Molecular aspects of immunoglobulin A1 degradation by oral streptococci
Molecular aspects of immunoglobulin A1 degradation by oral streptococci
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DOI：
10.1128/iai.58.5.1186-1194.1990
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发表时间：
1990-05
影响因子：
3.1
通讯作者：
J. Reinholdt;Milan Tomana;S. B. Mortensen;M. Kilian
中科院分区：
文献类型：
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作者：
J. Reinholdt;Milan Tomana;S. B. Mortensen;M. Kilian
使用一组143株根据一种新的口腔草绿色型链球菌分类系统，我们重新检查口腔链球菌攻击人免疫球蛋白A1（IgA 1）分子与IgA 1蛋白酶或glycoproteinases的能力。IgA 1蛋白酶的产生是属于血链球菌和口腔链球菌的所有菌株的独有特性（以前称为S.缓症链球菌（Streptococcus mitis）生物变型1的一些菌株。这些都是牙菌斑形成的主要引发剂。在S. oralis和产蛋白酶的S.缓症菌生物变种1.神经氨酸酶和β-半乳糖苷酶被确定为这些类群的生物体中的胞外酶。通过酶中和抗血清检测，在S. sanguisbiovars1 ~ 3、S. sanguis biovar 4，S. oralis和S.分别为。发现链球菌伊加蛋白酶对IgA 1分子的裂解受其糖基化状态的影响。用细菌（包括链球菌）神经氨酸酶治疗IgA 1增加了对蛋白酶的敏感性，表明链球菌IgA 1蛋白酶和神经氨酸酶的协同活性。相反，在用内切-α-N乙酰氨基半乳糖苷酶对铰链区进行广泛的去糖基化后，观察到易感性降低。伊加抗体的效应子功能取决于含碳水化合物的Fc部分。因此，观察到口腔链球菌不仅可以切割α 1链，而且还可以切割IgA 1分子的碳水化合物部分，这表明逃避分泌免疫机制的能力可能有助于这些细菌在口腔中的成功建立。
Using a panel of 143 strains classified according to a novel taxonomic system for oral viridans-type streptococci, we reexamined the ability of oral streptococci to attack human immunoglobulin A1 (IgA1) molecules with IgA1 protease or glycosidases. IgA1 protease production was an exclusive property of all strains belonging to Streptococcus sanguis and Streptococcus oralis (previously S. mitior) and of some strains of Streptococcus mitis biovar 1. These are all dominant initiators of dental plaque formation. Degradation of the carbohydrate moiety of IgA1 molecules accompanied IgA1 protease activity in S. oralis and protease-producing strains of S. mitis biovar 1. Neuraminidase and beta-galactosidase were identified as extracellular enzymes in organisms of these taxa. By examination with enzyme-neutralizing antisera, four distinct IgA1 proteases were detected in S. sanguis biovars 1 to 3, S. sanguis biovar 4, S. oralis, and strains of S. mitis, respectively. The cleavage of IgA1 molecules by streptococcal IgA proteases was found to be influenced by their state of glycosylation. Treatment of IgA1 with bacterial (including streptococcal) neuraminidase increased susceptibility to protease, suggesting a cooperative activity of streptococcal IgA1 protease and neuraminidase. In contrast, a decrease in susceptibility was observed after extensive deglycosylation of the hinge region with endo-alpha-N acetylgalactosaminidase. The effector functions of IgA antibodies depend on the carbohydrate-containing Fc portion. Hence, the observation that oral streptococci may cleave not only the alpha 1 chains but also the carbohydrate moiety of IgA1 molecules suggests that the ability to evade secretory immune mechanisms may contribute to the successful establishment of these bacteria in the oral cavity.