Engineering a wild-type yeast to be used for oral vaccine delivery

Saccharomyces boulardii is a probiotic yeast species, closely related to Saccharomyces cerevisiae, which is used in the treatment of patients suffering from acute diarrhea, cholera and various other intestinal diseases. The wild-type diploid S. boulardii exhibits certain morphological and physiological characteristics which help it colonize the human gut for a short period of time. These properties of S. boulardii suggest the idea of using this yeast as a means of delivering oral vaccines into the human gut. Accordingly, I first had to develop a transformation method and a stable selection strategy. This report describes our experiments which led us to use electroporation for transformation and the use of kanamycin resistance as a selectable marker. Using these techniques together, we were able to introduce plasmids into the yeast. Our future experiments will be directed towards expressing some of the vaccines candidates and testing them.