SPONTANEOUS DIABETES--PATHOGENESIS AND TREATMENT

糖尿病中β细胞的破坏被认为是由失败引起的 自身反应性T细胞不能进行阴性反应， 胸腺内成熟过程中的选择。我们发现植入 少量的β细胞进入新生儿糖尿病患者的胸腺， BB大鼠阻止了预期的胰岛自身免疫性破坏， 原生胰腺这为我们解剖 胰岛复合体，以确定特定的自身抗原成分 胰岛是糖尿病的目标，因此也可以是 可用于免疫治疗。胰岛的细胞成分（内分泌细胞与 抗原呈递细胞）和亚细胞成分（谷氨酸 脱羧酶和胰岛素）将被评估为可能的致糖尿病性 自身抗原 我们将用全胰岛、APC和免疫球蛋白（IgG）对新生BB大鼠胸腺进行免疫球蛋白（IgG）检测， 游离胰岛、GAD蛋白、胰岛素和非胰岛细胞表达 GAD（神经元细胞）或胰岛素（垂体细胞遗传学） 工程化以产生胰岛素）。接收者将受到监控， 这些治疗方法，比如胸腺内接种 胰岛，对糖尿病的发展有保护作用。 在我们初步的免疫组织化学研究中， 移植表达GAD的神经元细胞的胸腺是 胸腺细胞本身也表达GAD。另一项观察是， BB大鼠胸腺内GAD表达的解剖模式不同 和正常大鼠的关系很有趣，可能有病因学的意义。 通过分子检测，我们将确认胸腺GAD的存在。我们将 研究GAD在其他正常人和糖尿病易感者胸腺中的表达 动物（例如NOD小鼠），以确定观察结果的一般性。我们 还将研究GAD表达的胸腺模式是否可以 通过已知可预防BB大鼠糖尿病的方法进行标准化，例如交叉 与正常大鼠交配，新生大鼠骨髓移植， 正常捐赠者 有些难以调和GAD的关键重要性， 关键的致糖尿病自身抗原（而不是预期的 缺乏）从糖尿病易感大鼠的胸腺，除非有缺陷的胸腺内 这种自身抗原在BB大鼠中的呈递阻止了它们的能力， 阴性选择β细胞自身反应性T细胞。这种可能性将是 通过将正常的抗原呈递细胞引入胸腺， BB老鼠 由于我们可以通过新生BB大鼠的胸腺操作来预防糖尿病， 我们还将探索这些策略在急性胰腺炎动物中的应用。 以确定自身免疫攻击下的胰岛是否可以 获救了类似的方法也将用于老年动物， 自从这些方法最终应用于人类以来， 可能无法用于新生儿。后一项研究将 包括预防同种异体排斥和/或自身免疫的新方法 使用环状CD 4肽破坏移植的胰岛 模拟

Destruction of beta cells in diabetes is thought to be caused by a failure of self-tolerance whereby autoreactive T cells fail to undergo negative selection during intrathymic maturation. We have found that implantation of a small number of beta cells into the thymus of neonatal diabetes-prone BB rats prevents the expected autoimmune destruction of islets in the native pancreas. This provides us with an ideal model for dissection of the islet complex to define the specific autoantigenic component(s) of islets which are the targets of diabetes and which therefore could also be useful in immunotherapy. Cellular components of islets (endocrine cells vs antigen presenting cells) and subcellular elements (glutamic acid decarboxylase and insulin) will be evaluated as the likely diabetogenic autoantigens. We will inoculate the thymus of neonatal BB rats with whole islets, APC free islets, GAD protein, insulin, and non-islet cells which express either GAD (neuronal cells) or insulin (pituitary cells genetically engineered to produce insulin). Recipients will be monitored to determine whether any of these treatments, like intrathymic inoculation of whole islets, has a protective influence on the development of diabetes. A surprising finding made in our preliminary immunohistochemical search of the thymus for transplanted neuronal cells which express GAD was that thymic cells themselves also express GAD. The additional observation that the anatomical pattern of intrathymic expression of GAD differs in BB rats and normal rats is intriguing and could have etiological implications. With molecular assays we will confirm the presence of thymic GAD. We will study GAD expression in the thymus of other normal and diabetes-prone animals (e.g. NOD mice) to determine the generality of the observation. We will also study whether the thymic pattern of GAD expression can be normalized by maneuvers known to prevent diabetes in BB rats, e.g. cross breeding with normal rats, neonatal transplantation of bone marrow from normal donors. t is somewhat difficult to reconcile the crucial importance of GAD as the key diabetogenic autoantigen with its presence (rather than expected absence) from the thymus of diabetes prone rats, unless faulty intrathymic presentation of this autoantigen in BB rats prevents their ability to negatively select beta cell autoreactive T cells. This possibility will be explored by inoculating normal antigen-presenting cells into the thymus of BB rats. Since we can prevent diabetes by thymic manipulation of neonatal BB rats, we will also explore the use of these strategies in animals with acute onset diabetes to determine whether islets under autoimmune attack can be rescued. Similar methods will also be employed in older animals with established diabetes since eventual human application of these methods could probably not be employed in newborns. The latter studies will include novel methods of preventing allogeneic rejection and/or autoimmune destruction of transplanted islets with the use of a cyclic CD4 peptide analogue.