IN VIVO ROLE OF CRP IN TRANSGENIC MICE

C-反应蛋白（CRP）是一种肝源性急性时相蛋白 其血浆浓度响应于多种 炎症刺激。 CRP是一种结合蛋白， 已发现其配体能够激活补体， 影响吞噬细胞的功能。 CRP还含有簇蛋白样 C反应蛋白的肽和蛋白水解片段可以刺激炎症细胞。 这些性质沿着蛋白质的进化保守性（ 甚至在一些无脊椎动物中也有发现），被解释为表明 CRP的功能是调节炎症反应。 与大多数脊椎动物不同，老鼠不合成一种 显著量的CRP响应于炎症刺激。 我们有 利用这种进化上的奇特性， 能够表达兔CRP，以确定 体内CRP。 这些动物将被用来评估 兔CRP在三种建立的小鼠炎症模型中。 我们将：1） 初步表征CRP在我们建立的转基因小鼠中的性质， 鼠标线。 2)确定的病理生理和形态学影响， 转基因CRP对内毒素休克、抗原诱导的急性关节炎和 乳酸杆菌在这些动物中诱导心脏炎。 3)体内试验 CRP的磷酸胆碱（PC）结合域的重要性，因为PC是 一种普遍存在的底物，CRP与之强烈结合。 该域名将 通过兔CRP基因的定点突变改变， 证实这些突变体不能结合PC（表达后 在转染的细胞系中），将用于产生额外的 转基因小鼠 改变PC结合结构域对细胞凋亡的影响 将在1）中概述的模型中测试CRP的功能特性 （2）以上。

C-reactive protein (CRP) is an acute phase protein of hepatic origin in man whose plasma concentration increases markedly in response to a wide variety of inflammatory stimuli. CRP is a binding protein which, when bound to one of its ligands, has been found capable of activating complement, and affecting the function of phagocytic cells. CRP also contains tuftsin-like peptides and proteolytic fragments of CRP can stimulate inflammatory cells. These properties along with evolutionary conservation of the protein (which is even found in some invertebrates), have been interpreted as indicating that CRP functions to modulate the inflammatory response. The mouse, in contrast to most vertebrates, does not synthesize a significant quantity of CRP in response to inflammatory stimuli. We have taken advantage of this evolutionary oddity and produced transgenic mice capable of expressing rabbit CRP in order to define the functional role of CRP in vivo. These animals will be employed to assess the effects of rabbit CRP in three established mouse models of inflammation. We will: 1) Initially characterize the properties of CRP in our established transgenic mouse lines. 2) Determine the pathophysiologic and morphologic effects of transgenic CRP on endotoxic shock, antigen-induced acute arthritis and Lactobacillus induced carditis in these animals. 3) Test the in vivo importance of the phosphorylcholine (PC) binding domain of CRP since PC is a ubiquitous substrate to which CRP binds avidly. This domain will be altered by site directed mutagenesis of the rabbit CRP gene and, after confirmation that these mutants are unable to bind PC (following expression in transfected cell lines), will be employed to produce additional transgenic mice. The effects of altering the PC binding domain on the functional properties of CRP will be tested in the models outlined in 1) and 2) above.