SMALLPOX VIRULENCE AND COMPLEMENT REGULATORY PROTEINS

由于大多数人认为天花是一种生物恐怖武器，已经出现了公共卫生问题 美国人不再有免疫力。痘病毒通过表达补体来破坏补体系统 调节蛋白。在天花、牛痘和外皮病中，这种蛋白质被称为香料(天花抑制剂的意思 补体酶)、VCP(痘苗病毒补体控制蛋白)和EMICE(一种未鉴定的 我们将其标记为“补体酶抑制物”，这是一种类似于皮疹的药物)。这些分泌物 毒力因子通过模仿一个家族的功能谱系下调补体激活 宿主蛋白被称为补体激活调节因子(RCA)。病毒蛋白在结构上也是 与它们的东道主对应物有关。具体目的：1.表征补体抑制谱 与人类的同类相比，它更有调味性。我们将确定主要的补体逃避活动 香料，这将成为中和的目标。这些评估将与本机进行 可溶性蛋白质以及在它通过其肝素结合部位(S)或通过添加 抛锚。2.确定SPICE的补体调控位点。这些实验将利用 RCA蛋白的功能谱(在目标1中定义)和活性位点序列 与SPICE、VCP和EMICE的相应区域同源。这两组数据提供了一个逻辑 突变分析的策略，以定位活性位点。3.描述补体调控的特征 EMICE的活动。这种鼠痘蛋白尚未对其补体抑制(毒性)进行评估。 活动。它与SPICE和VCP的同源性约为90%。我们将首先描述其监管活动的特征 人类和小鼠是互补的。其次，我们将通过感染来评估它在体内作为毒力因子的作用。 敏感和耐药的小鼠品系，其补体调节因子缺失了蜕皮病病毒。这个 拟议的实验将提供与痘病毒感染的发病机制有关的新信息。 人和老鼠。此外，这些结果将作为生产毒性较低的天花疫苗的指南。 并为单抗治疗天花感染寻找病毒靶点。

Public health concems have emerged regarding use of smallpox as a bioterrorist weapon since most Americans are no longer immune. Poxviruses subvert the complement system via the expression of regulatory proteins. In variola, vaccinia and ectromelia, the proteins are called SPICE (for smallpox inhibitor of complement enzymes), VCP (vaccinia virus complement control protein) and EMICE (an uncharactedzed analog in ectromelia that we have labeled "ectromelia inhibitor of complement enzymes"). These secreted virulence factors down-regulate complement activation by mimicking the functional repertoire of a family of host proteins called the Regulators of Complement Activation (RCA). The viral proteins are also structurally related to their host counterparts. Specific Aims: 1. To characterize the complement inhibitory profile of SPICE compared to its human counterparts. We will identify the principal complement-evading activity of SPICE and this will become a target for neutralization. These assessments will take place with the native soluble protein as well as after it attaches to cells via either its heparin-binding site(s) or by addition of an anchor. 2. To determine the complement regulatory sites of SPICE. These experiments will take advantage of the functional profiles (defined in Aim 1) and the sequences of active sites of RCA proteins that are homologous to corresponding regions of SPICE, VCP, and EMICE. These two sets of data provide a logical strategy for a mutational analysis to locate the active sites. 3. To characterize the complement regulatory activity of EMICE. This mousepox protein has not been evaluated for its complement inhibitory (virulence) activity. It is about 90% identical to SPICE and VCP. We will first characterize its regulatory activity for human and mouse complement. Second, we will assess its role in vivo as a virulence factor by infecting sensitive and resistant mouse strains with the ectromelia virus deleted of its complement regulator. The proposed experiments should provide novel information relative to the pathogenesis of poxvirus infections of man and mouse. Additionally, these results will serve as a guide to produce a less toxic small pox vaccine and to identify a viral target for mAb treatment of variola infection.