STUDIES OF THE BIOREGULATORY ASPECTS OF THE RETINAL PIGMENT EPITHELIAL CELL

视网膜色素上皮(RPE)细胞在 维持神经的结构和生理完整性 视网膜。我们已经在体外分离和培养了RPE细胞，并 开发了针对人RPE细胞的单抗。这个 RPE表位是一种67 kDa的蛋白质，与 微体细胞膜。已分离到一个编码一个基因的cDNA克隆 与数据库中任何其他序列都不匹配的蛋白质。我们 正在使用这些技术和试剂来评估分子， RPE细胞的生化和生物学特性。 细胞因子，如干扰素(干扰素)-γ和白介素2(IL-2)， 是一组特殊的荷尔蒙样蛋白，它们对 对细胞发育的影响和对多种细胞的影响 功能。这个项目集中研究了 细胞因子与免疫系统的细胞相互作用 眼部微环境。我们已经证明，干扰素-γ和IL-2是 发炎眼内发现与T细胞浸润有关 和主要组织相容性复合体(MHC)II类抗原的表达 在浸润性细胞和RPE细胞上。此外，干扰素-γ 活化的RPE细胞可以处理抗原并将其呈递给辅助T细胞 淋巴细胞。这些研究表明，细胞因子介导的激活 RPE细胞的数量可能是眼睛免疫的基本成分 RPE细胞移植的重要方面。 IL-1、肿瘤坏死因子(肿瘤坏死因子)和干扰素-γ是有效的 促炎症细胞因子也可以激活RPE细胞产生 IL-6和细胞间黏附分子-1(ICAM-1)的mRNA和蛋白。 此外，这些细胞因子还可诱导RPE细胞产生一氧化氮(NO)。不是的 细胞毒性，并可能在炎症性和 神经退行性疾病。细胞因子经常可以与 在可以改变的协同或对抗过程中彼此 细胞功能。对这些相互作用的理解可能会提供 改变细胞反应的基本原理。使用这种方法，我们发现 促炎症细胞因子(IL-1、肿瘤坏死因子、干扰素-γ)诱导NO 转化生长因子可抑制视网膜色素上皮细胞 (转化生长因子)--贝塔。逆转录酶-聚合酶链式反应 (RT-PCR)，我们发现转化生长因子-β抑制细胞因子介导的诱导 RPE细胞中NO合成酶基因的表达。 繁殖和移植RPE细胞的研究也在进行中 各种各样的动物。我们已经建立了移植物排斥反应模型 将人RPE细胞移植到大鼠视网膜。这些研究 证明了免疫的细胞和体液方面 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.