de Beer F C, Baltz M L, Munn E A, Feinstein A, Taylor J, Bruton C, Clamp J R, Pepys M B
Immunology. 1982 Jan;45(1):55-70.
C-reactive protein (RP) and serum amyloid P component (SAP) have been identified for the first time in rat serum and isolated by calcium-dependent affinity chromatography. Rat CRP closely resembled human CRP in its amino acid composition, in having five subunits per molecule and in its electron microscopic appearance as a pentameric annular disc. It differed, however, from all other mammalian CRP's characterised hitherto in being a glycoprotein bearing a single complex oligosaccharide on each polypeptide subunit. Furthermore one pair of tis subunits per molecule was linked by a interchain disulphide bridges whereas in other animals the subunits of both CRP and SAP are all non-covalently associated. The serum concentration of CRP in normal healthy laboratory rats and in specific pathogen-free rats was 300-600 micrograms/ml which is much greater than has been described in any other species and exceeds even maximal acute phase levels of CRP in man. Following injections of casein or croton oil, serum CRP levels rose to a maximum of about 900 micrograms/ml. Rat CRP bound to pneumococcal C-polysaccharide (CPS( but, in marked contrast to the behaviour of CRP from man, rabbit and marine teleost fish, it did not precipitate with CPS solutions, agglutinate CPS-coated sheep erythrocytes or initiate complement activation. Rat SAP, like SAP of other species, was a glycoprotein but unlike them it was composed only of a single pentameric disc not two such discs interacting face-to-face. The normal level of SAP in rat serum was 20-50 micrograms/ml, very similar to the levels seen in man, and it did not behave as an acute phase reactant in response to casein or croton-oil injections. In this respect it resembled human SAP but differed from murine SAP which is a major acute phase reactant.
C反应蛋白（CRP）和血清淀粉样P成分（SAP）首次在大鼠血清中被鉴定出来，并通过钙依赖亲和层析法进行分离。大鼠CRP在氨基酸组成、每个分子有五个亚基以及电子显微镜下呈现五聚体环状盘状结构方面与人CRP非常相似。然而，它与迄今已鉴定的所有其他哺乳动物CRP不同，它是一种糖蛋白，每个多肽亚基上带有一个单一的复合寡糖。此外，每个分子的一对亚基通过链间二硫键相连，而在其他动物中，CRP和SAP的亚基都是非共价结合的。正常健康实验大鼠和无特定病原体大鼠血清中CRP的浓度为300 - 600微克/毫升，这比在任何其他物种中所描述的都要高得多，甚至超过了人类CRP的最大急性期水平。注射酪蛋白或巴豆油后，血清CRP水平最高升至约900微克/毫升。大鼠CRP与肺炎球菌C多糖（CPS）结合，但与来自人、兔和海洋硬骨鱼的CRP行为形成显著对比的是，它不会与CPS溶液沉淀、凝集CPS包被的绵羊红细胞或启动补体激活。大鼠SAP与其他物种的SAP一样是一种糖蛋白，但与它们不同的是，它仅由一个单一的五聚体盘组成，而不是两个这样面对面相互作用的盘。大鼠血清中SAP的正常水平为20 - 50微克/毫升，与人中所见水平非常相似，并且在对酪蛋白或巴豆油注射的反应中它不作为急性期反应物。在这方面它类似于人SAP，但不同于作为主要急性期反应物的小鼠SAP。
