Miyaguchi S, Satoh J, Takahashi K, Sakata Y, Nakazawa T, Miyazaki J, Toyota T
Third Department of Internal Medicine, Tohoku University School of Medicine, 1-1 Seiryo-machi, Aoba-ku, Sendai, Miyagi, 980-8574, Japan.
Clin Immunol. 2001 Jan;98(1):119-24. doi: 10.1006/clim.2000.4954.
Systemic administration of human lymphotoxin-alpha (hLT-alpha) made NOD mice resistant not only to spontaneous autoimmune type 1 diabetes mellitus but also to cyclophosphamide (CY)-induced diabetes and diabetes transfer by diabetic NOD spleen cells (triple resistance). In this study we analyzed the mechanisms of hLT-alpha-induced resistance, focusing on (1) hLT-alpha-induced resistance in the pancreatic beta cell, (2) CY-resistant suppressor cells, (3) suppression of induction or function of effector cells for beta cell destruction, or (4) others. To examine the first possibility in vitro, a NOD-derived beta cell line (MIN6N) was pretreated with hLT-alpha and then mixed with diabetic NOD spleen cells and MIN6N cell viability was measured. Treatment with hLT-alpha did not protect MIN6N cells but rather enhanced cytotoxicity. Next NOD-scid mice were pretreated with hLT-alpha and then transferred with diabetic NOD spleen. All the recipients developed diabetes. These results excluded the first possibility. The second possibility was also excluded by a cotransfer experiment, in which diabetic NOD spleen cells were cotransferred to NOD-scid mice with nontreated or hLT-alpha-treated nondiabetic NOD spleens. There was no significant difference in diabetes incidence between the two groups. To observe the third possibility, spleen cells of hLT-alpha-treated triple-resistant NOD mice were transferred to NOD-scid mice. Diabetes developed in the recipients, although the onset of diabetes was slightly delayed. Finally, hLT-alpha-treated triple-resistant NOD mice developed diabetes 1 week after daily IL-12 treatment. In summary, hLT-alpha administration made NOD mice resistant to effector cells for beta cell destruction. This resistance was induced in NOD, but not in NOD-scid, mice, indicating that lymphocytes were obligatory for the resistance. However, it was not mediated by transferable suppressor cells. Because effector cells were present in hLT-alpha-treated NOD spleen and the resistance was abrogated by IL-12 treatment, it is speculated that hLT-alpha treatment may have changed a local cytokine balance protective from beta cell destruction.
全身性给予人淋巴毒素-α（hLT-α）使非肥胖糖尿病（NOD）小鼠不仅对自发性自身免疫性1型糖尿病具有抗性，而且对环磷酰胺（CY）诱导的糖尿病以及糖尿病NOD脾细胞诱导的糖尿病转移具有抗性（三重抗性）。在本研究中，我们分析了hLT-α诱导抗性的机制，重点关注：（1）hLT-α在胰腺β细胞中诱导的抗性；（2）CY抗性抑制细胞；（3）对β细胞破坏效应细胞诱导或功能的抑制；或（4）其他方面。为了在体外研究第一种可能性，用hLT-α预处理源自NOD的β细胞系（MIN6N），然后将其与糖尿病NOD脾细胞混合，并测量MIN6N细胞活力。用hLT-α处理并未保护MIN6N细胞，反而增强了细胞毒性。接下来，用hLT-α预处理NOD-scid小鼠，然后移植糖尿病NOD脾细胞。所有受体均发生糖尿病。这些结果排除了第一种可能性。通过共移植实验也排除了第二种可能性，在该实验中，将糖尿病NOD脾细胞与未处理或经hLT-α处理的非糖尿病NOD脾脏共同移植到NOD-scid小鼠中。两组之间的糖尿病发病率没有显著差异。为了观察第三种可能性，将经hLT-α处理的具有三重抗性的NOD小鼠的脾细胞移植到NOD-scid小鼠中。受体发生了糖尿病，尽管糖尿病的发病稍有延迟。最后，经hLT-α处理的具有三重抗性的NOD小鼠在每日给予白细胞介素-12（IL-12）治疗1周后发生糖尿病。总之，给予hLT-α使NOD小鼠对β细胞破坏效应细胞具有抗性。这种抗性在NOD小鼠而非NOD-scid小鼠中诱导产生，表明淋巴细胞是产生抗性所必需的。然而，它不是由可转移的抑制细胞介导的。由于在经hLT-α处理的NOD脾脏中存在效应细胞，并且抗性通过IL-12治疗而消除，因此推测hLT-α治疗可能改变了局部细胞因子平衡，从而对β细胞破坏起到保护作用。
