Effect of different treatments on the activity of the heat labile enterotoxin of Escherichia coli F11(P155).

A whole cell lysate preparation of the Escherichia coli strain F11(P155) was treated with the following agents: heat (60 degrees C for 30 minutes), pronase, lipase, amylase, formalin (0.1%), sodium lauryl sulfate (0.05%) and sarkosyl NL30 (0.05%). Except for the amylase treatment, the treated whole cell lysate was inactivated when tested in rabbit gut loops or on Chinese hamster ovary cells. The preparations treated with heat or formalin could be used to produce a neutralizing antiserum or could remove the neutralizing capacity of an anti-F11(P155) serum. Finally, the attempt to demonstrate enterotoxicity with the cytoplasmic membrane of the bacterial cell failed.