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）发挥作用， 在保护昆虫免受入侵生物的侵害方面起着重要作用;在很大程度上， 一种确定给定物种是否是给定物种的相容宿主的措施。 寄生虫后生动物寄生虫和其他大型入侵者通常被杀死 通过包囊;某些种类的血细胞附着在 并散布在外来目标的表面，形成一个 细胞的多层鞘。尽管这一点至关重要， 防御反应无脊椎动物，具体的细胞和分子 协调胶囊形成的机制几乎完全未知。在 这项研究我们提出了表征细胞和生化因素， 介导鳞翅目昆虫拟夜蛾（Pseudoplusia）的包囊形成 包括。我们的背景数据表明，封装外国 包涵体变形杆菌的靶点涉及血细胞的特定亚群。一 < 3 kDa肽促进某些血细胞从非粘附性细胞转变为非粘附性细胞。 至粘附状态，而胶囊期间细胞间粘附较强 形成涉及Arg-Gly-Asp（RGD）依赖性粘附机制。 基于这些观察，我们提出，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。具体 这项建议的目标是：血细胞特征 参与包囊形成的亚群，2.描述RGD- 介导细胞粘附的结合蛋白，3.识别<3 kDa因子 促进血细胞扩散的基因，以及4）分离其他参与 封装将使用以下样本组监测血细胞反应： 针对特定细胞群的单克隆抗体。表征 介导包囊形成的因素将涉及标准的生物化学和 与特定生物测定相关的分子方法。封装响应 在无脊椎动物类群中是保守的， 介导细胞粘附的重要机制。因此，我们从这件事中学到的 研究将与许多分类群有关，并将提供重要比较 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.