Anti-LPS Antibodies in Adult and Infant Patients Infected with Enterohemorrhagic Escherichia coli O157

Abstract

The antibodies against LPS of enterohemorrhagic Escherichia coli (EHEC) O157 in sera from patients infected with this organism and sera from healthy control subjects were examined by ELISA to investigate their immune response. Analysing these data, we found some heterogeneity of antibody response between adults and infants.
In healthy adults and children, the cutoff values for IgM antibodies to O157 LPS were calculated as 0.85, 0.40 and for IgG were as 0.57, 0.39 respectively. In patients, the ELISA values of adult were lower and decreased earlier than those of children. Therefore sero diagnosis for EHEC O157 infection for adult patients the timing of blood collection is very important. On the other hand, in some patients the sera of children showed a high level of IgM only 3 days from the onset. This tendency seemed to be related to severity of the disease. This immunological test was proved to be useless for healthy carriers because the antibodies against O157 LPS were not observed in their sera.