B-lymphocyte Targeting Therapies for Autoimmune Diabetes

项目总结/摘要 在NOD小鼠模型和可能的人类中，B淋巴细胞在1型糖尿病（T1 D）中起关键作用。 通过作为抗原呈递细胞（APC）的子集最有效地支持细胞的扩增， 自身反应性T细胞最终介导胰腺炎细胞破坏。然而，一项临床试验发现，B- 淋巴细胞耗竭CD 20特异性利妥昔单抗抗体作为可能的T1 D仅部分有效 干预虽然不排除其他可能的促成因素，但我们的发现是，B淋巴细胞进入 NOD小鼠的胰岛下调细胞表面CD 20的表达可能部分解释了为什么受试的 利妥昔单抗单一疗法并不代表一种强有力的T1 D干预。目前只能考虑 在已经发展出持续侵袭性疾病标志物的人类中启动可能的T1 D干预措施 致病性自身免疫，如胰岛素自身抗体（IAA）的存在。因此，本项目的中心目标 建议是确定其他可能的B淋巴细胞定向方法， 与抗CD 20协同提供了比那些更稳健晚期疾病阶段T1 D干预策略 以前评估过。我们已经发现，当在NOD小鼠中开始时，在已经是IAA阳性的晚期阶段， 用可溶性受体试剂阻断B淋巴细胞存活的疾病发展短暂治疗 因子BAFF有效地抑制T1 D发展。我们的新目标1是测试支持的可能性， 初步数据表明，除了清除那些具有致病性APC活性的B淋巴细胞外， 在NOD小鼠中短暂BAFF阻断后剩余存在和/或反弹转化为T1 D保护性 免疫调节表型，如果是这样，这可能是如何发生的机制。可能的B淋巴细胞靶向 通过更深入地了解特定的自身抗原， 特定的人群，有助于疾病和遗传基础，他们的异常发展。在这 我们已经发现B淋巴细胞转基因表达免疫球蛋白（IG）分子， 胰岛自身抗原外周蛋白介导NOD小鼠中T1 D发展显著加速速率 （库存指定为NOD-PerIg）。这一NOD-PerIg储备为检验目标2中的假设提供了关键资源 得到了其他初步数据的支持，即亚纯型Ephb 2等位基因变体代表T1 D易感性 (Idd)通过使致病性B淋巴细胞的发展，在NOD小鼠中的基因。NOD小鼠 在启动B淋巴细胞亲和力成熟过程的Aicda基因中，T1 D具有很强的抗性。 此外，用称为DIDS的小分子治疗也抑制B淋巴细胞亲和力成熟， 在已经IAA阳性的NOD小鼠中启动时阻断向明显T1 D的进展。目标3将测试可能性 得到了初步数据的支持，无论B淋巴细胞是否仍然存在于Aicda缺陷或DID治疗中 NOD小鼠通过免疫抑制性CD 73胞外酶的活性和/或IL-10的产生来抑制T1 D， 并评估这些因素是否也可能与人类疾病调节有关。

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.