COMPLEMENT DEFICIENCY STATES
COMPLEMENT DEFICIENCY STATES
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补充缺陷状态
DOI：
10.1097/00005792-197801000-00001
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发表时间：
1978
期刊：
影响因子：
1.6
通讯作者：
V. Agnello
中科院分区：
文献类型：
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作者：
V. Agnello
由美国国立卫生研究院资助。5 RO1 AM 16984和5 KO4 A 170968 tigen将修复并激活C1q。活化不导致裂解。然而，它的固定确实激活了C1r中的酶活性，该酶活性裂解C1s，从而产生补体系统中的第一种主要酶，CT或通常称为C1酯酶。这种酶的血清抑制剂存在，C1酯酶抑制剂。然后CI切割C4和C2，其主要切割产物形成具有新酶活性的双分子复合物CE 2a。这是经典的C3转化酶，其能够将C3裂解成小片段C3a和较大片段C3b。C3b与C4b2a复合物的连接导致经典途径中最后一种酶C4b2a3b的形成，其能够结合和切割C5（73，85）。补体激活的另一条途径是1954年由Pillemer和他的同事首次描述的，它是一种在没有抗原抗体复合物存在的情况下激活补体的机制。酵母聚糖是一种酵母细胞壁多糖，被发现可激活补体C3和末端成分，而不利用C1、C4或C2（96）。Pillemer认为，这一途径可能代表了未免疫宿主对外来生物的天然防御系统。在过去的几年里，对这一途径的深入研究证实了他最初的许多观察和印象。替代途径似乎是酵母和细菌壁成分以及可能的其他物质在不存在特异性抗体的情况下激活补体系统的机制（47，51，69，84）。已经分离和鉴定了该途径的许多组分（表1），包括备解素。该途径尚未完全描绘，为了讨论的目的，提供了一个简化的方案（图1）。激活物质可以是酵母聚糖、各种多糖（包括细菌脂多糖、聚集的伊加或聚集的IgE），与称为起始因子（IF）的血清蛋白相互作用，该因子似乎与C3NeF或肾炎因子相同（77，125）。该蛋白最初在系膜毛细血管性肾小球肾炎患者的血清中发现，可降低血清C3水平（123）。在该复合物与因子B、因子D、C3和C3 B相互作用后，形成C3转化酶C3 b B。这种酶与经典的C3转化酶一样，
Supported by National Institutes of Health Grant Nos. 5 RO1 AM 16984 and 5 KO4 A 170968 tigen, will fix and activate C1q. The activation does not result in cleavage. However, its fixation does activate an enzymatic activity in C1r that cleaves C1s and thereby generates the first major enzyme in the complement system, CT or C1 esterase as it is commonly called. A serum inhibitor for this enzyme exists, the C1 esterase inhibitor. CI then cleaves C4 and C2 whose major cleavage products form a bimolecular complex, CE2a which has a new enzyme activity. This is the classical C3 convertase, which is capable of splitting C3 into a small fragment C3a and a larger fragment C3b. The attachment of C3b to the C4b2a complex leads to the formation of the last enzyme in the classical pathway, C4b2a3b, which is capable of binding and cleaving, C5 (73, 85). Following the binding of C5b, the remainder of the terminal components of the complement sequence are assembled without enzy-matic activation.The alternate pathway of complement activation was first described in 1954 by Pillemer and his colleagues as a mechanism whereby complement could be activated without the presence of antigenantibody complexes. Zymosan, a yeast cell wall polysaccharide was found to activate C3 and the terminal components of complement without utilization of C1, C4, or C2 (96). Pillemer thought that this pathway may represent a natural defense system against foreign organisms in the unimmunized host. In the last few years intensive renewed study of this pathway has confirmed many of his original observations and impressions. The alternate pathway does appear to be a mechanism for activation of the complement system by yeast and bacteriał wall components as well as possibly other substances without the presence of specific antibody (47, 51, 69, 84). A number of components of this pathway have been isolated and identified (Table l), including properdin. The pathway has not as yet been completely delineated and for the purpose of this discussion a simplified scheme (Fig. 1) is pre-sented. The activating substance, which may be zymosan, a variety of polysaccharides including bacterial lipopolysaccharides, aggregated IgA or ag-gregated IgE, interact with a serum protein called the initiating factor (IF), which appears to be identical with C3NeF or nephritic factor (77, 125). This protein was originally identified in the serum of patients with mesangiocapillary glomerulonephritis and lowered serum levels of C3 (123). Following the interaction of this complex with Factor B, Factor D, C3 and C3b, a C3 convertase is formed, C3bB. This enzyme, like the classical C3 convertase, can split