Non-antibody components in human milk inhibit Escherichia coli heat labile enterotoxin measured by an enzyme-linked immunosorbent assay.

Milk from 11 Norwegian women was fractionated by ammonium sulphate precipitation and column chromatography. The milk samples inhibited the binding of heat labile E. coli enterotoxin to antibodies coated on microtiter plates in an enzyme-linked immunosorbent assay. Inhibiting activity was not detected when the toxin was measured in an adrenal cell assay. The inhibiting activity was of a non-immunoglobulin nature with an apparent molecular weight of greater than 400 000 in gel filtration experiments.