Saï P, Rivereau A S, Granier C, Haertlé T, Martignat L
Laboratory of Cellular and Molecular Immuno-Endocrinology, INRA/ENVN, University School of Medicine, Nantes, France.
Clin Exp Immunol. 1996 Aug;105(2):330-7. doi: 10.1046/j.1365-2249.1996.d01-751.x.
NOD mice constitute a model for studying the prevention of human autoimmune type 1 diabetes. Glutamic acid decarboxylase (GAD) could be a key antigen involved in this disease, and GAD65 peptide 524-543 has been implicated in early T cell response in young NOD mice. We performed two i.p. injections of GAD peptide 524-543 (100 micrograms at each injection), together with Freund's incomplete adjuvant (FIA), into female NOD mice at 30 and 45 days old. Diabetes was accelerated 2 weeks later by a single injection of cyclophosphamide (CY), which acts against suppressive mechanisms. Treatment with GAD 524-543 peptide delayed the onset of diabetes and reduced its incidence (28% versus 60%; P < 0.001) compared with control mice injected with FIA alone, or GAD peptide 534-553, or an irrelevant peptide. In the same group, the severity of lymphocytic inflammation of pancreatic islets was reduced (P < 0.03). Up to 3 months after peptide injections, a strong splenocytic proliferative response occurred in immunized NOD mice against the immunizing peptide alone (but not against a panel of seven other GAD65-derived peptides). After peptide challenge of splenocytes in vitro, protection against CY-accelerated diabetes was associated with higher peptide-specific production of T helper type 2 (Th2)-associated interleukins 4 and 10, whereas Th1-associated interferon-gamma and IL-2 were proportionally less represented. During contransfer, T splenocytes from GAD 524-543-immunized mice were able to reduce the capacity of T cells from diabetic donors to transfer the disease adoptively (P < 0.01), demonstrating the generation of cellular mechanisms that actively suppress the disease. It is concluded that immunization of NOD mice with GAD65 peptide 524-543 can counteract CY-accelerated diabetes, possibly through active cellular suppression linked to a shift of Th1/Th2 balance toward the production of Th2 cytokines such as IL-4 and IL-10. This study provides additional support for the notion that GAD, and more precisely its epitope 524-543, could be one of the key targets for the pathogenesis of type 1 diabetes in NOD mice, as well as for the efficacy of disease-specific peptide therapy in type 1 diabetes.
非肥胖糖尿病（NOD）小鼠构成了研究人类自身免疫性1型糖尿病预防的模型。谷氨酸脱羧酶（GAD）可能是参与该疾病的关键抗原，并且GAD65肽524 - 543与年轻NOD小鼠的早期T细胞反应有关。我们在30日龄和45日龄时，将GAD肽524 - 543（每次注射100微克）与弗氏不完全佐剂（FIA）一起腹腔注射到雌性NOD小鼠体内。两周后通过单次注射环磷酰胺（CY）加速糖尿病的发生，环磷酰胺作用于抑制机制。与单独注射FIA、GAD肽534 - 553或无关肽的对照小鼠相比，用GAD 524 - 543肽治疗延迟了糖尿病的发病并降低了其发病率（28%对60%；P < 0.001）。在同一组中，胰岛淋巴细胞炎症的严重程度降低（P < 0.03）。在肽注射后长达3个月的时间里，免疫的NOD小鼠中出现了针对单独免疫肽（但不针对一组七种其他GAD65衍生肽）的强烈脾细胞增殖反应。在体外对脾细胞进行肽攻击后，对CY加速的糖尿病的保护作用与较高的肽特异性产生的2型辅助性T细胞（Th2）相关白细胞介素4和10有关，而Th1相关的干扰素 - γ和IL - 2的比例相对较低。在共转移期间来自GAD 524 - 543免疫小鼠的T脾细胞能够降低来自糖尿病供体的T细胞过继转移疾病的能力（P < 0.01），表明产生了积极抑制该疾病的细胞机制。得出的结论是，用GAD65肽524 - 543免疫NOD小鼠可以抵消CY加速的糖尿病，可能是通过与Th1/Th2平衡向产生Th2细胞因子如IL - 4和IL - 10的转变相关的主动细胞抑制。这项研究为GAD，更确切地说是其表位524 - 543可能是NOD小鼠1型糖尿病发病机制的关键靶点之一以及疾病特异性肽疗法在1型糖尿病中的疗效提供了额外的支持。
