Middeldorp J M, Witholt B
Infect Immun. 1981 Jan;31(1):42-51. doi: 10.1128/iai.31.1.42-51.1981.
We have examined the interactions between various radiolabeled membrane fractions obtained from an enterotoxigenic Escherichia coli strain and brush borders isolated from porcine intestinal epithelial cells. Outer membrane fragments containing the K88 attachment factor bound tightly to brush borders, whereas cytoplasmic membrane vesicles did not. Three different types of outer membrane preparations were tested: (i) cellular outer membranes isolated from lysozyme spheroplasts, (ii) medium vesicles or outer membrane fragments released into the medium during growth, and (iii) periplasmic vesicles, or outer membrane fragments which were released from the cells during spheroplast formation and were therefore isolated in the periplasmic fraction. Of these fractions, which were heterogeneous, it was always the outer membrane subfraction which bound tightly to brush borders. This binding, which was K88 dependent, may have some physiological significance in view of the association between outer membrane fragments and enterotoxin. Thus, released outer membrane fragments equipped with attachment factors may function as enterotoxin carriers which increase the efficiency with which enterotoxin can be delivered to intestinal epithelial cells.
我们研究了从产肠毒素大肠杆菌菌株获得的各种放射性标记膜组分与从猪肠上皮细胞分离的刷状缘之间的相互作用。含有K88黏附因子的外膜片段紧密结合于刷状缘，而细胞质膜囊泡则不然。测试了三种不同类型的外膜制剂：（i）从溶菌酶原生质球分离的细胞外膜，（ii）生长期间释放到培养基中的培养基囊泡或外膜片段，以及（iii）周质囊泡，即原生质球形成期间从细胞释放并因此在周质组分中分离的外膜片段。在这些异质组分中，始终是外膜亚组分紧密结合于刷状缘。这种依赖于K88的结合，鉴于外膜片段与肠毒素之间的关联，可能具有一定的生理意义。因此，配备黏附因子的释放外膜片段可能作为肠毒素载体发挥作用，提高肠毒素传递至肠上皮细胞的效率。
