Defense mechanisms involving Fc-dependent functions of immunoglobulin A and their subversion by bacterial immunoglobulin A proteases.
Defense mechanisms involving Fc-dependent functions of immunoglobulin A and their subversion by bacterial immunoglobulin A proteases.
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防御机制涉及免疫球蛋白 A 的 Fc 依赖性功能及其被细菌免疫球蛋白 A 蛋白酶的颠覆。
DOI：
10.1128/mr.52.2.296-303.1988
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发表时间：
1988
期刊：
影响因子：
--
通讯作者：
Russell,MW
中科院分区：
文献类型：
--
作者：
Kilian,M;Mestecky,J;Russell,MW
免疫球蛋白A （IgA）由包括人类在内的许多物种产生，其数量超过了所有其他免疫球蛋白类别的总和。在人类中，大多数IgA被分泌到大面积（-400 m2）的粘膜表面，成为这些部位体液免疫的主要介质。骨髓中也产生大量的IgA，但其相对于IgG的快速分解代谢导致血清水平低于IgG（26,46）。血清中IgA水平在15年内缓慢成熟，而体外分泌物中的IgA浓度可在短短4至6周内达到成人水平（22）。除了个体发生和细胞起源的差异外，分泌和血清IgA系统在产生的IgA分子特性、两种IgA亚类的分布、抗原特异性和功能方面似乎是独立的（26,47）。血清中的IgA主要以单体形式存在，IgA亚类1 （IgAl）占明显优势。相反，分泌型IgA （S-IgA）以二聚体的形式出现，富含碳水化合物的分泌组分（SC）附着在其上。外分泌液中IgAl和IgA2的分布反映了相应组织中浆细胞的比例，IgA2的比例增加（31,47）。然而，最近的观察表明，不同解剖部位之间存在显著差异。虽然IgA2细胞可能占结肠中S-IgA总量的60%，但鼻腔中的比例
Immunoglobulin A (IgA) is produced by many species, including humans, in quantities exceeding those of all other immunoglobulin classes combined. In humans, most IgA is secreted onto the vast (-400 m2) area of mucosal surfaces, becoming the principal mediator of humoral immunity at these sites. Largeamounts of IgA are also produced in the bone marrow, but its rapid catabolism relative to that of IgG results in serum levels lower than those of IgG (26, 46). While serum levels of IgA mature only slowly over 15 years, the concentrations of IgA in external secretions may reach adult levels in as little as 4 to 6 weeks (22). In additionto differences in ontogeny and cellularorigin, thesecretory and serum IgA systems appear to be independent with respect to the molecular properties of the IgA produced, the distribu-tion of thetwo IgA subclasses, antigen specificities, and functions (26, 47). IgA in serum occurs primarily in monomeric form with a pronounced predominance of IgA subclass 1 (IgAl). In contrast, secretory IgA (S-IgA) occurs as dimeric molecules to which the carbohydrate-rich secretory component (SC) is attached. The distribution of IgAl and IgA2 in external secretions reflects the proportions of plasma cells in the corresponding tissues, with an increase in the proportion of IgA2 (31, 47). However, recent observations indicate that there are notable differences between different anatomical sites. While IgA2 cells may account for up to 60% of total S-IgA in the colon, the proportions in naso-