Selection and characteristics of a Vibrio cholerae mutant lacking the A (ADP-ribosylating) portion of the cholera enterotoxin.

Abstract

After mutagenesis with nitrosoguanidine and selection by immuno-halo techniques, an avirulent mutant, designated Texas Star-SR, which produces no detectable A (active; ADP-ribosylating) region of the cholera enterotoxin (choleragen) but produces the B region (choleragenoid) in amounts similar to the hypertoxinogenic wild-type parent V. cholerae (biotype E1 Tor serotype Ogawa), was isolated. The mutant retains the colonizing ability, motility, prototrophy and serologic characteristics of the parent. In relevant intestinal experimental models, it is avirulent and induces protection against challenge with virulent cholera vibrios. The mutant appears to be suitable for further evaluation in volunteers as a candidate living enteric vaccine against cholera and related enterotoxic enteropathies.