1 Transplantation Research Immunology Group, Nuffield Department of Surgical Sciences, John Radcliffe Hospital, University of Oxford, Oxford, UK. 2 Currently, Department of Clinical Immunology and Transplantology, Medical University of Gdansk, Gdansk, Poland. 3 Address correspondence to: Professor Kathryn J. Wood, D.Phil., Transplantation Research Immunology Group, Nuffield Department of Surgical Sciences, John Radcliffe Hospital, University of Oxford, Oxford OX3 9DU, UK.
Transplantation. 2013 Oct 27;96(8):707-16. doi: 10.1097/TP.0b013e31829fa271.
Human regulatory T cells (Treg) offer an attractive adjunctive therapy to reduce current reliance on lifelong, nonspecific immunosuppression after transplantation. Here, we evaluated the ability of ex vivo expanded human Treg to prevent the rejection of islets of Langerhans in a humanized mouse model and examined the mechanisms involved.
We engrafted human pancreatic islets of Langerhans into the renal subcapsular space of immunodeficient BALB/c.rag2(-/-).cγ(-/-) mice, previously rendered diabetic via injection of the β-cell toxin streptozocin. After the establishment of stable euglycemia, mice were reconstituted with allogeneic human peripheral blood mononuclear cells (PBMC) and the resultant alloreactive response studied. Ex vivo expanded CD25high CD4+ human Treg, which expressed FoxP3, CTLA-4, and CD62L and remained CD127low, were then cotransferred together with human PBMC and islet allografts and monitored for evidence of rejection.
Human islets transplanted into diabetic immunodeficient mice reversed diabetes but were rejected rapidly after the mice were reconstituted with allogeneic human PBMC. Cotransfer of purified, ex vivo expanded human Treg prolonged islet allograft survival resulting in the accumulation of Treg in the peripheral lymphoid tissue and suppression of proliferation and interferon-γ production by T cells. In vitro, Treg suppressed activation of signal transducers and activators of transcription and inhibited the effector differentiation of responder T cells.
Ex vivo expanded Treg retain regulatory activity in vivo, can protect a human islet allograft from rejection by suppressing signal transducers and activators of transcription activation and inhibiting T-cell differentiation, and have clinical potential as an adjunctive cellular therapy.
人类调节性 T 细胞（Treg）为减少移植后对终生、非特异性免疫抑制的依赖提供了一种有吸引力的辅助治疗方法。在这里，我们评估了体外扩增的人类 Treg 预防胰岛细胞在人源化小鼠模型中排斥的能力，并研究了所涉及的机制。
我们将人类胰岛细胞植入免疫缺陷 BALB/c.rag2(-/-).cγ(-/-)小鼠的肾被膜下腔，这些小鼠先前通过注射β细胞毒素链脲佐菌素而导致糖尿病。在建立稳定的血糖正常后，用同种异体人外周血单核细胞（PBMC）重建小鼠，并研究由此产生的同种异体反应。然后共转染体外扩增的 CD25high CD4+人类 Treg，其表达 FoxP3、CTLA-4 和 CD62L，并且仍然 CD127low，与人类 PBMC 和胰岛同种异体移植物一起，并监测排斥的证据。
将人类胰岛移植到糖尿病免疫缺陷小鼠中可逆转糖尿病，但在小鼠用同种异体人 PBMC 重建后迅速被排斥。纯化的体外扩增人类 Treg 的共转染延长了胰岛同种异体移植物的存活时间，导致 Treg 在周围淋巴组织中的积累，并抑制 T 细胞的增殖和干扰素-γ的产生。在体外，Treg 抑制转录激活物和激活物的激活，并抑制效应 T 细胞的分化。
体外扩增的 Treg 在体内保留了调节活性，可通过抑制转录激活物和激活物的激活以及抑制 T 细胞分化来保护人类胰岛同种异体移植物免受排斥，具有作为辅助细胞治疗的临床潜力。
