The eae gene of enteropathogenic Escherichia coli encodes a 94-kilodalton membrane protein, the expression of which is influenced by the EAF plasmid

Abstract

The production of a characteristic intestinal histopathology called attaching and effacing (A/E) lesions by enteropathogenic Escherichia coli (EPEC) is a major characteristic of EPEC pathogenesis. We previously identified a chromosomal gene (eae) of EPEC necessary for the production of A/E lesions on human tissue culture cells. Using antiserum raised to an Eae- PhoA fusion protein, we found that the eae gene encodes a 94-kDa membrane protein. This antiserum recognized a 94-kDa membrane protein in parent strain E2348/69 and a protein of similar size in E. coli HB101 carrying eae on a plasmid but did not recognize any proteins in E. coli HB101 carrying a plasmid with an internal deletion in the eae gene. Antigenically related proteins of ca. 94 kDa were detected in a collection of EPEC strains representing seven EPEC serogroups and in two EHEC strains of serotype O26:H11. Volunteer sera drawn 28 days after but not before ingestion of strain E2348/69 recognized the 94-kDa Eae protein as well as a 128-kDa Eae- PhoA fusion protein, suggesting that the Eae protein is likely to be a previously reported 94-kDa protein shown to be immunogenic in volunteers. The amount of detectable Eae protein was increased in the presence of a high- molecular-weight plasmid which is associated with the ability to produce localized adherence to tissue culture cells. These data suggest that the virulence plasmid of EPEC strain E2348/69 may have a regulatory role in the production of A/E activity.