Use of human embryo lung fibroblasts to detect a heat labile toxin of Escherichia coli from children.

In order to detect the heat labile toxin of Escherichia coli human embryo lung fibroblast cells were seeded with whole cell lysate preparations of the organism to be tested. Positive results consisted of growth inhibition and cytopathic change which were easily seen. Heat-labile toxin was produced by strains belonging to the conventional epidemic serotypes of E. coli (EEC) and by non-EEC strains. Toxin-producing organisms were detected in 20% of healthy children examined. The method is suitable for use in the diagnostic laboratory and is easily adapted to a microtitre plate system suitable for screening purposes.