Isolation and characterization of a novel molecule in Salmonella enteritidis that related to binding and infection of the bacterium to human epithelial cell lines, T-84 and Caco-2.

沙门氏菌可引起一系列人类疾病，如胃肠炎、伤寒和菌血症。感染的最初步骤是黏附在肠道细胞的粘膜表面，然后侵袭上皮细胞，然后侵入身体。在这项研究中，我们开发了一种中和抗体来抑制肠炎沙门氏菌与培养的人上皮细胞株T-84和Caco-2的结合。我们还鉴定了这种中和抗体识别的肠炎沙门氏菌的主要抗原之一，鞭毛蛋白。我们纯化了抗鞭毛抗体，并检测了该抗体是否能阻断肠炎沙门氏菌对上皮细胞的感染。它强烈地抑制了肠炎沙门氏菌与细胞的结合，随后被细胞摄取，以及细胞内的生长。然而，在允许肠炎沙门氏菌在细胞内生长的细胞的长期培养过程中，它并不影响这些细胞产生IL-8。这些结果表明，鞭毛沙门氏菌在细菌与人类花药细胞的结合和内化中起着重要作用，但它可能不是触发这些感染细胞产生IL-8的原因。

Salmonella species cause a series of human diseases, such as gastroenteritis, typhoid fever and bacteremia. The initial step of the infection starts with adherence to mucosal surfaces of the intestinal cells, followed by invasion to the epithelial cells and then to the body. In this study, we developed a neutralizing antibody to inhibit the binding of Salmonella Enteritidis to the cultured human epithelial cell lines, T-84 and Caco-2. We also identified one of the major antigens of Salmonella Enteritidis recognized by this neutralizing antibody, as flagellin. We purified anti-flagella antibody and examined whether this antibody block the infection of Salmonella Enteritidis to the epitherial cells. It strongly inhibited binding to the cells, subsequent uptake by the cells, and intracellular growth of Salmonella Enteritidis. However, it did not affect the production of IL-8 from these cells during the prolonged culture of the cells which permitted the intracellular growth of Salmonella Enteritidis. These results suggest that Salmonella flagella plays an important role on the binding and internalization of the bacteria to the human eptherial cells but it might not be responsible for triggering production of IL-8 from these infected cells.