Knutton S, Baldini M M, Kaper J B, McNeish A S
Infect Immun. 1987 Jan;55(1):78-85. doi: 10.1128/iai.55.1.78-85.1987.
Plasmid-encoded adherence factors have been shown to be important for the full expression of enteropathogenic Escherichia coli (EPEC) pathogenicity and for EPEC adhesion to cultured HEp-2 cells. EPEC strain E2348 (O127) shows localized HEp-2 cell adhesion and possesses a 60-megadalton plasmid, pMAR2. When E2348 is cured of pMAR2 it loses the ability to adhere to HEp-2 cells, while nonadherent E. coli K-12 strains P678-54 and HB101 acquire HEp-2 adhesiveness after they gain the plasmid. By electron microscopy, E2348 was seen to adhere to HEp-2 cells in a manner that closely resembled EPEC adhesion to intestinal mucosa; bacteria were intimately attached to projections of the apical HEp-2 cell membrane and caused localized destruction of microvilli. The plasmid-containing K-12 strains, on the other hand, did not show intimate attachment and there was no modification of cell surface architecture. It is concluded that plasmid pMAR2 codes for an adhesin, possibly fimbrial in nature, that promotes HEp-2 adhesion but that other chromosomally encoded factors are required for EPEC to achieve the characteristic mode of intimate cell attachment.
质粒编码的黏附因子已被证明对肠致病性大肠杆菌（EPEC）致病性的充分表达以及EPEC对培养的HEp-2细胞的黏附很重要。EPEC菌株E2348（O127）表现出对HEp-2细胞的局部黏附，并拥有一个60兆道尔顿的质粒pMAR2。当E2348的pMAR2被消除后，它失去了黏附HEp-2细胞的能力，而非黏附性的大肠杆菌K-12菌株P678-54和HB101在获得该质粒后获得了黏附HEp-2细胞的能力。通过电子显微镜观察，发现E2348以一种与EPEC对肠黏膜的黏附非常相似的方式黏附到HEp-2细胞上；细菌紧密附着在顶端HEp-2细胞膜的突起上，并导致微绒毛的局部破坏。另一方面，含有该质粒的K-12菌株没有表现出紧密附着，并且细胞表面结构没有改变。得出的结论是，质粒pMAR2编码一种黏附素，其性质可能是菌毛，它促进了对HEp-2细胞的黏附，但EPEC要实现其特征性的紧密细胞附着模式还需要其他染色体编码的因子。
