Adnesion Receptors of the Insect Immune System

描述（由申请人提供）：在遇到他们 识别为外来物，这是昆虫细胞（血细胞）的主要反应 免疫系统是它们在细胞表面的多层聚集， 在一个被称为封装的过程中的异物。作为发起 当发生聚集和包裹时，血细胞从它们通常的 从非粘附状态到粘附状态并开始表达新的粘附 这些蛋白质协调了包裹过程。许多病原体和 然而，寄生虫能够绕过昆虫的这种宿主防御， 阻止或抑制粘附受体的表达。 尽管已知多种粘附受体参与了细胞的粘附， 免疫系统中细胞的相互作用，没有类似的受体 参与调节包囊形成的基因。建立 粘附受体在昆虫免疫应答中的作用，本研究将 通过几条路线使用大型的，研究充分的蛾Manduca sexta。 三组与浆细胞粘附和包囊有关的蛋白质 将被调查。(1)颗粒细胞特异性蛋白的功能 将测试浆细胞粘附中的腔隙蛋白。这种多结构域蛋白 存在于外来表面和膜之间的界面处的胶囊中。 粘附的浆细胞实验将测试血小板反应蛋白 在浆细胞粘附中的腔隙蛋白结构域。(2)昆虫细胞的功能 来自免疫球蛋白超家族的粘附蛋白在血细胞包裹中的作用 将被调查。代表假定粘附剂的重组蛋白质 也具有亚氨基菊糖蛋白样结构域的三种表面蛋白的结构域 因为针对这些表面蛋白产生的抗体将被测定其 对血细胞聚集和包囊的影响。(3)两个浆细胞 在包封中起作用的完整膜蛋白将被 表征了针对这些表面蛋白的单克隆抗体破坏了 浆细胞聚集。和封装。这些单克隆抗体是 用于亲和纯化用于部分测序的蛋白质。信息 现在可获得来自每种蛋白质的几种肽的部分序列， 将产生用于筛选血细胞cDNA文库的探针，并获得 他们的完整序列，这应该揭示这些额外的功能， 粘附受体 了解昆虫免疫反应的分子基础， 有助于了解病原体在昆虫血液中的命运 人类疾病的传播媒介。

DESCRIPTION (provided by the applicant): Upon encountering objects that they recognize as foreign, a primary response of the cells (hemocytes) of the insect immune system is their aggregation in multiple layers on the surfaces of the foreign object in a process known as encapsulation. As the initiation of aggregation and encapsulation occurs, hemocytes switch from their usual nonadherent state to an adherent state and begin expressing new adhesion proteins that orchestrate the encapsulation process. Many pathogens and parasites, however, are able to circumvent this host defense of insects by either preventing or suppressing the expression of adhesion receptors. Although a great variety of adhesion receptors are known to be involved in the interactions of cells in the mammnalian immune system, no comparable receptors involved in regulating encapsulation are yet known for insects. To establish the role of adhesion receptors in the insect immune response, this study will proceed by several routes using the large, well-studied moth Manduca sexta. Three groups of proteins implicated in plasmatocyte adhesion and encapsulation will be investigated. (1) The function of the granular cell-specific protein lacunin in adhesion of plasmatocytes will be tested. This multidomain protein is present in capsules at the interface between the foreign surface and the adherent plasmatocytes. Experiments will test the role of the thrombospondin domains of lacunin in plasmatocyte adhesion. (2) The function of insect cell adhesion proteins from the immunoglobulin superfamily in hemocyte encapsulation will be investigated. Recombinant proteins representing the putative adhesive domains of three surface proteins having iminunoglobulin-like domains as well as antibodies generated to these surface proteins will be assayed for their effects on aggregation and encapsulation of hemocytes. (3) Two plasmatocyte integral membrane proteins, which function in encapsulation, will be characterized. Monoclonal antibodies against these surface proteins disrupt plasmatocyte aggregation. and encapsulation. These monoclonal antibodies were used to affinity purify the proteins for partial sequencing. With information now available on the partial sequences of several peptides from each protein, probes will be generated for screening of a hemocyte cDNA library and obtaining their complete sequences, which should reveal additional features of these adhesion receptors. Understanding the molecular underpinnings of the insect immune response will clearly help in understanding the fate of pathogens in the blood of insect vectors of human diseases.