Human Islet Antigen Discovery and Imaging

描述(由申请人提供)：我们研究的总体目标是开发适合于胰岛移植或1型糖尿病背景下的人胰岛成像的试剂。在这个胰岛标记发现计划中，我们将大量借鉴肿瘤免疫学，使用基因表达分析、生物信息学、血清学和蛋白质化学的抗原挖掘技术。在特定的目标一，我们结合这些方法来表征人类胰岛组织的细胞表面。我们将使用两种收敛策略来确定候选的胰岛特异性标记。在A部分，将使用转录图谱来获得人类胰岛、外分泌胰腺和肝组织的基因表达图谱。这些信息将允许我们生成候选标记的维恩图，这些标记由人类胰岛表达，而不是由胰腺的外分泌成分表达，也不是由肝脏表达。另一种基于核酸的方法将被用来验证由转录图谱确定的候选标记的组织特异性和分布。在B部分，我们将使用重组cDNA表达文库的血清学分析(SEREX)技术(也称为噬菌体表达文库的抗体筛选)来鉴定可能用于成像的胰岛细胞表面相关分子。将以一种独特的方式创建表达文库，以移除在胰岛和胰腺(或肝脏)外分泌成分中表达的基因。然后，候选标记蛋白将在细菌系统中表达，以产生特定的抗血清。在特定的目标二，我们将表征识别候选标记的放射性标记抗体的生物分布和摄取动力学。我们将探索和比较基于双硫腙和基于免疫球蛋白(Ig)的放射性标记显像剂在体内检测胰岛组织的能力。在提案的最后阶段，我们将确定这些试剂是否可以用作磁共振成像(MRI)造影剂。在这些临床前研究中，我们将确定移植到免疫缺陷动物模型中的人类胰岛是否可以使用改进的试剂进行检测，以用于非侵入性磁共振(MR)成像研究。我们聚集了一个由细胞生物学家、肿瘤抗原生物学家、移植外科医生和医学物理学家组成的跨学科研究团队，他们的共同目标是开发成像试剂和技术，将胰岛与周围组织区分开来。

DESCRIPTION (provided by applicant): The overall goal of our studies is to develop reagents suitable for imaging human islets in the context of islet transplantation or type 1 diabetes. In this islet marker discovery program, we will borrow heavily from tumor immunology using the antigen mining techniques of gene expression analysis, bioinformatics, serology and protein chemistry. In Specific Aim One, we combine these methods to characterize the cell surface of human islet tissue. We will use two convergent strategies to identify candidate islet specific markers. In part A, transcript profiling will be used to obtain a map of human islet, exocrine pancreas and liver tissue gene expression. This information will allow us to generate Venn diagrams of candidate markers that are expressed by human islets and not by the exocrine component of the pancreas and not by the liver. Alternate nucleic acid based methods will be used to validate the tissue specificity and distribution of candidate markers determined by transcript profiling. In part B, we will use an adaptation of the serological analysis of recombinant cDNA expression libraries (SEREX) technique (a.k.a., antibody screening of phage expression libraries) to identify islet cell surface associated molecules that may be useful in imaging. Expression libraries will be created in a unique manner as to remove genes that are expressed both in islets and in the exocrine component of the pancreas (or liver). Candidate marker proteins will then be expressed in bacterial systems for the generation of specific antisera. In Specific Aim Two, we will characterize the biodistribution and uptake kinetics of radiolabeled antibodies recognizing candidate markers. We will explore and compare the ability of Dithizone based and immunoglobulin (Ig) based radiolabel imaging reagents to detect islet tissue in vivo. In the last phase of the proposal we shall determine whether these reagents can be used as magnetic resonance imaging (MRI) contrast reagents. In these preclinical studies we will determine whether human islets, transplanted into an immunodeficient animal model, can be detected using reagents modified for use in non-invasive magnetic resonance (MR) imaging studies. We have drawn together an interdisciplinary research team of cell biologists, tumor antigen biologists, transplant surgeons and medical physicists with a common goal of developing of imaging reagents and techniques that distinguish islets from their surrounding tissue.