B-lymphocyte Targeting Therapies for Autoimmune Diabetes

项目摘要/摘要 在NOD小鼠模型中，也可能在人类中，B淋巴细胞在1型糖尿病(T1D)中发挥关键作用 通过充当抗原提呈细胞(APC)的子集来最有效地支持 自身反应性T细胞最终介导了胰岛细胞的破坏。然而，一项临床试验发现，B- 淋巴细胞耗竭CD20特异性利妥昔单抗作为一种可能的T1D只有部分疗效 干预。在不排除其他可能的促成因素的同时，我们发现B淋巴细胞进入 NOD小鼠的胰岛下调细胞表面CD20的表达可能部分解释了为什么 利妥昔单抗治疗并不代表强有力的T1D干预。目前只有可能考虑 在已经形成持续攻击性标志的人类中启动可能的T1D干预 病理性自身免疫，如胰岛素自身抗体(IAA)的存在。因此，这一行动的中心目标是 建议确定其他可能的B淋巴细胞导向方法，无论是独立的还是 与抗CD20协同作用提供了比那些 先前评估过的。我们发现，当NOD小鼠在已经呈IAA阳性的晚期启动时， 用可溶性受体试剂阻断B淋巴细胞存活的疾病发展一过性治疗 BAFF因子能有效抑制T1D发育。我们的新目标1是测试由 初步数据显示，除了被清除的那些具有致病APC活性的人外，B淋巴细胞 NOD小鼠在短暂的BAFF阻断转变为T1D保护后保持存在和/或反弹 免疫调节表型，如果是这样的话，这可能是如何机制发生的。可能的B淋巴细胞靶向 对T1D的方法也可能通过更好地了解特定的自身抗原而得到帮助。 导致疾病的特定人群及其异常发育的遗传基础。在这 关于这一点，我们发现B淋巴细胞转基因表达一种免疫球蛋白(Ig)分子 胰岛自身抗原外周蛋白介导NOD小鼠T1D发育速度显著加快 (股票指定为Nod-PerIg)。该Nod-PerIg股票提供了在目标2中检验假设的关键资源 其他初步数据支持亚型EphB2等位基因变异代表T1D易感性 (IDD)基因通过促进致病B淋巴细胞的发育而在NOD小鼠中表达。NOD小鼠致虚 在启动B淋巴细胞亲和力成熟过程的Aicda基因中，对T1D具有深刻的抗性。 此外，一种名为DIDS的小分子治疗也会抑制B淋巴细胞的亲和力成熟 在已经IAA阳性的NOD小鼠中启动时，阻止进展到显性T1D。目标3将测试可能性 初步数据支持Aicda缺乏症或DIDs是否仍存在B淋巴细胞 NOD小鼠通过免疫抑制CD73胞外酶和/或IL-10的产生抑制T1D， 并评估这些因素是否也与人类的疾病调控有关。

PROJECT SUMMARY/ABSTRACT In both the NOD mouse model, and also likely humans, B-lymphocytes play a key role in type 1 diabetes (T1D) development by serving as a subset of antigen presenting cells (APC) most efficiently supporting expansion of autoreactive T-cells ultimately mediating pancreatic ß-cell destruction. However, a clinical trial found the B- lymphocyte depleting CD20 specific rituximab antibody was only partially effective as a possible T1D intervention. While not excluding other possible contributory factors, our finding that B-lymphocytes entering the islets of NOD mice down-regulate cell surface CD20 expression may partly explain why the tested rituximab mono-therapy did not represent a robust T1D intervention. It is currently only possible to consider initiation of possible T1D interventions in humans that have already developed markers of ongoing aggressive pathogenic autoimmunity such as the presence of insulin autoantibodies (IAA). Thus, the central goal of this proposal is to identify other possible B-lymphocyte directed approaches that either independently or synergistically with anti-CD20 provide a more robust late disease stage T1D intervention strategy than those previously assessed. We have found that when initiated in NOD mice at an already IAA positive late stage of disease development transient treatment with a soluble receptor reagent blocking the B-lymphocyte survival factor BAFF efficiently inhibits T1D development. Our new aim 1 is to test the possibility supported by preliminary data that in addition to being purged of those with pathogenic APC activity whether B-lymphocytes remaining present and/or rebounding in NOD mice after transient BAFF blockade convert to a T1D protective immunoregulatory phenotype, and if so how this may mechanistically occur. Possible B-lymphocyte targeting approaches for T1D might also be aided by gaining a greater understanding of the particular autoantigen specific populations that contribute to disease and the genetic basis for their aberrant development. In this regards we have found B-lymphocytes transgenically expressing an immunoglobulin (Ig) molecule recognizing the islet autoantigen peripherin mediate a significantly accelerated rate of T1D development in NOD mice (stock designated NOD-PerIg). This NOD-PerIg stock provides a key resource to test in aim 2 the hypothesis supported by other preliminary data that a hypomorphic Ephb2 allelic variant represents a T1D susceptibility (Idd) gene in NOD mice by enabling the development of pathogenic B-lymphocytes. NOD mice made deficient in the Aicda gene that initiates B-lymphocyte affinity maturation processes are profoundly T1D resistant. Furthermore, treatment with a small molecule termed DIDS also inhibiting B-lymphocyte affinity maturation blocks progression to overt T1D when initiated in already IAA positive NOD mice. Aim 3 will test possibilities supported by preliminary data whether B-lymphocytes remaining present in Aicda deficient or DIDs treated NOD mice inhibit T1D through activity of the immunosuppressive CD73 ecto-enzyme and/or IL-10 production, and also assess if such factors may also be relevant to disease regulation in humans.