Loureiro I, Frankel G, Adu-Bobie J, Dougan G, Trabulsi L R, Carneiro-Sampaio M M
Department of Immunology, University of Sao Paulo, Brazil.
J Pediatr Gastroenterol Nutr. 1998 Aug;27(2):166-71. doi: 10.1097/00005176-199808000-00007.
In Brazil, enteropathogenic Escherichia coli diarrhoea is endemic among infants born into low economic levels, and it is one of the main causes of morbidity and mortality in this group. Binding of enteropathogenic E. coli to the brush border mucosa triggers a cascade of transmembrane and intracellular signals, causing cytoskeletal reorganization and formation of a specific lesion, termed the attaching and effacing lesion. Several enteropathogenic E. coli gene products have been implicated in formation of attaching and effacing lesions. Evaluation of pathogen-specific protective factors shows that breast feeding is effective against enteropathogenic E. coli infection. To investigate the nature of the protection, defatted colostrum and secretory immunoglobulin A obtained from mothers living in Sao Paulo were investigated for the ability to recognise selected enteropathogenic E. coli-associated virulence factors.
Western blot analysis was used to investigate the IgA repertoire in pooled colostrum that is reactive with specific enteropathogenic E. coli proteins. Whole enteropathogenic E. coli bacterial cell extracts, nonpathogenic E. coli strains overexpressing specific virulence factors, and purified polypeptides were used as antigen sources in this study.
Reaction of the colostrum samples in Western blots of whole bacterial cell extracts and selected purified enteropathogenic E. coli proteins showed that they contained a secretory immunoglobulin A reactive with all the virulence-associated proteins studied.
These results suggest that maternal antibodies may protect infants from enteropathogenic E. coli infection by interfering with adherence processes (anti-intimin and anti-bundle-forming pili antibodies) and cell signaling (anti-enteropathogenic Escherichia coli-secreted protein A and B antibodies.
在巴西，肠道致病性大肠杆菌腹泻在经济水平低下家庭出生的婴儿中呈地方性流行，是该群体发病和死亡的主要原因之一。肠道致病性大肠杆菌与刷状缘黏膜结合会引发一系列跨膜和细胞内信号，导致细胞骨架重组并形成一种特定病变，称为紧密黏附损伤。几种肠道致病性大肠杆菌基因产物与紧密黏附损伤的形成有关。对病原体特异性保护因子的评估表明，母乳喂养对肠道致病性大肠杆菌感染有效。为了研究这种保护的本质，对从圣保罗母亲那里获得的脱脂初乳和分泌型免疫球蛋白A识别选定的肠道致病性大肠杆菌相关毒力因子的能力进行了研究。
采用蛋白质印迹分析来研究与特定肠道致病性大肠杆菌蛋白反应的初乳池中的IgA库。在本研究中，将完整的肠道致病性大肠杆菌细菌细胞提取物、过表达特定毒力因子的非致病性大肠杆菌菌株和纯化的多肽用作抗原来源。
初乳样品在完整细菌细胞提取物和选定的纯化肠道致病性大肠杆菌蛋白的蛋白质印迹中的反应表明，它们含有与所有研究的毒力相关蛋白反应的分泌型免疫球蛋白A。
这些结果表明，母体抗体可能通过干扰黏附过程（抗紧密黏附素和抗束状菌毛抗体）和细胞信号传导（抗肠道致病性大肠杆菌分泌蛋白A和B抗体）来保护婴儿免受肠道致病性大肠杆菌感染。
