Escherichia coli antibody-secreting cells in the human intestine.

Mononuclear cells were isolated from the mucosa and submucosa of small intestine and colon of 22 subjects with localized, anatomically remote disease and four subjects with Crohn's disease (nine specimens) by sequential treatment with EDTA and collagenase. The effects of isolation techniques on cell yields and viability were examined. Secretion of specific IgA, IgM and IgG antibodies to common faecal Escherichia coli strains by individual mononuclear cells was studied using a haemolytic plaque assay. A majority of specific antibody secreting cells secreted IgA antibody. This response was greatest and most consistent in the distal colon but extended from stomach to rectum. There was no evidence of a primary defect in IgA antibody response in the few subjects with Crohn's disease available for study.