CELLULAR DEFENSE RESPONSE IN AN INSECT SYSTEM

昆虫系统中的细胞防御反应

• 批准号: 2871534
• 负责人: Michael Strand
• 金额: $ 18.66万
• 依托单位: UNIVERSITY OF WISCONSIN-MADISON
• 依托单位国家: 美国
• 财政年份: 1996
• 资助国家: 美国
• 起止时间: 1996-02-01 至 2001-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2871534
• 关键词: Lepidoptera; antisense nucleic acid; blood cells; cell adhesion; cell adhesion molecules; cell capsule; cell population study; cell type; cellular immunity; flow cytometry; gene expression; host organism interaction; immunofluorescence technique; in situ hybridization; laboratory mouse; larva; messenger RNA; molecular cloning; monoclonal antibody; parasitism; peptides; polymerase chain reaction; protein purification; protein sequence; tissue /cell culture

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.

由于昆虫是人类和动物许多疾病的媒介， 了解寄生虫与其昆虫宿主之间的相互作用是 一个重要的研究领域。循环血细胞（血细胞）发挥着 在保护昆虫免受生物体入侵方面发挥重要作用；大的 定义给定物种是否与给定宿主兼容的措施 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 并扩散到异物目标的表面，形成一个 多层细胞鞘。尽管这一点具有根本重要性 对无脊椎动物的防御反应，特定的细胞和分子 协调胶囊形成的机制几乎完全未知。在 这项研究我们建议表征细胞和生化因素 介导鳞翅目昆虫 Pseudoplusia 中荚膜的形成 包括。我们的背景数据表明，国外的封装 P. includens 的目标涉及特定的血细胞亚群。一个 < 3 kDa 肽促进某些血细胞从非粘附性转变为非粘附性 呈粘附状态，胶囊期间细胞间粘附力强 形成涉及精氨酸-甘氨酸-天冬氨酸 (RGD) 依赖的粘附机制。 基于这些观察，我们提出胶囊的形成需要 具有粘附作用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。具体的 该提案的目标是： 1. 表征血细胞 参与胶囊形成的亚群，2. 表征 RGD- 结合蛋白介导细胞粘附，3. 识别 <3 kDa 因子 促进血细胞扩散，4) 分离参与的其他基因 封装。将使用小组监测血细胞反应 针对特定细胞群的单克隆抗体。表征 介导胶囊形成的因素将涉及标准生化和 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，并且可能从根本上涉及 介导细胞粘附的重要机制。因此，我们在此学到的 研究将与许多分类单元相关，并将提供重要的比较 有关调节细胞间通讯的因素的信息。