Finlay B B, Gumbiner B, Falkow S
Department of Medical Microbiology, Stanford University School of Medicine, California 94305.
J Cell Biol. 1988 Jul;107(1):221-30. doi: 10.1083/jcb.107.1.221.
Many intracellular parasites are capable of penetrating host epithelial barriers. To study this process in more detail we examined the interactions between the pathogenic bacteria Salmonella choleraesuis and polarized epithelial monolayers of Madin-Darby canine kidney (MDCK) cells grown on membrane filters. Association of bacteria with the MDCK cell apical surface was an active event, requiring bacterial RNA and protein synthesis, and was blocked by low temperatures. Salmonella were internalized within a membrane-bound vacuole and exhibited penetration through, but not between MDCK cells. A maximum of 14 Salmonella per MDCK cell crossed the monolayer per hour to the basolateral surface yet the monolayer remained viable and impermeable to Escherichia coli. Apical S. choleraesuis infection resulted in an increase in paracellular permeability but the MDCK intercellular contacts were not significantly disrupted. Basolateral S. choleraesuis infection was inefficient, and only small numbers of S. choleraesuis penetrated to the apical medium.
许多细胞内寄生虫能够穿透宿主上皮屏障。为了更详细地研究这一过程，我们检测了致病性猪霍乱沙门氏菌与生长在膜滤器上的极化上皮单层马-达二氏犬肾（MDCK）细胞之间的相互作用。细菌与MDCK细胞顶端表面的结合是一个活跃的过程，需要细菌RNA和蛋白质合成，并且会被低温阻断。沙门氏菌被内化到一个膜结合的液泡中，并表现出穿过MDCK细胞（而非在细胞之间穿过）的穿透过程。每小时每MDCK细胞最多有14个沙门氏菌穿过单层到达基底外侧表面，但单层细胞仍保持活力且对大肠杆菌不可渗透。顶端感染猪霍乱沙门氏菌导致细胞旁通透性增加，但MDCK细胞间接触未受到显著破坏。基底外侧感染猪霍乱沙门氏菌效率较低，只有少量猪霍乱沙门氏菌穿透到顶端培养基中。
