STUDIES OF THE BIOREGULATORY ASPECTS OF THE RETINAL PIGMENT EPITHELIAL CELL

视网膜色素上皮（RPE）细胞在视网膜色素变性中起基础作用。 维持神经系统的结构和生理完整性， 视网膜。我们已经在体外分离和增殖RPE细胞， 开发了针对人RPE细胞的单克隆抗体。的 RPE表位是一种67 kDa的蛋白质，与RPE密切相关。 微粒体膜已经分离出一个cDNA克隆，它编码一个 与数据库中的其他序列不匹配的蛋白质。我们 正在使用这些技术和试剂来评估分子， RPE细胞的生物化学和生物学特性。 细胞因子，如干扰素（IFN）-γ和白细胞介素-2（IL-2）， 是一组特殊的类蛋白质， 对细胞发育和多种细胞的影响 功能协调发展的该项目集中研究了 细胞因子与免疫系统的细胞相互作用， 眼睛的微环境我们已经证明IFN-γ和IL-2是 在发炎的眼睛内发现，与T细胞浸润有关 和主要组织相容性复合体（MHC）II类抗原表达 对浸润细胞和RPE细胞的影响。此外，IFN-γ 激活的RPE细胞可以加工并呈递抗原给辅助性T细胞， 淋巴细胞这些研究表明，马槟榔碱介导的激活 RPE细胞的增殖可能是眼免疫的基本组成部分， RPE细胞移植的重要方面。 IL-1、肿瘤坏死因子（TNF）和IFN-γ具有强效作用 促炎细胞因子也可以激活RPE细胞产生 IL-6和细胞内粘附分子-1（ICAM-1）mRNA和蛋白。 此外，这些细胞因子在RPE细胞中诱导一氧化氮（NO）。no是 细胞毒性，并可能在炎症和 神经退行性疾病细胞因子经常可以与 在协同或拮抗过程中相互作用， 细胞功能对这些相互作用的理解可以提供 改变细胞反应的基本原理。使用这种方法，我们发现 促炎细胞因子（IL-1、TNF、IFN-γ）诱导NO 转化生长因子可抑制RPE细胞的增殖 （TGF）-β。使用逆转录酶-聚合酶链反应 通过RT-PCR检测，我们发现TGF-β抑制了姜黄素介导的诱导， 视网膜色素上皮细胞中NO合成酶mRNA的表达。 研究也在进行中，以在哺乳动物中繁殖和移植RPE细胞。 各种动物。我们建立了一个移植排斥模型， 将人RPE细胞移植到大鼠视网膜中。这些研究 证明了免疫系统的细胞和体液方面 反应被激活以拒绝RPE细胞移植。这些研究 提供了评估细胞因子和免疫反应性的框架， RPE细胞移植

The retinal pigment epithelial (RPE) cell plays a basic role in maintaining the structural and physiological integrity of the neural retina. We have isolated and propagated RPE cells in vitro and have developed monoclonal antibodies directed against human RPE cells. The RPE epitope is a 67 kDa protein that is closely associated with the microsomal membrane. A cDNA clone has been isolated that codes for a protein that does not match any other sequences in the databases. We are using these techniques and reagents to evaluate molecular, biochemical, and bioloical properties of the RPE cells. Cytokines, such as interferon (IFN)-gamma and interleukin-2 (IL-2), are a group of specialized hormone-like proteins that exert profound influences on cellular development and on a variety of cellular functions. This project has concentrated on studying the ways in which cytokines interact with cells of the immune system and with cells in the ocular microenvironment. We have shown that IFN-gamma and IL-2 are found within the inflamed eye in association with T-cell infiltration and major histocompatibility complex (MHC) class II antigen expression on infiltrating cells and on RPE cells. Furthermore, IFN-gamma activated RPE cells can process and present antigens to helper T lymphocytes. These studies indicate that cytokine-mediated activation of RPE cells may be a basic component of ocular immunity and an important aspect of RPE cell transplantation. IL-1, tumor necrosis factor (TNF), and IFN-gamma are potent proinflammatory cytokines that can also activate RPE cells to produce IL-6 and intracellular adhesion molecule-1 (ICAM-1) mRNA and proteins. Moreover, these cytokines induce nitric oxide (NO) in RPE cells. NO is cytotoxic and may play an important role in inflammatory and neurodegenerative diseases. Cytokines frequently can interacte with each other in synergistic or antagonisitc processes that can alter cellular function. An understanding of these interactions may provide rationale to modify cellular responses. Using this approach, we found that proinflammatory cytokine (IL-1, TNF, IFN-gamma) induction of NO in RPE cells can be inhibited by transforming growth factor (TGF)-beta. Using reverse transcriptase-polymerase chain reaction (RT-PCR), we found that TGF-beta inhibits cytokine-mediated induction of NO synthetase mRNA in RPE cells. Studies are also in progress to propagate and transplant RPE cells in various animals. We have established a graft rejection model by transplanting human RPE cells into the rat retina. These studies demonstrate that both cellular and humoral aspects of the immune response are activated to reject RPE cell transplants. These studies provide the framework to evaluate cytokines and immune reactivity in RPE cell transplantation.