Lectins in Insect Immunity

描述：（由申请人提供）：非自我认可是必不可少的 昆虫防御系统的组成部分，以对抗感染。承认 昆虫的非自我主要是通过一套模式识别来完成的 受体，这是一种蛋白质，结合到表面的多糖， 病原体或寄生虫。这种识别启动了多种免疫反应， 反应，包括酚氧化酶原（PPO）的激活和封装。PPO 激活涉及丝氨酸蛋白酶级联反应，导致TC黑色素变性 后生动物和原生动物寄生虫的包囊。在人类的昆虫媒介中 疾病，检测和杀死寄生虫不是非常有效，也许 由于某些识别受体缺乏或不与其他受体相互作用， 分子来刺激足够的保护性反应。知之甚少 由任何模式识别受体介导的识别过程， 昆虫，或引发各种免疫反应的机制 通过识别过程。 凝集素是模式识别受体的主要候选者，因为它们 可以结合到糖蛋白和糖脂表面的末端糖上， 许多病原体。四种新的C型凝集素，免疫凝集素（IMLs），已被 烟草天蛾Manduca sexta身上分离出来的IMLs参与PPO 活化和包封。此外，两个IML-2相关的丝氨酸蛋白酶 同源物（SPH）。sexta是PPO激活所必需的， 酚氧化酶原活化蛋白酶（PAP）。该提案旨在测试 一般假设IML-2与病原体表面的结合或 寄生虫的功能是将酚氧化酶（P0）激活定位于该区域 包围着入侵的有机体这个假设的一部分是IML-2 与寄生虫表面结合参与等离子体复合物的组装 蛋白质，导致PPO的活化，特别是在表面的 入侵者 具体目标是：1.研究IML-2的结合特异性。的结合 将IML-2转化为病原体或寄生虫表面的碳水化合物， 免疫反应。需要进一步的研究来确定碳水化合物 IML-2的结合特异性。2.研究IML-2-SPH启动了一种 蛋白质复合物在PPC活化过程中的表面。血淋巴形成 寄生虫表面的蛋白质复合物可以定位PPO活化， 入侵的部位或入侵寄生虫的表面。实验将 旨在研究IML-2、SPH、PPO、 和PAP。

DESCRIPTION: (provided by the applicant): Non-self recognition is an essential component of the insect defense system to fight infection. Recognition of non-self in insects is mainly accomplished by a set of pattern recognition receptors, which are proteins that bind to polysaccharides in the surface of pathogens or parasites. Such recognition initiates a variety of immune responses, including prophenoloxidase (PPO) activation and encapsulation. PPO activation involves a serine proteinase cascade, leading tc melanotic encapsulation of metazoan and protozoan parasites. In insect vectors of human diseases, detection and killing of parasites are not highly effective, perhaps because certain recognition receptors are lacking or do not interact with othei molecules to stimulate an adequate protective response. Little is known about the recognition process mediated by any pattern recognition receptors in insects, or the mechanisms by which a variety of immune responses are initiated by the recognition process. Lectins are primary candidates as pattern recognition receptors because they can bind to terminal sugars of glycoproteins and glycolipids on the surface of many pathogens. Four novel C-type lectins, immulectins (IMLs), have been isolated from the tobacco hornworm, Manduca sexta. IMLs are involved in PPO activation and encapsulation. Also, two IML-2-associated serine proteinase homologs (SPHs) identified in M. sexta are necessary for PPO activation by prophenoloxidase-activating proteinase (PAP). This proposal aims to test a general hypothesis that binding of IML-2 to the surface of a pathogen or parasite functions to localize phenoloxidase (P0) activation to the area surrounding the invading organism. A part of this hypothesis is that IML-2 bound to a parasite surface participates in assembly of a complex of plasma proteins that results in activation of PPO specifically at the surface of the invader. The specific aims are: 1. Investigate binding specificity of IML-2. The binding of IML-2 to carbohydrates on the surface of pathogens or parasites triggers immune responses. Further research is needed to determine the carbohydrate binding specificity of IML-2. 2. Study IML-2-SPH initiated assembly of a protein complex at a surface during PPC activation. Formation of hemolymph protein complexes on the surface of parasites may localize PPO activation on the site of invasion or on the surface of invading parasites. Experiments will be designed to investigate protein-proteil interactions among IML-2, SPH, PPO, and PAP.