INHIBITION OF ENTEROPATHOGENIC ESCHERICHIA-COLI ADHESION TO HELA-CELLS BY SERUM OF INFANTS WITH DIARRHEA AND BY CORD SERUM

We have studied the effect of serum from infants with diarrhea and of cord serum on the localized adherence of enteropathogenic Escherichia coli (EPEC) to HeLa cells. Serum samples from 16 infants with diarrhea due to EPEC of serotypes O55:H6, O111:H-, O111:H2, O119:H6 and O142:H 6 were used. The adherence ability of EPEC strains belonging to seroty pes identical to (homologous) or different from (heterologous) those i solated from the infants' feces was highly inhibited by samples of inf ant serum collected both during the acute phase of the illness and upo n discharge from the hospital. These data confirm the development of a ntibodies against EPEC adhesins and the cross-reaction between differe nt EPEC serotypes. Cord serum inhibited the localized adherence of EPE C strains at different levels according to the serotype of the strain studied. These results suggest that the placental transfer of adhesin- related antibodies does not protect the newborn against EPEC infection s, since half of our patients were less than 30 days old.