Decreased expression of mannose-specific adhesins by Escherichia coli in the colonic microflora of immunoglobulin A-deficient individuals
Decreased expression of mannose-specific adhesins by Escherichia coli in the colonic microflora of immunoglobulin A-deficient individuals
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DOI：
10.1128/iai.64.7.2794-2798.1996
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发表时间：
1996-07-01
影响因子：
3.1
通讯作者：
Wold, AE
中科院分区：
文献类型：
--
作者：
Friman, V;Adlerberth, I;Wold, AE
大多数大肠杆菌分离株都能表达1型菌毛，这种菌毛是甘露糖特有的粘附素。这些粘附素与分泌型免疫球蛋白A(IgA)的寡糖链结合。因此，除了特异的抗体活性外，分泌型IgA还与表达1型菌毛的细菌具有广泛的反应性。如在IgA缺乏症中所见，结肠分泌物中缺乏分泌型IgA，因此可能改变1型菌毛大肠杆菌在这些人的大肠中定植的能力。本研究用DNA-DNA杂交法检测了17例IgA缺陷者和17例年龄匹配的对照组的10株大肠埃希氏菌的fim基因簇，并用豚鼠红细胞血凝试验检测了其1型菌毛的表达。同时分析了I型菌毛介导的黏附对HT-29细胞的作用，IgA缺陷组fim(+)大肠埃希菌的比例低于对照组(74%比94%，P<；0.05)，体外表达1型菌毛的菌株比例(69%比85%，P<；0.05)。来自IgA缺陷个体的分离株对HT-29细胞的甘露糖敏感黏附的中位数低于对照组(每个细胞9个细菌对26个细菌，P<；0.05)。当表达1型菌毛的菌株来自IgA缺陷个体时，它们对HT-29细胞的粘附率低于来自对照个体的菌株(每个细胞15个细菌对27个细菌，P<；0.05)。结果提示，I型菌毛与分泌型IgA的相互作用是这些细菌在大肠内定植的重要原因。
Most Escherichia coli isolates can express type 1 fimbriae,vith mannose-specific adhesins. These adhesins bind to the oligosaccharide chains of secretory immunoglobulin A (IgA). Thus, in addition to specific antibody activity, secretory IgA possesses a broad reactivity with bacteria expressing type 1 fimbriae. The absence of secretory IgA in colonic secretions, as seen in IgA deficiency, might therefore alter the ability of type 1-fimbriated E. coli to colonize the large intestines of these individuals. In the present study, 10 E. coli isolates from each of 17 IgA-deficient and 17 age-matched control individuals were assessed for the carriage of the fim gene cluster by DNA-DNA hybridization and for the expression of type 1 fimbriae by hemagglutination of guinea pig erythrocytes. The contribution of type 1-fimbria-mediated adherence to HT-29 colonic cells was also analyzed, The proportion of fim(+) E. coli isolates was lower in IgA-deficient than in control individuals (74 versus 94%, P < 0.05), as was the proportion of isolates expressing type 1 fimbriae in vitro (69% versus 85%, P < 0.05). The median mannose-sensitive adherence to HT-29 cells was lower for isolates from IgA-deficient individuals than from the controls (9 versus 26 bacteria per cell, P < 0.05). Isolates expressing type 1 fimbriae showed lower adherence to HT-29 cells when they were derived from IgA-deficient individuals than when they were derived from control individuals (15 versus 27 bacteria per cell, P < 0.05). The results suggest that the interaction of type 1 fimbriae with secretory IgA contributes to the large intestinal colonization by these bacteria.