The agglutinating antibody response in the duodenum of infants with enteropathogenic Escherichia coli gastroenteritis.

The agglutinating antibody response in duodenal fluid and serum was measured serially in 15 infants with enteropathogenic Escherichia coli gastroenteritis. Peak levels of duodenal agglutinins were recorded 8-18 days after the onset of symptoms, and the titres fell within the next 7-14 days. The immunoglobulin (Ig) class of these antibodies was mainly IgA, but IgM antibodies were detected early in the response, especially in the younger infants. Late antibodies showed less cross-reactions with other strains of E. coli than did early antibodies. Serum antibody responses were detected in eight infants, but they correlated poorly with the titres of intestinal antibodies. No rise in serum antibodies was detected in six infants. It is not known whether these differences are host-derived, or whether they are the result of the invasive properties of some of the infecting organisms.