CELLULAR DEFENSE RESPONSE IN AN INSECT SYSTEM

由于昆虫是人类和动物许多疾病的媒介， 了解寄生虫和它们的昆虫宿主之间的相互作用 一个重要的研究领域。循环血细胞(血细胞)起着 在保护昆虫免受入侵生物体侵袭方面的重要作用； 定义给定物种与给定物种的宿主是否兼容的度量 寄生虫。后生动物寄生虫和其他大型入侵者通常会被杀死 通过封装；某些类别的血细胞附着的过程 并扩散到外来目标的表面，形成一个 多层细胞鞘。尽管这一点的根本重要性 对无脊椎动物的特定细胞和分子防御反应 协调包膜形成的机制几乎完全未知。在……里面 在这项研究中，我们建议表征细胞和生化因素。 介导鳞翅目昆虫褐飞虱的被膜形成 包括。我们的背景数据表明，外源病毒的封装 P.包括涉及特定血细胞亚群的靶细胞。一个 &lt；3 kDa多肽促进某些血细胞从非粘附性改变 胶囊化过程中细胞间黏附较强，处于黏附状态 形成涉及依赖Arg-Gly-Asp(RGD)的黏附机制。 基于这些观察，我们认为胶囊的形成需要一个 具有粘附性的特定类别血细胞的协调反应 由RGD结合蛋白及其胞外配体介导。特定的 这项建议的目标是：1.表征血细胞 参与包膜形成的亚群，2.表征RGD- 介导细胞黏附的结合蛋白，3.鉴定3 kDa因子 这促进了血细胞的传播，并分离了其他与 封装。血细胞反应将使用面板监测 针对特定细胞群体的单抗。特征描述 调节包膜形成的因素将涉及标准的生化和 与特定生物检测相联系的分子方法。封装响应 在无脊椎动物分类群中是保守的，可能从根本上涉及 调节细胞黏附的重要机制。因此，我们在这件事上学到的 研究将与许多分类群相关，并将提供重要的比较 关于调节细胞间通讯的因素的信息。

Since insects are vectors for many diseases of humans and animals, understanding the interactions between parasites and their insect hosts is an important area of study. Circulating blood cells (hemocytes) play an essential role in defending insects against invading organisms; in large measure defining whether a given species is compatible host for a given parasite. Metazoan parasites and other large invaders are usually killed by encapsulation; a process in which certain classes of hemocytes attach and spread across the surface of the foreign target, forming a multilayered sheath of cells. Despite the fundamental importance of this defense response to invertebrates, the specific cellular and molecular mechanisms coordinating capsule formation are almost totally unknown. In this study we propose to characterize the cellular and biochemical factors that mediate capsule formation in the lepidopteran insect Pseudoplusia includens. Our background data indicate that encapsulation of foreign targets by P. includens involves specific subpopulations of hemocytes. A < 3 kDa peptide promotes certain hemocytes to change from an non-adhesive to adhesive state, while strong intercellular adhesion during capsule formation involves an Arg-Gly-Asp (RGD)-dependent adhesion mechanism. Based on these observations we propose that capsule formation requires a coordinated response by specific classes of hemocytes with adhesion mediated by an RGD-binding protein and its extracellular ligand. Specific objectives for this proposal are: 1. characterize the hemocyte subpopulations involved in capsule formation, 2. characterize the RGD- binding protein mediating cell adhesion, 3. identify the <3 kDa factor that promotes hemocyte spreading, and 4) isolate other genes involved in encapsulation. Hemocyte responses will be monitored using panels of monoclonal antibodies to specific cell populations. Characterization of factors mediating capsule formation will involve standard biochemical and molecular approaches linked to specific bioassays. Encapsulation responses are conserved across invertebrate taxa and likely involve fundamentally important mechanisms mediating cell adhesion. Thus, what we learn in this study will be relevant to many taxa and will provide important comparative information on factors regulating cell-cell communication.