A LYMPHOBLAST MODEL FOR DISEASES OF METABOLISM

重症联合免疫缺陷病由于遗传性缺乏 腺苷脱氨酶（ADA）是一个焦点，用于评估创新的 用聚乙烯替代酶的治疗方法 乙二醇修饰的牛ADA（PEG-ADA）和体细胞基因 补充。 本建议书的研究目标是 了解遗传、生化和免疫因素， 限制或确定患者对PEG-ADA的反应， 研究可允许PEG-酶更广泛应用策略 治疗其他先天性代谢缺陷。 我们的具体目标是：（1） 描述PEG-ADA患者ADA等位基因的突变，并研究 这些突变等位基因在体外和适当细胞中的表达 为了确定那些允许足够的残留ADA活性的药物， 在酶替代期间允许免疫重建; 2） 研究某些突变型ADA选择性表达的基础， 一些患者的T细胞;和3）对一些患者的牛ADA的cDNA进行测序， 为了表征抑制性抗体与ADA的结合位点 在接受PEG-ADA治疗的患者中发生;以及 试图用定向的免疫抑制剂组合“中和”这些表位， 诱变和PEG修饰。

Severe combined immunodeficiehcy disease due to inherited deficiency of adenosine deaminase (ADA) is a focal point for evaluation of innovative approaches to therapy by enzyme replacement with polyethylene glycol-modified bovine ADA (PEG-ADA) and by somatic cell gene supplementation. The research objectives of this proposal are aimed at understanding the genetic, biochemical and immunologic factors that limit or determine the response of patients to PEG-ADA, and to investigate a strategy that may permit wider application of PEG-enzyme therapy for other inborn errors of metabolism. Our specific aims are 1) To characterize mutations in ADA alleles of PEG-ADA patients and study the expression of these mutant alleles in vitro and in appropriate cells in order to identify those that allow sufficient residual ADA activity to permit immune reconstitution during enzyme replacement; 2) to investigate the basis for selective expression of certain mutant ADAs in T cells of some patients; and 3) to sequence the cDNA for bovine ADA in order to characterize the binding site of inhibitory antibodies to ADA that develop in patients undergoing treatment with PEG-ADA; and to attempt to 'neutralize' these epitopes with a combination of directed mutagenesis and PEG-modification.