferation, this in vitro study investigated their role in Treg recruitment and function.
Human MSCs and different T cell populations (CD3(+), CD3(+)/CD45RA(+), CD3(+)/CD45RO(+), CD4(+)/CD25(+), CD4(+)/CD25(+)/CD45RO(+), CD4(+)/CD25(+)/CD45RA(+)) from healthy donors were cocultured for up to 15 days. Harvested lymphocytes were analyzed by flow cytometry and FoxP3 and CD127 expressions were measured by real-time polymerase chain reaction. Their regulatory activity was assessed.
We demonstrate MSC recruit Tregs from a fraction of CD3(+) and from immunoselected CD3(+)/CD45RA(+) and CD3(+)/CD45RO(+) fractions. After culture with MSCs both immunoselected fractions registered increases in the CD4(+)/CD25(bright)/FoxP3 subset and CD127 expression was downregulated. When purified Treg populations (CD4/CD25(+), CD4/CD25(+)/CD45RA(+), and CD4/CD25(+)/CD45RO(+)) are used in MSC cocultures, they maintain FoxP3 expression and CD127 expression is downregulated. Treg suppressive capacity was maintained in Treg populations that were layered on MSC for up to 15 days while control Tregs lost all suppressive activity after 5 days culture.
In conclusion, our study demonstrates that MSCs recruit, regulate, and maintain T-regulatory phenotype and function over time.
尽管对调节性T细胞（Tregs）进行了大量研究，但对控制其募集和功能的机制仍知之甚少。由于多能间充质基质细胞（MSCs）发挥免疫调节功能并抑制T细胞增殖，本体外研究探讨了它们在Treg募集和功能中的作用。
将来自健康供体的人MSCs与不同的T细胞群体（CD3(+)、CD3(+)/CD45RA(+)、CD3(+)/CD45RO(+)、CD4(+)/CD25(+)、CD4(+)/CD25(+)/CD45RO(+)、CD4(+)/CD25(+)/CD45RA(+)）共培养长达15天。通过流式细胞术分析收获的淋巴细胞，并通过实时聚合酶链反应测量FoxP3和CD127的表达。评估它们的调节活性。
我们证明MSCs从一部分CD3(+)以及免疫选择的CD3(+)/CD45RA(+)和CD3(+)/CD45RO(+)部分募集Tregs。与MSCs共培养后，两个免疫选择部分中CD4(+)/CD25(bright)/FoxP3亚群均增加，且CD127表达下调。当将纯化的Treg群体（CD4/CD25(+)、CD4/CD25(+)/CD45RA(+)和CD4/CD25(+)/CD45RO(+)）用于与MSCs共培养时，它们维持FoxP3表达，且CD127表达下调。在MSCs上分层培养长达15天的Treg群体中，Treg抑制能力得以维持，而对照Tregs在培养5天后失去了所有抑制活性。
总之，我们的研究表明MSCs随着时间的推移募集、调节并维持T调节表型和功能。
