The adjuvant effect of Vibrio cholerae and Escherichia coli heat-labile enterotoxins is linked to their ADP-ribosyltransferase activity.
Mucosal adjuvanticity and immunogenicity of LTR72, a novel mutant of Escherichia coli heat-labile enterotoxin with partial knockout of ADP-ribosyltransferase activity.
The enzymes, known as ADP-ribosyltransferases, modify cellular proteins and in the process cause the symptoms of the diseases.
Investigators had assumed that all forms of these enzymes cause disease, but they have now found a bacterium, Vibrio fischeri, that secretes ADP-ribosyltransferases and is nonpathogenic.