A study of antigenic variation in Vibrio cholerae.

The variations in Vibrio cholerae studied included changes from Ogawa to Inaba type, smooth+rough, and motile-+non-motile. With a sloppy-agar technique i t was possible to estimate the rate of formation of thcse variants (i.e. probable mutation rate 1 in 1 0 5 and 1 in lo4, respectively). It was possible to show that the action of antiserum in promoting the change from Ogawa to Inaba was selective rather than mutagenic. With the other two variations studied no selective process had to be considered owing to their high spontaneous rate of appearance. It may be said that all three variations studied were due to spontaneous mutants in the parent cultures giving rise to these forms.